Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/drivers/counter/104-quad-8.c b/drivers/counter/104-quad-8.c
new file mode 100644
index 0000000..00b113f
--- /dev/null
+++ b/drivers/counter/104-quad-8.c
@@ -0,0 +1,1367 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Counter driver for the ACCES 104-QUAD-8
+ * Copyright (C) 2016 William Breathitt Gray
+ *
+ * This driver supports the ACCES 104-QUAD-8 and ACCES 104-QUAD-4.
+ */
+#include <linux/bitops.h>
+#include <linux/counter.h>
+#include <linux/device.h>
+#include <linux/errno.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/types.h>
+#include <linux/io.h>
+#include <linux/ioport.h>
+#include <linux/isa.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/types.h>
+
+#define QUAD8_EXTENT 32
+
+static unsigned int base[max_num_isa_dev(QUAD8_EXTENT)];
+static unsigned int num_quad8;
+module_param_array(base, uint, &num_quad8, 0);
+MODULE_PARM_DESC(base, "ACCES 104-QUAD-8 base addresses");
+
+#define QUAD8_NUM_COUNTERS 8
+
+/**
+ * struct quad8_iio - IIO device private data structure
+ * @counter:		instance of the counter_device
+ * @preset:		array of preset values
+ * @count_mode:		array of count mode configurations
+ * @quadrature_mode:	array of quadrature mode configurations
+ * @quadrature_scale:	array of quadrature mode scale configurations
+ * @ab_enable:		array of A and B inputs enable configurations
+ * @preset_enable:	array of set_to_preset_on_index attribute configurations
+ * @synchronous_mode:	array of index function synchronous mode configurations
+ * @index_polarity:	array of index function polarity configurations
+ * @base:		base port address of the IIO device
+ */
+struct quad8_iio {
+	struct counter_device counter;
+	unsigned int preset[QUAD8_NUM_COUNTERS];
+	unsigned int count_mode[QUAD8_NUM_COUNTERS];
+	unsigned int quadrature_mode[QUAD8_NUM_COUNTERS];
+	unsigned int quadrature_scale[QUAD8_NUM_COUNTERS];
+	unsigned int ab_enable[QUAD8_NUM_COUNTERS];
+	unsigned int preset_enable[QUAD8_NUM_COUNTERS];
+	unsigned int synchronous_mode[QUAD8_NUM_COUNTERS];
+	unsigned int index_polarity[QUAD8_NUM_COUNTERS];
+	unsigned int base;
+};
+
+#define QUAD8_REG_CHAN_OP 0x11
+#define QUAD8_REG_INDEX_INPUT_LEVELS 0x16
+/* Borrow Toggle flip-flop */
+#define QUAD8_FLAG_BT BIT(0)
+/* Carry Toggle flip-flop */
+#define QUAD8_FLAG_CT BIT(1)
+/* Error flag */
+#define QUAD8_FLAG_E BIT(4)
+/* Up/Down flag */
+#define QUAD8_FLAG_UD BIT(5)
+/* Reset and Load Signal Decoders */
+#define QUAD8_CTR_RLD 0x00
+/* Counter Mode Register */
+#define QUAD8_CTR_CMR 0x20
+/* Input / Output Control Register */
+#define QUAD8_CTR_IOR 0x40
+/* Index Control Register */
+#define QUAD8_CTR_IDR 0x60
+/* Reset Byte Pointer (three byte data pointer) */
+#define QUAD8_RLD_RESET_BP 0x01
+/* Reset Counter */
+#define QUAD8_RLD_RESET_CNTR 0x02
+/* Reset Borrow Toggle, Carry Toggle, Compare Toggle, and Sign flags */
+#define QUAD8_RLD_RESET_FLAGS 0x04
+/* Reset Error flag */
+#define QUAD8_RLD_RESET_E 0x06
+/* Preset Register to Counter */
+#define QUAD8_RLD_PRESET_CNTR 0x08
+/* Transfer Counter to Output Latch */
+#define QUAD8_RLD_CNTR_OUT 0x10
+#define QUAD8_CHAN_OP_ENABLE_COUNTERS 0x00
+#define QUAD8_CHAN_OP_RESET_COUNTERS 0x01
+#define QUAD8_CMR_QUADRATURE_X1 0x08
+#define QUAD8_CMR_QUADRATURE_X2 0x10
+#define QUAD8_CMR_QUADRATURE_X4 0x18
+
+
+static int quad8_read_raw(struct iio_dev *indio_dev,
+	struct iio_chan_spec const *chan, int *val, int *val2, long mask)
+{
+	struct quad8_iio *const priv = iio_priv(indio_dev);
+	const int base_offset = priv->base + 2 * chan->channel;
+	unsigned int flags;
+	unsigned int borrow;
+	unsigned int carry;
+	int i;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		if (chan->type == IIO_INDEX) {
+			*val = !!(inb(priv->base + QUAD8_REG_INDEX_INPUT_LEVELS)
+				& BIT(chan->channel));
+			return IIO_VAL_INT;
+		}
+
+		flags = inb(base_offset + 1);
+		borrow = flags & QUAD8_FLAG_BT;
+		carry = !!(flags & QUAD8_FLAG_CT);
+
+		/* Borrow XOR Carry effectively doubles count range */
+		*val = (borrow ^ carry) << 24;
+
+		/* Reset Byte Pointer; transfer Counter to Output Latch */
+		outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP | QUAD8_RLD_CNTR_OUT,
+		     base_offset + 1);
+
+		for (i = 0; i < 3; i++)
+			*val |= (unsigned int)inb(base_offset) << (8 * i);
+
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_ENABLE:
+		*val = priv->ab_enable[chan->channel];
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_SCALE:
+		*val = 1;
+		*val2 = priv->quadrature_scale[chan->channel];
+		return IIO_VAL_FRACTIONAL_LOG2;
+	}
+
+	return -EINVAL;
+}
+
+static int quad8_write_raw(struct iio_dev *indio_dev,
+	struct iio_chan_spec const *chan, int val, int val2, long mask)
+{
+	struct quad8_iio *const priv = iio_priv(indio_dev);
+	const int base_offset = priv->base + 2 * chan->channel;
+	int i;
+	unsigned int ior_cfg;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		if (chan->type == IIO_INDEX)
+			return -EINVAL;
+
+		/* Only 24-bit values are supported */
+		if ((unsigned int)val > 0xFFFFFF)
+			return -EINVAL;
+
+		/* Reset Byte Pointer */
+		outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, base_offset + 1);
+
+		/* Counter can only be set via Preset Register */
+		for (i = 0; i < 3; i++)
+			outb(val >> (8 * i), base_offset);
+
+		/* Transfer Preset Register to Counter */
+		outb(QUAD8_CTR_RLD | QUAD8_RLD_PRESET_CNTR, base_offset + 1);
+
+		/* Reset Byte Pointer */
+		outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, base_offset + 1);
+
+		/* Set Preset Register back to original value */
+		val = priv->preset[chan->channel];
+		for (i = 0; i < 3; i++)
+			outb(val >> (8 * i), base_offset);
+
+		/* Reset Borrow, Carry, Compare, and Sign flags */
+		outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_FLAGS, base_offset + 1);
+		/* Reset Error flag */
+		outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_E, base_offset + 1);
+
+		return 0;
+	case IIO_CHAN_INFO_ENABLE:
+		/* only boolean values accepted */
+		if (val < 0 || val > 1)
+			return -EINVAL;
+
+		priv->ab_enable[chan->channel] = val;
+
+		ior_cfg = val | priv->preset_enable[chan->channel] << 1;
+
+		/* Load I/O control configuration */
+		outb(QUAD8_CTR_IOR | ior_cfg, base_offset + 1);
+
+		return 0;
+	case IIO_CHAN_INFO_SCALE:
+		/* Quadrature scaling only available in quadrature mode */
+		if (!priv->quadrature_mode[chan->channel] && (val2 || val != 1))
+			return -EINVAL;
+
+		/* Only three gain states (1, 0.5, 0.25) */
+		if (val == 1 && !val2)
+			priv->quadrature_scale[chan->channel] = 0;
+		else if (!val)
+			switch (val2) {
+			case 500000:
+				priv->quadrature_scale[chan->channel] = 1;
+				break;
+			case 250000:
+				priv->quadrature_scale[chan->channel] = 2;
+				break;
+			default:
+				return -EINVAL;
+			}
+		else
+			return -EINVAL;
+
+		return 0;
+	}
+
+	return -EINVAL;
+}
+
+static const struct iio_info quad8_info = {
+	.read_raw = quad8_read_raw,
+	.write_raw = quad8_write_raw
+};
+
+static ssize_t quad8_read_preset(struct iio_dev *indio_dev, uintptr_t private,
+	const struct iio_chan_spec *chan, char *buf)
+{
+	const struct quad8_iio *const priv = iio_priv(indio_dev);
+
+	return snprintf(buf, PAGE_SIZE, "%u\n", priv->preset[chan->channel]);
+}
+
+static ssize_t quad8_write_preset(struct iio_dev *indio_dev, uintptr_t private,
+	const struct iio_chan_spec *chan, const char *buf, size_t len)
+{
+	struct quad8_iio *const priv = iio_priv(indio_dev);
+	const int base_offset = priv->base + 2 * chan->channel;
+	unsigned int preset;
+	int ret;
+	int i;
+
+	ret = kstrtouint(buf, 0, &preset);
+	if (ret)
+		return ret;
+
+	/* Only 24-bit values are supported */
+	if (preset > 0xFFFFFF)
+		return -EINVAL;
+
+	priv->preset[chan->channel] = preset;
+
+	/* Reset Byte Pointer */
+	outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, base_offset + 1);
+
+	/* Set Preset Register */
+	for (i = 0; i < 3; i++)
+		outb(preset >> (8 * i), base_offset);
+
+	return len;
+}
+
+static ssize_t quad8_read_set_to_preset_on_index(struct iio_dev *indio_dev,
+	uintptr_t private, const struct iio_chan_spec *chan, char *buf)
+{
+	const struct quad8_iio *const priv = iio_priv(indio_dev);
+
+	return snprintf(buf, PAGE_SIZE, "%u\n",
+		!priv->preset_enable[chan->channel]);
+}
+
+static ssize_t quad8_write_set_to_preset_on_index(struct iio_dev *indio_dev,
+	uintptr_t private, const struct iio_chan_spec *chan, const char *buf,
+	size_t len)
+{
+	struct quad8_iio *const priv = iio_priv(indio_dev);
+	const int base_offset = priv->base + 2 * chan->channel + 1;
+	bool preset_enable;
+	int ret;
+	unsigned int ior_cfg;
+
+	ret = kstrtobool(buf, &preset_enable);
+	if (ret)
+		return ret;
+
+	/* Preset enable is active low in Input/Output Control register */
+	preset_enable = !preset_enable;
+
+	priv->preset_enable[chan->channel] = preset_enable;
+
+	ior_cfg = priv->ab_enable[chan->channel] |
+		(unsigned int)preset_enable << 1;
+
+	/* Load I/O control configuration to Input / Output Control Register */
+	outb(QUAD8_CTR_IOR | ior_cfg, base_offset);
+
+	return len;
+}
+
+static const char *const quad8_noise_error_states[] = {
+	"No excessive noise is present at the count inputs",
+	"Excessive noise is present at the count inputs"
+};
+
+static int quad8_get_noise_error(struct iio_dev *indio_dev,
+	const struct iio_chan_spec *chan)
+{
+	struct quad8_iio *const priv = iio_priv(indio_dev);
+	const int base_offset = priv->base + 2 * chan->channel + 1;
+
+	return !!(inb(base_offset) & QUAD8_FLAG_E);
+}
+
+static const struct iio_enum quad8_noise_error_enum = {
+	.items = quad8_noise_error_states,
+	.num_items = ARRAY_SIZE(quad8_noise_error_states),
+	.get = quad8_get_noise_error
+};
+
+static const char *const quad8_count_direction_states[] = {
+	"down",
+	"up"
+};
+
+static int quad8_get_count_direction(struct iio_dev *indio_dev,
+	const struct iio_chan_spec *chan)
+{
+	struct quad8_iio *const priv = iio_priv(indio_dev);
+	const int base_offset = priv->base + 2 * chan->channel + 1;
+
+	return !!(inb(base_offset) & QUAD8_FLAG_UD);
+}
+
+static const struct iio_enum quad8_count_direction_enum = {
+	.items = quad8_count_direction_states,
+	.num_items = ARRAY_SIZE(quad8_count_direction_states),
+	.get = quad8_get_count_direction
+};
+
+static const char *const quad8_count_modes[] = {
+	"normal",
+	"range limit",
+	"non-recycle",
+	"modulo-n"
+};
+
+static int quad8_set_count_mode(struct iio_dev *indio_dev,
+	const struct iio_chan_spec *chan, unsigned int cnt_mode)
+{
+	struct quad8_iio *const priv = iio_priv(indio_dev);
+	unsigned int mode_cfg = cnt_mode << 1;
+	const int base_offset = priv->base + 2 * chan->channel + 1;
+
+	priv->count_mode[chan->channel] = cnt_mode;
+
+	/* Add quadrature mode configuration */
+	if (priv->quadrature_mode[chan->channel])
+		mode_cfg |= (priv->quadrature_scale[chan->channel] + 1) << 3;
+
+	/* Load mode configuration to Counter Mode Register */
+	outb(QUAD8_CTR_CMR | mode_cfg, base_offset);
+
+	return 0;
+}
+
+static int quad8_get_count_mode(struct iio_dev *indio_dev,
+	const struct iio_chan_spec *chan)
+{
+	const struct quad8_iio *const priv = iio_priv(indio_dev);
+
+	return priv->count_mode[chan->channel];
+}
+
+static const struct iio_enum quad8_count_mode_enum = {
+	.items = quad8_count_modes,
+	.num_items = ARRAY_SIZE(quad8_count_modes),
+	.set = quad8_set_count_mode,
+	.get = quad8_get_count_mode
+};
+
+static const char *const quad8_synchronous_modes[] = {
+	"non-synchronous",
+	"synchronous"
+};
+
+static int quad8_set_synchronous_mode(struct iio_dev *indio_dev,
+	const struct iio_chan_spec *chan, unsigned int synchronous_mode)
+{
+	struct quad8_iio *const priv = iio_priv(indio_dev);
+	const unsigned int idr_cfg = synchronous_mode |
+		priv->index_polarity[chan->channel] << 1;
+	const int base_offset = priv->base + 2 * chan->channel + 1;
+
+	/* Index function must be non-synchronous in non-quadrature mode */
+	if (synchronous_mode && !priv->quadrature_mode[chan->channel])
+		return -EINVAL;
+
+	priv->synchronous_mode[chan->channel] = synchronous_mode;
+
+	/* Load Index Control configuration to Index Control Register */
+	outb(QUAD8_CTR_IDR | idr_cfg, base_offset);
+
+	return 0;
+}
+
+static int quad8_get_synchronous_mode(struct iio_dev *indio_dev,
+	const struct iio_chan_spec *chan)
+{
+	const struct quad8_iio *const priv = iio_priv(indio_dev);
+
+	return priv->synchronous_mode[chan->channel];
+}
+
+static const struct iio_enum quad8_synchronous_mode_enum = {
+	.items = quad8_synchronous_modes,
+	.num_items = ARRAY_SIZE(quad8_synchronous_modes),
+	.set = quad8_set_synchronous_mode,
+	.get = quad8_get_synchronous_mode
+};
+
+static const char *const quad8_quadrature_modes[] = {
+	"non-quadrature",
+	"quadrature"
+};
+
+static int quad8_set_quadrature_mode(struct iio_dev *indio_dev,
+	const struct iio_chan_spec *chan, unsigned int quadrature_mode)
+{
+	struct quad8_iio *const priv = iio_priv(indio_dev);
+	unsigned int mode_cfg = priv->count_mode[chan->channel] << 1;
+	const int base_offset = priv->base + 2 * chan->channel + 1;
+
+	if (quadrature_mode)
+		mode_cfg |= (priv->quadrature_scale[chan->channel] + 1) << 3;
+	else {
+		/* Quadrature scaling only available in quadrature mode */
+		priv->quadrature_scale[chan->channel] = 0;
+
+		/* Synchronous function not supported in non-quadrature mode */
+		if (priv->synchronous_mode[chan->channel])
+			quad8_set_synchronous_mode(indio_dev, chan, 0);
+	}
+
+	priv->quadrature_mode[chan->channel] = quadrature_mode;
+
+	/* Load mode configuration to Counter Mode Register */
+	outb(QUAD8_CTR_CMR | mode_cfg, base_offset);
+
+	return 0;
+}
+
+static int quad8_get_quadrature_mode(struct iio_dev *indio_dev,
+	const struct iio_chan_spec *chan)
+{
+	const struct quad8_iio *const priv = iio_priv(indio_dev);
+
+	return priv->quadrature_mode[chan->channel];
+}
+
+static const struct iio_enum quad8_quadrature_mode_enum = {
+	.items = quad8_quadrature_modes,
+	.num_items = ARRAY_SIZE(quad8_quadrature_modes),
+	.set = quad8_set_quadrature_mode,
+	.get = quad8_get_quadrature_mode
+};
+
+static const char *const quad8_index_polarity_modes[] = {
+	"negative",
+	"positive"
+};
+
+static int quad8_set_index_polarity(struct iio_dev *indio_dev,
+	const struct iio_chan_spec *chan, unsigned int index_polarity)
+{
+	struct quad8_iio *const priv = iio_priv(indio_dev);
+	const unsigned int idr_cfg = priv->synchronous_mode[chan->channel] |
+		index_polarity << 1;
+	const int base_offset = priv->base + 2 * chan->channel + 1;
+
+	priv->index_polarity[chan->channel] = index_polarity;
+
+	/* Load Index Control configuration to Index Control Register */
+	outb(QUAD8_CTR_IDR | idr_cfg, base_offset);
+
+	return 0;
+}
+
+static int quad8_get_index_polarity(struct iio_dev *indio_dev,
+	const struct iio_chan_spec *chan)
+{
+	const struct quad8_iio *const priv = iio_priv(indio_dev);
+
+	return priv->index_polarity[chan->channel];
+}
+
+static const struct iio_enum quad8_index_polarity_enum = {
+	.items = quad8_index_polarity_modes,
+	.num_items = ARRAY_SIZE(quad8_index_polarity_modes),
+	.set = quad8_set_index_polarity,
+	.get = quad8_get_index_polarity
+};
+
+static const struct iio_chan_spec_ext_info quad8_count_ext_info[] = {
+	{
+		.name = "preset",
+		.shared = IIO_SEPARATE,
+		.read = quad8_read_preset,
+		.write = quad8_write_preset
+	},
+	{
+		.name = "set_to_preset_on_index",
+		.shared = IIO_SEPARATE,
+		.read = quad8_read_set_to_preset_on_index,
+		.write = quad8_write_set_to_preset_on_index
+	},
+	IIO_ENUM("noise_error", IIO_SEPARATE, &quad8_noise_error_enum),
+	IIO_ENUM_AVAILABLE("noise_error", &quad8_noise_error_enum),
+	IIO_ENUM("count_direction", IIO_SEPARATE, &quad8_count_direction_enum),
+	IIO_ENUM_AVAILABLE("count_direction", &quad8_count_direction_enum),
+	IIO_ENUM("count_mode", IIO_SEPARATE, &quad8_count_mode_enum),
+	IIO_ENUM_AVAILABLE("count_mode", &quad8_count_mode_enum),
+	IIO_ENUM("quadrature_mode", IIO_SEPARATE, &quad8_quadrature_mode_enum),
+	IIO_ENUM_AVAILABLE("quadrature_mode", &quad8_quadrature_mode_enum),
+	{}
+};
+
+static const struct iio_chan_spec_ext_info quad8_index_ext_info[] = {
+	IIO_ENUM("synchronous_mode", IIO_SEPARATE,
+		&quad8_synchronous_mode_enum),
+	IIO_ENUM_AVAILABLE("synchronous_mode", &quad8_synchronous_mode_enum),
+	IIO_ENUM("index_polarity", IIO_SEPARATE, &quad8_index_polarity_enum),
+	IIO_ENUM_AVAILABLE("index_polarity", &quad8_index_polarity_enum),
+	{}
+};
+
+#define QUAD8_COUNT_CHAN(_chan) {					\
+	.type = IIO_COUNT,						\
+	.channel = (_chan),						\
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |			\
+		BIT(IIO_CHAN_INFO_ENABLE) | BIT(IIO_CHAN_INFO_SCALE),	\
+	.ext_info = quad8_count_ext_info,				\
+	.indexed = 1							\
+}
+
+#define QUAD8_INDEX_CHAN(_chan) {			\
+	.type = IIO_INDEX,				\
+	.channel = (_chan),				\
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),	\
+	.ext_info = quad8_index_ext_info,		\
+	.indexed = 1					\
+}
+
+static const struct iio_chan_spec quad8_channels[] = {
+	QUAD8_COUNT_CHAN(0), QUAD8_INDEX_CHAN(0),
+	QUAD8_COUNT_CHAN(1), QUAD8_INDEX_CHAN(1),
+	QUAD8_COUNT_CHAN(2), QUAD8_INDEX_CHAN(2),
+	QUAD8_COUNT_CHAN(3), QUAD8_INDEX_CHAN(3),
+	QUAD8_COUNT_CHAN(4), QUAD8_INDEX_CHAN(4),
+	QUAD8_COUNT_CHAN(5), QUAD8_INDEX_CHAN(5),
+	QUAD8_COUNT_CHAN(6), QUAD8_INDEX_CHAN(6),
+	QUAD8_COUNT_CHAN(7), QUAD8_INDEX_CHAN(7)
+};
+
+static int quad8_signal_read(struct counter_device *counter,
+	struct counter_signal *signal, struct counter_signal_read_value *val)
+{
+	const struct quad8_iio *const priv = counter->priv;
+	unsigned int state;
+	enum counter_signal_level level;
+
+	/* Only Index signal levels can be read */
+	if (signal->id < 16)
+		return -EINVAL;
+
+	state = inb(priv->base + QUAD8_REG_INDEX_INPUT_LEVELS)
+		& BIT(signal->id - 16);
+
+	level = (state) ? COUNTER_SIGNAL_LEVEL_HIGH : COUNTER_SIGNAL_LEVEL_LOW;
+
+	counter_signal_read_value_set(val, COUNTER_SIGNAL_LEVEL, &level);
+
+	return 0;
+}
+
+static int quad8_count_read(struct counter_device *counter,
+	struct counter_count *count, struct counter_count_read_value *val)
+{
+	const struct quad8_iio *const priv = counter->priv;
+	const int base_offset = priv->base + 2 * count->id;
+	unsigned int flags;
+	unsigned int borrow;
+	unsigned int carry;
+	unsigned long position;
+	int i;
+
+	flags = inb(base_offset + 1);
+	borrow = flags & QUAD8_FLAG_BT;
+	carry = !!(flags & QUAD8_FLAG_CT);
+
+	/* Borrow XOR Carry effectively doubles count range */
+	position = (unsigned long)(borrow ^ carry) << 24;
+
+	/* Reset Byte Pointer; transfer Counter to Output Latch */
+	outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP | QUAD8_RLD_CNTR_OUT,
+	     base_offset + 1);
+
+	for (i = 0; i < 3; i++)
+		position |= (unsigned long)inb(base_offset) << (8 * i);
+
+	counter_count_read_value_set(val, COUNTER_COUNT_POSITION, &position);
+
+	return 0;
+}
+
+static int quad8_count_write(struct counter_device *counter,
+	struct counter_count *count, struct counter_count_write_value *val)
+{
+	const struct quad8_iio *const priv = counter->priv;
+	const int base_offset = priv->base + 2 * count->id;
+	int err;
+	unsigned long position;
+	int i;
+
+	err = counter_count_write_value_get(&position, COUNTER_COUNT_POSITION,
+					    val);
+	if (err)
+		return err;
+
+	/* Only 24-bit values are supported */
+	if (position > 0xFFFFFF)
+		return -EINVAL;
+
+	/* Reset Byte Pointer */
+	outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, base_offset + 1);
+
+	/* Counter can only be set via Preset Register */
+	for (i = 0; i < 3; i++)
+		outb(position >> (8 * i), base_offset);
+
+	/* Transfer Preset Register to Counter */
+	outb(QUAD8_CTR_RLD | QUAD8_RLD_PRESET_CNTR, base_offset + 1);
+
+	/* Reset Byte Pointer */
+	outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, base_offset + 1);
+
+	/* Set Preset Register back to original value */
+	position = priv->preset[count->id];
+	for (i = 0; i < 3; i++)
+		outb(position >> (8 * i), base_offset);
+
+	/* Reset Borrow, Carry, Compare, and Sign flags */
+	outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_FLAGS, base_offset + 1);
+	/* Reset Error flag */
+	outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_E, base_offset + 1);
+
+	return 0;
+}
+
+enum quad8_count_function {
+	QUAD8_COUNT_FUNCTION_PULSE_DIRECTION = 0,
+	QUAD8_COUNT_FUNCTION_QUADRATURE_X1,
+	QUAD8_COUNT_FUNCTION_QUADRATURE_X2,
+	QUAD8_COUNT_FUNCTION_QUADRATURE_X4
+};
+
+static enum counter_count_function quad8_count_functions_list[] = {
+	[QUAD8_COUNT_FUNCTION_PULSE_DIRECTION] = COUNTER_COUNT_FUNCTION_PULSE_DIRECTION,
+	[QUAD8_COUNT_FUNCTION_QUADRATURE_X1] = COUNTER_COUNT_FUNCTION_QUADRATURE_X1_A,
+	[QUAD8_COUNT_FUNCTION_QUADRATURE_X2] = COUNTER_COUNT_FUNCTION_QUADRATURE_X2_A,
+	[QUAD8_COUNT_FUNCTION_QUADRATURE_X4] = COUNTER_COUNT_FUNCTION_QUADRATURE_X4
+};
+
+static int quad8_function_get(struct counter_device *counter,
+	struct counter_count *count, size_t *function)
+{
+	const struct quad8_iio *const priv = counter->priv;
+	const int id = count->id;
+	const unsigned int quadrature_mode = priv->quadrature_mode[id];
+	const unsigned int scale = priv->quadrature_scale[id];
+
+	if (quadrature_mode)
+		switch (scale) {
+		case 0:
+			*function = QUAD8_COUNT_FUNCTION_QUADRATURE_X1;
+			break;
+		case 1:
+			*function = QUAD8_COUNT_FUNCTION_QUADRATURE_X2;
+			break;
+		case 2:
+			*function = QUAD8_COUNT_FUNCTION_QUADRATURE_X4;
+			break;
+		}
+	else
+		*function = QUAD8_COUNT_FUNCTION_PULSE_DIRECTION;
+
+	return 0;
+}
+
+static int quad8_function_set(struct counter_device *counter,
+	struct counter_count *count, size_t function)
+{
+	struct quad8_iio *const priv = counter->priv;
+	const int id = count->id;
+	unsigned int *const quadrature_mode = priv->quadrature_mode + id;
+	unsigned int *const scale = priv->quadrature_scale + id;
+	unsigned int mode_cfg = priv->count_mode[id] << 1;
+	unsigned int *const synchronous_mode = priv->synchronous_mode + id;
+	const unsigned int idr_cfg = priv->index_polarity[id] << 1;
+	const int base_offset = priv->base + 2 * id + 1;
+
+	if (function == QUAD8_COUNT_FUNCTION_PULSE_DIRECTION) {
+		*quadrature_mode = 0;
+
+		/* Quadrature scaling only available in quadrature mode */
+		*scale = 0;
+
+		/* Synchronous function not supported in non-quadrature mode */
+		if (*synchronous_mode) {
+			*synchronous_mode = 0;
+			/* Disable synchronous function mode */
+			outb(QUAD8_CTR_IDR | idr_cfg, base_offset);
+		}
+	} else {
+		*quadrature_mode = 1;
+
+		switch (function) {
+		case QUAD8_COUNT_FUNCTION_QUADRATURE_X1:
+			*scale = 0;
+			mode_cfg |= QUAD8_CMR_QUADRATURE_X1;
+			break;
+		case QUAD8_COUNT_FUNCTION_QUADRATURE_X2:
+			*scale = 1;
+			mode_cfg |= QUAD8_CMR_QUADRATURE_X2;
+			break;
+		case QUAD8_COUNT_FUNCTION_QUADRATURE_X4:
+			*scale = 2;
+			mode_cfg |= QUAD8_CMR_QUADRATURE_X4;
+			break;
+		}
+	}
+
+	/* Load mode configuration to Counter Mode Register */
+	outb(QUAD8_CTR_CMR | mode_cfg, base_offset);
+
+	return 0;
+}
+
+static void quad8_direction_get(struct counter_device *counter,
+	struct counter_count *count, enum counter_count_direction *direction)
+{
+	const struct quad8_iio *const priv = counter->priv;
+	unsigned int ud_flag;
+	const unsigned int flag_addr = priv->base + 2 * count->id + 1;
+
+	/* U/D flag: nonzero = up, zero = down */
+	ud_flag = inb(flag_addr) & QUAD8_FLAG_UD;
+
+	*direction = (ud_flag) ? COUNTER_COUNT_DIRECTION_FORWARD :
+		COUNTER_COUNT_DIRECTION_BACKWARD;
+}
+
+enum quad8_synapse_action {
+	QUAD8_SYNAPSE_ACTION_NONE = 0,
+	QUAD8_SYNAPSE_ACTION_RISING_EDGE,
+	QUAD8_SYNAPSE_ACTION_FALLING_EDGE,
+	QUAD8_SYNAPSE_ACTION_BOTH_EDGES
+};
+
+static enum counter_synapse_action quad8_index_actions_list[] = {
+	[QUAD8_SYNAPSE_ACTION_NONE] = COUNTER_SYNAPSE_ACTION_NONE,
+	[QUAD8_SYNAPSE_ACTION_RISING_EDGE] = COUNTER_SYNAPSE_ACTION_RISING_EDGE
+};
+
+static enum counter_synapse_action quad8_synapse_actions_list[] = {
+	[QUAD8_SYNAPSE_ACTION_NONE] = COUNTER_SYNAPSE_ACTION_NONE,
+	[QUAD8_SYNAPSE_ACTION_RISING_EDGE] = COUNTER_SYNAPSE_ACTION_RISING_EDGE,
+	[QUAD8_SYNAPSE_ACTION_FALLING_EDGE] = COUNTER_SYNAPSE_ACTION_FALLING_EDGE,
+	[QUAD8_SYNAPSE_ACTION_BOTH_EDGES] = COUNTER_SYNAPSE_ACTION_BOTH_EDGES
+};
+
+static int quad8_action_get(struct counter_device *counter,
+	struct counter_count *count, struct counter_synapse *synapse,
+	size_t *action)
+{
+	struct quad8_iio *const priv = counter->priv;
+	int err;
+	size_t function = 0;
+	const size_t signal_a_id = count->synapses[0].signal->id;
+	enum counter_count_direction direction;
+
+	/* Handle Index signals */
+	if (synapse->signal->id >= 16) {
+		if (priv->preset_enable[count->id])
+			*action = QUAD8_SYNAPSE_ACTION_RISING_EDGE;
+		else
+			*action = QUAD8_SYNAPSE_ACTION_NONE;
+
+		return 0;
+	}
+
+	err = quad8_function_get(counter, count, &function);
+	if (err)
+		return err;
+
+	/* Default action mode */
+	*action = QUAD8_SYNAPSE_ACTION_NONE;
+
+	/* Determine action mode based on current count function mode */
+	switch (function) {
+	case QUAD8_COUNT_FUNCTION_PULSE_DIRECTION:
+		if (synapse->signal->id == signal_a_id)
+			*action = QUAD8_SYNAPSE_ACTION_RISING_EDGE;
+		break;
+	case QUAD8_COUNT_FUNCTION_QUADRATURE_X1:
+		if (synapse->signal->id == signal_a_id) {
+			quad8_direction_get(counter, count, &direction);
+
+			if (direction == COUNTER_COUNT_DIRECTION_FORWARD)
+				*action = QUAD8_SYNAPSE_ACTION_RISING_EDGE;
+			else
+				*action = QUAD8_SYNAPSE_ACTION_FALLING_EDGE;
+		}
+		break;
+	case QUAD8_COUNT_FUNCTION_QUADRATURE_X2:
+		if (synapse->signal->id == signal_a_id)
+			*action = QUAD8_SYNAPSE_ACTION_BOTH_EDGES;
+		break;
+	case QUAD8_COUNT_FUNCTION_QUADRATURE_X4:
+		*action = QUAD8_SYNAPSE_ACTION_BOTH_EDGES;
+		break;
+	}
+
+	return 0;
+}
+
+static const struct counter_ops quad8_ops = {
+	.signal_read = quad8_signal_read,
+	.count_read = quad8_count_read,
+	.count_write = quad8_count_write,
+	.function_get = quad8_function_get,
+	.function_set = quad8_function_set,
+	.action_get = quad8_action_get
+};
+
+static int quad8_index_polarity_get(struct counter_device *counter,
+	struct counter_signal *signal, size_t *index_polarity)
+{
+	const struct quad8_iio *const priv = counter->priv;
+	const size_t channel_id = signal->id - 16;
+
+	*index_polarity = priv->index_polarity[channel_id];
+
+	return 0;
+}
+
+static int quad8_index_polarity_set(struct counter_device *counter,
+	struct counter_signal *signal, size_t index_polarity)
+{
+	struct quad8_iio *const priv = counter->priv;
+	const size_t channel_id = signal->id - 16;
+	const unsigned int idr_cfg = priv->synchronous_mode[channel_id] |
+		index_polarity << 1;
+	const int base_offset = priv->base + 2 * channel_id + 1;
+
+	priv->index_polarity[channel_id] = index_polarity;
+
+	/* Load Index Control configuration to Index Control Register */
+	outb(QUAD8_CTR_IDR | idr_cfg, base_offset);
+
+	return 0;
+}
+
+static struct counter_signal_enum_ext quad8_index_pol_enum = {
+	.items = quad8_index_polarity_modes,
+	.num_items = ARRAY_SIZE(quad8_index_polarity_modes),
+	.get = quad8_index_polarity_get,
+	.set = quad8_index_polarity_set
+};
+
+static int quad8_synchronous_mode_get(struct counter_device *counter,
+	struct counter_signal *signal, size_t *synchronous_mode)
+{
+	const struct quad8_iio *const priv = counter->priv;
+	const size_t channel_id = signal->id - 16;
+
+	*synchronous_mode = priv->synchronous_mode[channel_id];
+
+	return 0;
+}
+
+static int quad8_synchronous_mode_set(struct counter_device *counter,
+	struct counter_signal *signal, size_t synchronous_mode)
+{
+	struct quad8_iio *const priv = counter->priv;
+	const size_t channel_id = signal->id - 16;
+	const unsigned int idr_cfg = synchronous_mode |
+		priv->index_polarity[channel_id] << 1;
+	const int base_offset = priv->base + 2 * channel_id + 1;
+
+	/* Index function must be non-synchronous in non-quadrature mode */
+	if (synchronous_mode && !priv->quadrature_mode[channel_id])
+		return -EINVAL;
+
+	priv->synchronous_mode[channel_id] = synchronous_mode;
+
+	/* Load Index Control configuration to Index Control Register */
+	outb(QUAD8_CTR_IDR | idr_cfg, base_offset);
+
+	return 0;
+}
+
+static struct counter_signal_enum_ext quad8_syn_mode_enum = {
+	.items = quad8_synchronous_modes,
+	.num_items = ARRAY_SIZE(quad8_synchronous_modes),
+	.get = quad8_synchronous_mode_get,
+	.set = quad8_synchronous_mode_set
+};
+
+static ssize_t quad8_count_floor_read(struct counter_device *counter,
+	struct counter_count *count, void *private, char *buf)
+{
+	/* Only a floor of 0 is supported */
+	return sprintf(buf, "0\n");
+}
+
+static int quad8_count_mode_get(struct counter_device *counter,
+	struct counter_count *count, size_t *cnt_mode)
+{
+	const struct quad8_iio *const priv = counter->priv;
+
+	/* Map 104-QUAD-8 count mode to Generic Counter count mode */
+	switch (priv->count_mode[count->id]) {
+	case 0:
+		*cnt_mode = COUNTER_COUNT_MODE_NORMAL;
+		break;
+	case 1:
+		*cnt_mode = COUNTER_COUNT_MODE_RANGE_LIMIT;
+		break;
+	case 2:
+		*cnt_mode = COUNTER_COUNT_MODE_NON_RECYCLE;
+		break;
+	case 3:
+		*cnt_mode = COUNTER_COUNT_MODE_MODULO_N;
+		break;
+	}
+
+	return 0;
+}
+
+static int quad8_count_mode_set(struct counter_device *counter,
+	struct counter_count *count, size_t cnt_mode)
+{
+	struct quad8_iio *const priv = counter->priv;
+	unsigned int mode_cfg;
+	const int base_offset = priv->base + 2 * count->id + 1;
+
+	/* Map Generic Counter count mode to 104-QUAD-8 count mode */
+	switch (cnt_mode) {
+	case COUNTER_COUNT_MODE_NORMAL:
+		cnt_mode = 0;
+		break;
+	case COUNTER_COUNT_MODE_RANGE_LIMIT:
+		cnt_mode = 1;
+		break;
+	case COUNTER_COUNT_MODE_NON_RECYCLE:
+		cnt_mode = 2;
+		break;
+	case COUNTER_COUNT_MODE_MODULO_N:
+		cnt_mode = 3;
+		break;
+	}
+
+	priv->count_mode[count->id] = cnt_mode;
+
+	/* Set count mode configuration value */
+	mode_cfg = cnt_mode << 1;
+
+	/* Add quadrature mode configuration */
+	if (priv->quadrature_mode[count->id])
+		mode_cfg |= (priv->quadrature_scale[count->id] + 1) << 3;
+
+	/* Load mode configuration to Counter Mode Register */
+	outb(QUAD8_CTR_CMR | mode_cfg, base_offset);
+
+	return 0;
+}
+
+static struct counter_count_enum_ext quad8_cnt_mode_enum = {
+	.items = counter_count_mode_str,
+	.num_items = ARRAY_SIZE(counter_count_mode_str),
+	.get = quad8_count_mode_get,
+	.set = quad8_count_mode_set
+};
+
+static ssize_t quad8_count_direction_read(struct counter_device *counter,
+	struct counter_count *count, void *priv, char *buf)
+{
+	enum counter_count_direction dir;
+
+	quad8_direction_get(counter, count, &dir);
+
+	return sprintf(buf, "%s\n", counter_count_direction_str[dir]);
+}
+
+static ssize_t quad8_count_enable_read(struct counter_device *counter,
+	struct counter_count *count, void *private, char *buf)
+{
+	const struct quad8_iio *const priv = counter->priv;
+
+	return sprintf(buf, "%u\n", priv->ab_enable[count->id]);
+}
+
+static ssize_t quad8_count_enable_write(struct counter_device *counter,
+	struct counter_count *count, void *private, const char *buf, size_t len)
+{
+	struct quad8_iio *const priv = counter->priv;
+	const int base_offset = priv->base + 2 * count->id;
+	int err;
+	bool ab_enable;
+	unsigned int ior_cfg;
+
+	err = kstrtobool(buf, &ab_enable);
+	if (err)
+		return err;
+
+	priv->ab_enable[count->id] = ab_enable;
+
+	ior_cfg = ab_enable | priv->preset_enable[count->id] << 1;
+
+	/* Load I/O control configuration */
+	outb(QUAD8_CTR_IOR | ior_cfg, base_offset + 1);
+
+	return len;
+}
+
+static int quad8_error_noise_get(struct counter_device *counter,
+	struct counter_count *count, size_t *noise_error)
+{
+	const struct quad8_iio *const priv = counter->priv;
+	const int base_offset = priv->base + 2 * count->id + 1;
+
+	*noise_error = !!(inb(base_offset) & QUAD8_FLAG_E);
+
+	return 0;
+}
+
+static struct counter_count_enum_ext quad8_error_noise_enum = {
+	.items = quad8_noise_error_states,
+	.num_items = ARRAY_SIZE(quad8_noise_error_states),
+	.get = quad8_error_noise_get
+};
+
+static ssize_t quad8_count_preset_read(struct counter_device *counter,
+	struct counter_count *count, void *private, char *buf)
+{
+	const struct quad8_iio *const priv = counter->priv;
+
+	return sprintf(buf, "%u\n", priv->preset[count->id]);
+}
+
+static ssize_t quad8_count_preset_write(struct counter_device *counter,
+	struct counter_count *count, void *private, const char *buf, size_t len)
+{
+	struct quad8_iio *const priv = counter->priv;
+	const int base_offset = priv->base + 2 * count->id;
+	unsigned int preset;
+	int ret;
+	int i;
+
+	ret = kstrtouint(buf, 0, &preset);
+	if (ret)
+		return ret;
+
+	/* Only 24-bit values are supported */
+	if (preset > 0xFFFFFF)
+		return -EINVAL;
+
+	priv->preset[count->id] = preset;
+
+	/* Reset Byte Pointer */
+	outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, base_offset + 1);
+
+	/* Set Preset Register */
+	for (i = 0; i < 3; i++)
+		outb(preset >> (8 * i), base_offset);
+
+	return len;
+}
+
+static ssize_t quad8_count_ceiling_read(struct counter_device *counter,
+	struct counter_count *count, void *private, char *buf)
+{
+	const struct quad8_iio *const priv = counter->priv;
+
+	/* Range Limit and Modulo-N count modes use preset value as ceiling */
+	switch (priv->count_mode[count->id]) {
+	case 1:
+	case 3:
+		return quad8_count_preset_read(counter, count, private, buf);
+	}
+
+	/* By default 0x1FFFFFF (25 bits unsigned) is maximum count */
+	return sprintf(buf, "33554431\n");
+}
+
+static ssize_t quad8_count_ceiling_write(struct counter_device *counter,
+	struct counter_count *count, void *private, const char *buf, size_t len)
+{
+	struct quad8_iio *const priv = counter->priv;
+
+	/* Range Limit and Modulo-N count modes use preset value as ceiling */
+	switch (priv->count_mode[count->id]) {
+	case 1:
+	case 3:
+		return quad8_count_preset_write(counter, count, private, buf,
+						len);
+	}
+
+	return len;
+}
+
+static ssize_t quad8_count_preset_enable_read(struct counter_device *counter,
+	struct counter_count *count, void *private, char *buf)
+{
+	const struct quad8_iio *const priv = counter->priv;
+
+	return sprintf(buf, "%u\n", !priv->preset_enable[count->id]);
+}
+
+static ssize_t quad8_count_preset_enable_write(struct counter_device *counter,
+	struct counter_count *count, void *private, const char *buf, size_t len)
+{
+	struct quad8_iio *const priv = counter->priv;
+	const int base_offset = priv->base + 2 * count->id + 1;
+	bool preset_enable;
+	int ret;
+	unsigned int ior_cfg;
+
+	ret = kstrtobool(buf, &preset_enable);
+	if (ret)
+		return ret;
+
+	/* Preset enable is active low in Input/Output Control register */
+	preset_enable = !preset_enable;
+
+	priv->preset_enable[count->id] = preset_enable;
+
+	ior_cfg = priv->ab_enable[count->id] | (unsigned int)preset_enable << 1;
+
+	/* Load I/O control configuration to Input / Output Control Register */
+	outb(QUAD8_CTR_IOR | ior_cfg, base_offset);
+
+	return len;
+}
+
+static const struct counter_signal_ext quad8_index_ext[] = {
+	COUNTER_SIGNAL_ENUM("index_polarity", &quad8_index_pol_enum),
+	COUNTER_SIGNAL_ENUM_AVAILABLE("index_polarity",	&quad8_index_pol_enum),
+	COUNTER_SIGNAL_ENUM("synchronous_mode", &quad8_syn_mode_enum),
+	COUNTER_SIGNAL_ENUM_AVAILABLE("synchronous_mode", &quad8_syn_mode_enum)
+};
+
+#define	QUAD8_QUAD_SIGNAL(_id, _name) {	\
+	.id = (_id),			\
+	.name = (_name)			\
+}
+
+#define	QUAD8_INDEX_SIGNAL(_id, _name) {	\
+	.id = (_id),				\
+	.name = (_name),			\
+	.ext = quad8_index_ext,			\
+	.num_ext = ARRAY_SIZE(quad8_index_ext)	\
+}
+
+static struct counter_signal quad8_signals[] = {
+	QUAD8_QUAD_SIGNAL(0, "Channel 1 Quadrature A"),
+	QUAD8_QUAD_SIGNAL(1, "Channel 1 Quadrature B"),
+	QUAD8_QUAD_SIGNAL(2, "Channel 2 Quadrature A"),
+	QUAD8_QUAD_SIGNAL(3, "Channel 2 Quadrature B"),
+	QUAD8_QUAD_SIGNAL(4, "Channel 3 Quadrature A"),
+	QUAD8_QUAD_SIGNAL(5, "Channel 3 Quadrature B"),
+	QUAD8_QUAD_SIGNAL(6, "Channel 4 Quadrature A"),
+	QUAD8_QUAD_SIGNAL(7, "Channel 4 Quadrature B"),
+	QUAD8_QUAD_SIGNAL(8, "Channel 5 Quadrature A"),
+	QUAD8_QUAD_SIGNAL(9, "Channel 5 Quadrature B"),
+	QUAD8_QUAD_SIGNAL(10, "Channel 6 Quadrature A"),
+	QUAD8_QUAD_SIGNAL(11, "Channel 6 Quadrature B"),
+	QUAD8_QUAD_SIGNAL(12, "Channel 7 Quadrature A"),
+	QUAD8_QUAD_SIGNAL(13, "Channel 7 Quadrature B"),
+	QUAD8_QUAD_SIGNAL(14, "Channel 8 Quadrature A"),
+	QUAD8_QUAD_SIGNAL(15, "Channel 8 Quadrature B"),
+	QUAD8_INDEX_SIGNAL(16, "Channel 1 Index"),
+	QUAD8_INDEX_SIGNAL(17, "Channel 2 Index"),
+	QUAD8_INDEX_SIGNAL(18, "Channel 3 Index"),
+	QUAD8_INDEX_SIGNAL(19, "Channel 4 Index"),
+	QUAD8_INDEX_SIGNAL(20, "Channel 5 Index"),
+	QUAD8_INDEX_SIGNAL(21, "Channel 6 Index"),
+	QUAD8_INDEX_SIGNAL(22, "Channel 7 Index"),
+	QUAD8_INDEX_SIGNAL(23, "Channel 8 Index")
+};
+
+#define QUAD8_COUNT_SYNAPSES(_id) {					\
+	{								\
+		.actions_list = quad8_synapse_actions_list,		\
+		.num_actions = ARRAY_SIZE(quad8_synapse_actions_list),	\
+		.signal = quad8_signals + 2 * (_id)			\
+	},								\
+	{								\
+		.actions_list = quad8_synapse_actions_list,		\
+		.num_actions = ARRAY_SIZE(quad8_synapse_actions_list),	\
+		.signal = quad8_signals + 2 * (_id) + 1			\
+	},								\
+	{								\
+		.actions_list = quad8_index_actions_list,		\
+		.num_actions = ARRAY_SIZE(quad8_index_actions_list),	\
+		.signal = quad8_signals + 2 * (_id) + 16		\
+	}								\
+}
+
+static struct counter_synapse quad8_count_synapses[][3] = {
+	QUAD8_COUNT_SYNAPSES(0), QUAD8_COUNT_SYNAPSES(1),
+	QUAD8_COUNT_SYNAPSES(2), QUAD8_COUNT_SYNAPSES(3),
+	QUAD8_COUNT_SYNAPSES(4), QUAD8_COUNT_SYNAPSES(5),
+	QUAD8_COUNT_SYNAPSES(6), QUAD8_COUNT_SYNAPSES(7)
+};
+
+static const struct counter_count_ext quad8_count_ext[] = {
+	{
+		.name = "ceiling",
+		.read = quad8_count_ceiling_read,
+		.write = quad8_count_ceiling_write
+	},
+	{
+		.name = "floor",
+		.read = quad8_count_floor_read
+	},
+	COUNTER_COUNT_ENUM("count_mode", &quad8_cnt_mode_enum),
+	COUNTER_COUNT_ENUM_AVAILABLE("count_mode", &quad8_cnt_mode_enum),
+	{
+		.name = "direction",
+		.read = quad8_count_direction_read
+	},
+	{
+		.name = "enable",
+		.read = quad8_count_enable_read,
+		.write = quad8_count_enable_write
+	},
+	COUNTER_COUNT_ENUM("error_noise", &quad8_error_noise_enum),
+	COUNTER_COUNT_ENUM_AVAILABLE("error_noise", &quad8_error_noise_enum),
+	{
+		.name = "preset",
+		.read = quad8_count_preset_read,
+		.write = quad8_count_preset_write
+	},
+	{
+		.name = "preset_enable",
+		.read = quad8_count_preset_enable_read,
+		.write = quad8_count_preset_enable_write
+	}
+};
+
+#define QUAD8_COUNT(_id, _cntname) {					\
+	.id = (_id),							\
+	.name = (_cntname),						\
+	.functions_list = quad8_count_functions_list,			\
+	.num_functions = ARRAY_SIZE(quad8_count_functions_list),	\
+	.synapses = quad8_count_synapses[(_id)],			\
+	.num_synapses =	2,						\
+	.ext = quad8_count_ext,						\
+	.num_ext = ARRAY_SIZE(quad8_count_ext)				\
+}
+
+static struct counter_count quad8_counts[] = {
+	QUAD8_COUNT(0, "Channel 1 Count"),
+	QUAD8_COUNT(1, "Channel 2 Count"),
+	QUAD8_COUNT(2, "Channel 3 Count"),
+	QUAD8_COUNT(3, "Channel 4 Count"),
+	QUAD8_COUNT(4, "Channel 5 Count"),
+	QUAD8_COUNT(5, "Channel 6 Count"),
+	QUAD8_COUNT(6, "Channel 7 Count"),
+	QUAD8_COUNT(7, "Channel 8 Count")
+};
+
+static int quad8_probe(struct device *dev, unsigned int id)
+{
+	struct iio_dev *indio_dev;
+	struct quad8_iio *quad8iio;
+	int i, j;
+	unsigned int base_offset;
+	int err;
+
+	if (!devm_request_region(dev, base[id], QUAD8_EXTENT, dev_name(dev))) {
+		dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n",
+			base[id], base[id] + QUAD8_EXTENT);
+		return -EBUSY;
+	}
+
+	/* Allocate IIO device; this also allocates driver data structure */
+	indio_dev = devm_iio_device_alloc(dev, sizeof(*quad8iio));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	/* Initialize IIO device */
+	indio_dev->info = &quad8_info;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->num_channels = ARRAY_SIZE(quad8_channels);
+	indio_dev->channels = quad8_channels;
+	indio_dev->name = dev_name(dev);
+	indio_dev->dev.parent = dev;
+
+	/* Initialize Counter device and driver data */
+	quad8iio = iio_priv(indio_dev);
+	quad8iio->counter.name = dev_name(dev);
+	quad8iio->counter.parent = dev;
+	quad8iio->counter.ops = &quad8_ops;
+	quad8iio->counter.counts = quad8_counts;
+	quad8iio->counter.num_counts = ARRAY_SIZE(quad8_counts);
+	quad8iio->counter.signals = quad8_signals;
+	quad8iio->counter.num_signals = ARRAY_SIZE(quad8_signals);
+	quad8iio->counter.priv = quad8iio;
+	quad8iio->base = base[id];
+
+	/* Reset all counters and disable interrupt function */
+	outb(QUAD8_CHAN_OP_RESET_COUNTERS, base[id] + QUAD8_REG_CHAN_OP);
+	/* Set initial configuration for all counters */
+	for (i = 0; i < QUAD8_NUM_COUNTERS; i++) {
+		base_offset = base[id] + 2 * i;
+		/* Reset Byte Pointer */
+		outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, base_offset + 1);
+		/* Reset Preset Register */
+		for (j = 0; j < 3; j++)
+			outb(0x00, base_offset);
+		/* Reset Borrow, Carry, Compare, and Sign flags */
+		outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_FLAGS, base_offset + 1);
+		/* Reset Error flag */
+		outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_E, base_offset + 1);
+		/* Binary encoding; Normal count; non-quadrature mode */
+		outb(QUAD8_CTR_CMR, base_offset + 1);
+		/* Disable A and B inputs; preset on index; FLG1 as Carry */
+		outb(QUAD8_CTR_IOR, base_offset + 1);
+		/* Disable index function; negative index polarity */
+		outb(QUAD8_CTR_IDR, base_offset + 1);
+	}
+	/* Enable all counters */
+	outb(QUAD8_CHAN_OP_ENABLE_COUNTERS, base[id] + QUAD8_REG_CHAN_OP);
+
+	/* Register IIO device */
+	err = devm_iio_device_register(dev, indio_dev);
+	if (err)
+		return err;
+
+	/* Register Counter device */
+	return devm_counter_register(dev, &quad8iio->counter);
+}
+
+static struct isa_driver quad8_driver = {
+	.probe = quad8_probe,
+	.driver = {
+		.name = "104-quad-8"
+	}
+};
+
+module_isa_driver(quad8_driver, num_quad8);
+
+MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
+MODULE_DESCRIPTION("ACCES 104-QUAD-8 IIO driver");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/counter/Kconfig b/drivers/counter/Kconfig
new file mode 100644
index 0000000..2967d0a
--- /dev/null
+++ b/drivers/counter/Kconfig
@@ -0,0 +1,62 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Counter devices
+#
+
+menuconfig COUNTER
+	tristate "Counter support"
+	help
+	  This enables counter device support through the Generic Counter
+	  interface. You only need to enable this, if you also want to enable
+	  one or more of the counter device drivers below.
+
+if COUNTER
+
+config 104_QUAD_8
+	tristate "ACCES 104-QUAD-8 driver"
+	depends on PC104 && X86 && IIO
+	select ISA_BUS_API
+	help
+	  Say yes here to build support for the ACCES 104-QUAD-8 quadrature
+	  encoder counter/interface device family (104-QUAD-8, 104-QUAD-4).
+
+	  A counter's respective error flag may be cleared by performing a write
+	  operation on the respective count value attribute. Although the
+	  104-QUAD-8 counters have a 25-bit range, only the lower 24 bits may be
+	  set, either directly or via the counter's preset attribute. Interrupts
+	  are not supported by this driver.
+
+	  The base port addresses for the devices may be configured via the base
+	  array module parameter.
+
+config STM32_TIMER_CNT
+	tristate "STM32 Timer encoder counter driver"
+	depends on MFD_STM32_TIMERS || COMPILE_TEST
+	help
+	  Select this option to enable STM32 Timer quadrature encoder
+	  and counter driver.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called stm32-timer-cnt.
+
+config STM32_LPTIMER_CNT
+	tristate "STM32 LP Timer encoder counter driver"
+	depends on (MFD_STM32_LPTIMER || COMPILE_TEST) && IIO
+	help
+	  Select this option to enable STM32 Low-Power Timer quadrature encoder
+	  and counter driver.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called stm32-lptimer-cnt.
+
+config FTM_QUADDEC
+	tristate "Flex Timer Module Quadrature decoder driver"
+	depends on HAS_IOMEM && OF
+	help
+	  Select this option to enable the Flex Timer Quadrature decoder
+	  driver.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called ftm-quaddec.
+
+endif # COUNTER
diff --git a/drivers/counter/Makefile b/drivers/counter/Makefile
new file mode 100644
index 0000000..40d3552
--- /dev/null
+++ b/drivers/counter/Makefile
@@ -0,0 +1,11 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Makefile for Counter devices
+#
+
+obj-$(CONFIG_COUNTER) += counter.o
+
+obj-$(CONFIG_104_QUAD_8)	+= 104-quad-8.o
+obj-$(CONFIG_STM32_TIMER_CNT)	+= stm32-timer-cnt.o
+obj-$(CONFIG_STM32_LPTIMER_CNT)	+= stm32-lptimer-cnt.o
+obj-$(CONFIG_FTM_QUADDEC)	+= ftm-quaddec.o
diff --git a/drivers/counter/counter.c b/drivers/counter/counter.c
new file mode 100644
index 0000000..106bc71
--- /dev/null
+++ b/drivers/counter/counter.c
@@ -0,0 +1,1567 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Generic Counter interface
+ * Copyright (C) 2018 William Breathitt Gray
+ */
+#include <linux/counter.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/export.h>
+#include <linux/fs.h>
+#include <linux/gfp.h>
+#include <linux/idr.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/printk.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/sysfs.h>
+#include <linux/types.h>
+
+const char *const counter_count_direction_str[2] = {
+	[COUNTER_COUNT_DIRECTION_FORWARD] = "forward",
+	[COUNTER_COUNT_DIRECTION_BACKWARD] = "backward"
+};
+EXPORT_SYMBOL_GPL(counter_count_direction_str);
+
+const char *const counter_count_mode_str[4] = {
+	[COUNTER_COUNT_MODE_NORMAL] = "normal",
+	[COUNTER_COUNT_MODE_RANGE_LIMIT] = "range limit",
+	[COUNTER_COUNT_MODE_NON_RECYCLE] = "non-recycle",
+	[COUNTER_COUNT_MODE_MODULO_N] = "modulo-n"
+};
+EXPORT_SYMBOL_GPL(counter_count_mode_str);
+
+ssize_t counter_signal_enum_read(struct counter_device *counter,
+				 struct counter_signal *signal, void *priv,
+				 char *buf)
+{
+	const struct counter_signal_enum_ext *const e = priv;
+	int err;
+	size_t index;
+
+	if (!e->get)
+		return -EINVAL;
+
+	err = e->get(counter, signal, &index);
+	if (err)
+		return err;
+
+	if (index >= e->num_items)
+		return -EINVAL;
+
+	return sprintf(buf, "%s\n", e->items[index]);
+}
+EXPORT_SYMBOL_GPL(counter_signal_enum_read);
+
+ssize_t counter_signal_enum_write(struct counter_device *counter,
+				  struct counter_signal *signal, void *priv,
+				  const char *buf, size_t len)
+{
+	const struct counter_signal_enum_ext *const e = priv;
+	ssize_t index;
+	int err;
+
+	if (!e->set)
+		return -EINVAL;
+
+	index = __sysfs_match_string(e->items, e->num_items, buf);
+	if (index < 0)
+		return index;
+
+	err = e->set(counter, signal, index);
+	if (err)
+		return err;
+
+	return len;
+}
+EXPORT_SYMBOL_GPL(counter_signal_enum_write);
+
+ssize_t counter_signal_enum_available_read(struct counter_device *counter,
+					   struct counter_signal *signal,
+					   void *priv, char *buf)
+{
+	const struct counter_signal_enum_ext *const e = priv;
+	size_t i;
+	size_t len = 0;
+
+	if (!e->num_items)
+		return 0;
+
+	for (i = 0; i < e->num_items; i++)
+		len += sprintf(buf + len, "%s\n", e->items[i]);
+
+	return len;
+}
+EXPORT_SYMBOL_GPL(counter_signal_enum_available_read);
+
+ssize_t counter_count_enum_read(struct counter_device *counter,
+				struct counter_count *count, void *priv,
+				char *buf)
+{
+	const struct counter_count_enum_ext *const e = priv;
+	int err;
+	size_t index;
+
+	if (!e->get)
+		return -EINVAL;
+
+	err = e->get(counter, count, &index);
+	if (err)
+		return err;
+
+	if (index >= e->num_items)
+		return -EINVAL;
+
+	return sprintf(buf, "%s\n", e->items[index]);
+}
+EXPORT_SYMBOL_GPL(counter_count_enum_read);
+
+ssize_t counter_count_enum_write(struct counter_device *counter,
+				 struct counter_count *count, void *priv,
+				 const char *buf, size_t len)
+{
+	const struct counter_count_enum_ext *const e = priv;
+	ssize_t index;
+	int err;
+
+	if (!e->set)
+		return -EINVAL;
+
+	index = __sysfs_match_string(e->items, e->num_items, buf);
+	if (index < 0)
+		return index;
+
+	err = e->set(counter, count, index);
+	if (err)
+		return err;
+
+	return len;
+}
+EXPORT_SYMBOL_GPL(counter_count_enum_write);
+
+ssize_t counter_count_enum_available_read(struct counter_device *counter,
+					  struct counter_count *count,
+					  void *priv, char *buf)
+{
+	const struct counter_count_enum_ext *const e = priv;
+	size_t i;
+	size_t len = 0;
+
+	if (!e->num_items)
+		return 0;
+
+	for (i = 0; i < e->num_items; i++)
+		len += sprintf(buf + len, "%s\n", e->items[i]);
+
+	return len;
+}
+EXPORT_SYMBOL_GPL(counter_count_enum_available_read);
+
+ssize_t counter_device_enum_read(struct counter_device *counter, void *priv,
+				 char *buf)
+{
+	const struct counter_device_enum_ext *const e = priv;
+	int err;
+	size_t index;
+
+	if (!e->get)
+		return -EINVAL;
+
+	err = e->get(counter, &index);
+	if (err)
+		return err;
+
+	if (index >= e->num_items)
+		return -EINVAL;
+
+	return sprintf(buf, "%s\n", e->items[index]);
+}
+EXPORT_SYMBOL_GPL(counter_device_enum_read);
+
+ssize_t counter_device_enum_write(struct counter_device *counter, void *priv,
+				  const char *buf, size_t len)
+{
+	const struct counter_device_enum_ext *const e = priv;
+	ssize_t index;
+	int err;
+
+	if (!e->set)
+		return -EINVAL;
+
+	index = __sysfs_match_string(e->items, e->num_items, buf);
+	if (index < 0)
+		return index;
+
+	err = e->set(counter, index);
+	if (err)
+		return err;
+
+	return len;
+}
+EXPORT_SYMBOL_GPL(counter_device_enum_write);
+
+ssize_t counter_device_enum_available_read(struct counter_device *counter,
+					   void *priv, char *buf)
+{
+	const struct counter_device_enum_ext *const e = priv;
+	size_t i;
+	size_t len = 0;
+
+	if (!e->num_items)
+		return 0;
+
+	for (i = 0; i < e->num_items; i++)
+		len += sprintf(buf + len, "%s\n", e->items[i]);
+
+	return len;
+}
+EXPORT_SYMBOL_GPL(counter_device_enum_available_read);
+
+static const char *const counter_signal_level_str[] = {
+	[COUNTER_SIGNAL_LEVEL_LOW] = "low",
+	[COUNTER_SIGNAL_LEVEL_HIGH] = "high"
+};
+
+/**
+ * counter_signal_read_value_set - set counter_signal_read_value data
+ * @val:	counter_signal_read_value structure to set
+ * @type:	property Signal data represents
+ * @data:	Signal data
+ *
+ * This function sets an opaque counter_signal_read_value structure with the
+ * provided Signal data.
+ */
+void counter_signal_read_value_set(struct counter_signal_read_value *const val,
+				   const enum counter_signal_value_type type,
+				   void *const data)
+{
+	if (type == COUNTER_SIGNAL_LEVEL)
+		val->len = sprintf(val->buf, "%s\n",
+				   counter_signal_level_str[*(enum counter_signal_level *)data]);
+	else
+		val->len = 0;
+}
+EXPORT_SYMBOL_GPL(counter_signal_read_value_set);
+
+/**
+ * counter_count_read_value_set - set counter_count_read_value data
+ * @val:	counter_count_read_value structure to set
+ * @type:	property Count data represents
+ * @data:	Count data
+ *
+ * This function sets an opaque counter_count_read_value structure with the
+ * provided Count data.
+ */
+void counter_count_read_value_set(struct counter_count_read_value *const val,
+				  const enum counter_count_value_type type,
+				  void *const data)
+{
+	switch (type) {
+	case COUNTER_COUNT_POSITION:
+		val->len = sprintf(val->buf, "%lu\n", *(unsigned long *)data);
+		break;
+	default:
+		val->len = 0;
+	}
+}
+EXPORT_SYMBOL_GPL(counter_count_read_value_set);
+
+/**
+ * counter_count_write_value_get - get counter_count_write_value data
+ * @data:	Count data
+ * @type:	property Count data represents
+ * @val:	counter_count_write_value structure containing data
+ *
+ * This function extracts Count data from the provided opaque
+ * counter_count_write_value structure and stores it at the address provided by
+ * @data.
+ *
+ * RETURNS:
+ * 0 on success, negative error number on failure.
+ */
+int counter_count_write_value_get(void *const data,
+				  const enum counter_count_value_type type,
+				  const struct counter_count_write_value *const val)
+{
+	int err;
+
+	switch (type) {
+	case COUNTER_COUNT_POSITION:
+		err = kstrtoul(val->buf, 0, data);
+		if (err)
+			return err;
+		break;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(counter_count_write_value_get);
+
+struct counter_attr_parm {
+	struct counter_device_attr_group *group;
+	const char *prefix;
+	const char *name;
+	ssize_t (*show)(struct device *dev, struct device_attribute *attr,
+			char *buf);
+	ssize_t (*store)(struct device *dev, struct device_attribute *attr,
+			 const char *buf, size_t len);
+	void *component;
+};
+
+struct counter_device_attr {
+	struct device_attribute dev_attr;
+	struct list_head l;
+	void *component;
+};
+
+static int counter_attribute_create(const struct counter_attr_parm *const parm)
+{
+	struct counter_device_attr *counter_attr;
+	struct device_attribute *dev_attr;
+	int err;
+	struct list_head *const attr_list = &parm->group->attr_list;
+
+	/* Allocate a Counter device attribute */
+	counter_attr = kzalloc(sizeof(*counter_attr), GFP_KERNEL);
+	if (!counter_attr)
+		return -ENOMEM;
+	dev_attr = &counter_attr->dev_attr;
+
+	sysfs_attr_init(&dev_attr->attr);
+
+	/* Configure device attribute */
+	dev_attr->attr.name = kasprintf(GFP_KERNEL, "%s%s", parm->prefix,
+					parm->name);
+	if (!dev_attr->attr.name) {
+		err = -ENOMEM;
+		goto err_free_counter_attr;
+	}
+	if (parm->show) {
+		dev_attr->attr.mode |= 0444;
+		dev_attr->show = parm->show;
+	}
+	if (parm->store) {
+		dev_attr->attr.mode |= 0200;
+		dev_attr->store = parm->store;
+	}
+
+	/* Store associated Counter component with attribute */
+	counter_attr->component = parm->component;
+
+	/* Keep track of the attribute for later cleanup */
+	list_add(&counter_attr->l, attr_list);
+	parm->group->num_attr++;
+
+	return 0;
+
+err_free_counter_attr:
+	kfree(counter_attr);
+	return err;
+}
+
+#define to_counter_attr(_dev_attr) \
+	container_of(_dev_attr, struct counter_device_attr, dev_attr)
+
+struct counter_signal_unit {
+	struct counter_signal *signal;
+};
+
+static ssize_t counter_signal_show(struct device *dev,
+				   struct device_attribute *attr, char *buf)
+{
+	struct counter_device *const counter = dev_get_drvdata(dev);
+	const struct counter_device_attr *const devattr = to_counter_attr(attr);
+	const struct counter_signal_unit *const component = devattr->component;
+	struct counter_signal *const signal = component->signal;
+	int err;
+	struct counter_signal_read_value val = { .buf = buf };
+
+	err = counter->ops->signal_read(counter, signal, &val);
+	if (err)
+		return err;
+
+	return val.len;
+}
+
+struct counter_name_unit {
+	const char *name;
+};
+
+static ssize_t counter_device_attr_name_show(struct device *dev,
+					     struct device_attribute *attr,
+					     char *buf)
+{
+	const struct counter_name_unit *const comp = to_counter_attr(attr)->component;
+
+	return sprintf(buf, "%s\n", comp->name);
+}
+
+static int counter_name_attribute_create(
+	struct counter_device_attr_group *const group,
+	const char *const name)
+{
+	struct counter_name_unit *name_comp;
+	struct counter_attr_parm parm;
+	int err;
+
+	/* Skip if no name */
+	if (!name)
+		return 0;
+
+	/* Allocate name attribute component */
+	name_comp = kmalloc(sizeof(*name_comp), GFP_KERNEL);
+	if (!name_comp)
+		return -ENOMEM;
+	name_comp->name = name;
+
+	/* Allocate Signal name attribute */
+	parm.group = group;
+	parm.prefix = "";
+	parm.name = "name";
+	parm.show = counter_device_attr_name_show;
+	parm.store = NULL;
+	parm.component = name_comp;
+	err = counter_attribute_create(&parm);
+	if (err)
+		goto err_free_name_comp;
+
+	return 0;
+
+err_free_name_comp:
+	kfree(name_comp);
+	return err;
+}
+
+struct counter_signal_ext_unit {
+	struct counter_signal *signal;
+	const struct counter_signal_ext *ext;
+};
+
+static ssize_t counter_signal_ext_show(struct device *dev,
+				       struct device_attribute *attr, char *buf)
+{
+	const struct counter_device_attr *const devattr = to_counter_attr(attr);
+	const struct counter_signal_ext_unit *const comp = devattr->component;
+	const struct counter_signal_ext *const ext = comp->ext;
+
+	return ext->read(dev_get_drvdata(dev), comp->signal, ext->priv, buf);
+}
+
+static ssize_t counter_signal_ext_store(struct device *dev,
+					struct device_attribute *attr,
+					const char *buf, size_t len)
+{
+	const struct counter_device_attr *const devattr = to_counter_attr(attr);
+	const struct counter_signal_ext_unit *const comp = devattr->component;
+	const struct counter_signal_ext *const ext = comp->ext;
+
+	return ext->write(dev_get_drvdata(dev), comp->signal, ext->priv, buf,
+		len);
+}
+
+static void counter_device_attr_list_free(struct list_head *attr_list)
+{
+	struct counter_device_attr *p, *n;
+
+	list_for_each_entry_safe(p, n, attr_list, l) {
+		/* free attribute name and associated component memory */
+		kfree(p->dev_attr.attr.name);
+		kfree(p->component);
+		list_del(&p->l);
+		kfree(p);
+	}
+}
+
+static int counter_signal_ext_register(
+	struct counter_device_attr_group *const group,
+	struct counter_signal *const signal)
+{
+	const size_t num_ext = signal->num_ext;
+	size_t i;
+	const struct counter_signal_ext *ext;
+	struct counter_signal_ext_unit *signal_ext_comp;
+	struct counter_attr_parm parm;
+	int err;
+
+	/* Create an attribute for each extension */
+	for (i = 0 ; i < num_ext; i++) {
+		ext = signal->ext + i;
+
+		/* Allocate signal_ext attribute component */
+		signal_ext_comp = kmalloc(sizeof(*signal_ext_comp), GFP_KERNEL);
+		if (!signal_ext_comp) {
+			err = -ENOMEM;
+			goto err_free_attr_list;
+		}
+		signal_ext_comp->signal = signal;
+		signal_ext_comp->ext = ext;
+
+		/* Allocate a Counter device attribute */
+		parm.group = group;
+		parm.prefix = "";
+		parm.name = ext->name;
+		parm.show = (ext->read) ? counter_signal_ext_show : NULL;
+		parm.store = (ext->write) ? counter_signal_ext_store : NULL;
+		parm.component = signal_ext_comp;
+		err = counter_attribute_create(&parm);
+		if (err) {
+			kfree(signal_ext_comp);
+			goto err_free_attr_list;
+		}
+	}
+
+	return 0;
+
+err_free_attr_list:
+	counter_device_attr_list_free(&group->attr_list);
+	return err;
+}
+
+static int counter_signal_attributes_create(
+	struct counter_device_attr_group *const group,
+	const struct counter_device *const counter,
+	struct counter_signal *const signal)
+{
+	struct counter_signal_unit *signal_comp;
+	struct counter_attr_parm parm;
+	int err;
+
+	/* Allocate Signal attribute component */
+	signal_comp = kmalloc(sizeof(*signal_comp), GFP_KERNEL);
+	if (!signal_comp)
+		return -ENOMEM;
+	signal_comp->signal = signal;
+
+	/* Create main Signal attribute */
+	parm.group = group;
+	parm.prefix = "";
+	parm.name = "signal";
+	parm.show = (counter->ops->signal_read) ? counter_signal_show : NULL;
+	parm.store = NULL;
+	parm.component = signal_comp;
+	err = counter_attribute_create(&parm);
+	if (err) {
+		kfree(signal_comp);
+		return err;
+	}
+
+	/* Create Signal name attribute */
+	err = counter_name_attribute_create(group, signal->name);
+	if (err)
+		goto err_free_attr_list;
+
+	/* Register Signal extension attributes */
+	err = counter_signal_ext_register(group, signal);
+	if (err)
+		goto err_free_attr_list;
+
+	return 0;
+
+err_free_attr_list:
+	counter_device_attr_list_free(&group->attr_list);
+	return err;
+}
+
+static int counter_signals_register(
+	struct counter_device_attr_group *const groups_list,
+	const struct counter_device *const counter)
+{
+	const size_t num_signals = counter->num_signals;
+	size_t i;
+	struct counter_signal *signal;
+	const char *name;
+	int err;
+
+	/* Register each Signal */
+	for (i = 0; i < num_signals; i++) {
+		signal = counter->signals + i;
+
+		/* Generate Signal attribute directory name */
+		name = kasprintf(GFP_KERNEL, "signal%d", signal->id);
+		if (!name) {
+			err = -ENOMEM;
+			goto err_free_attr_groups;
+		}
+		groups_list[i].attr_group.name = name;
+
+		/* Create all attributes associated with Signal */
+		err = counter_signal_attributes_create(groups_list + i, counter,
+						       signal);
+		if (err)
+			goto err_free_attr_groups;
+	}
+
+	return 0;
+
+err_free_attr_groups:
+	do {
+		kfree(groups_list[i].attr_group.name);
+		counter_device_attr_list_free(&groups_list[i].attr_list);
+	} while (i--);
+	return err;
+}
+
+static const char *const counter_synapse_action_str[] = {
+	[COUNTER_SYNAPSE_ACTION_NONE] = "none",
+	[COUNTER_SYNAPSE_ACTION_RISING_EDGE] = "rising edge",
+	[COUNTER_SYNAPSE_ACTION_FALLING_EDGE] = "falling edge",
+	[COUNTER_SYNAPSE_ACTION_BOTH_EDGES] = "both edges"
+};
+
+struct counter_action_unit {
+	struct counter_synapse *synapse;
+	struct counter_count *count;
+};
+
+static ssize_t counter_action_show(struct device *dev,
+				   struct device_attribute *attr, char *buf)
+{
+	const struct counter_device_attr *const devattr = to_counter_attr(attr);
+	int err;
+	struct counter_device *const counter = dev_get_drvdata(dev);
+	const struct counter_action_unit *const component = devattr->component;
+	struct counter_count *const count = component->count;
+	struct counter_synapse *const synapse = component->synapse;
+	size_t action_index;
+	enum counter_synapse_action action;
+
+	err = counter->ops->action_get(counter, count, synapse, &action_index);
+	if (err)
+		return err;
+
+	synapse->action = action_index;
+
+	action = synapse->actions_list[action_index];
+	return sprintf(buf, "%s\n", counter_synapse_action_str[action]);
+}
+
+static ssize_t counter_action_store(struct device *dev,
+				    struct device_attribute *attr,
+				    const char *buf, size_t len)
+{
+	const struct counter_device_attr *const devattr = to_counter_attr(attr);
+	const struct counter_action_unit *const component = devattr->component;
+	struct counter_synapse *const synapse = component->synapse;
+	size_t action_index;
+	const size_t num_actions = synapse->num_actions;
+	enum counter_synapse_action action;
+	int err;
+	struct counter_device *const counter = dev_get_drvdata(dev);
+	struct counter_count *const count = component->count;
+
+	/* Find requested action mode */
+	for (action_index = 0; action_index < num_actions; action_index++) {
+		action = synapse->actions_list[action_index];
+		if (sysfs_streq(buf, counter_synapse_action_str[action]))
+			break;
+	}
+	/* If requested action mode not found */
+	if (action_index >= num_actions)
+		return -EINVAL;
+
+	err = counter->ops->action_set(counter, count, synapse, action_index);
+	if (err)
+		return err;
+
+	synapse->action = action_index;
+
+	return len;
+}
+
+struct counter_action_avail_unit {
+	const enum counter_synapse_action *actions_list;
+	size_t num_actions;
+};
+
+static ssize_t counter_synapse_action_available_show(struct device *dev,
+	struct device_attribute *attr, char *buf)
+{
+	const struct counter_device_attr *const devattr = to_counter_attr(attr);
+	const struct counter_action_avail_unit *const component = devattr->component;
+	size_t i;
+	enum counter_synapse_action action;
+	ssize_t len = 0;
+
+	for (i = 0; i < component->num_actions; i++) {
+		action = component->actions_list[i];
+		len += sprintf(buf + len, "%s\n",
+			       counter_synapse_action_str[action]);
+	}
+
+	return len;
+}
+
+static int counter_synapses_register(
+	struct counter_device_attr_group *const group,
+	const struct counter_device *const counter,
+	struct counter_count *const count, const char *const count_attr_name)
+{
+	size_t i;
+	struct counter_synapse *synapse;
+	const char *prefix;
+	struct counter_action_unit *action_comp;
+	struct counter_attr_parm parm;
+	int err;
+	struct counter_action_avail_unit *avail_comp;
+
+	/* Register each Synapse */
+	for (i = 0; i < count->num_synapses; i++) {
+		synapse = count->synapses + i;
+
+		/* Generate attribute prefix */
+		prefix = kasprintf(GFP_KERNEL, "signal%d_",
+				   synapse->signal->id);
+		if (!prefix) {
+			err = -ENOMEM;
+			goto err_free_attr_list;
+		}
+
+		/* Allocate action attribute component */
+		action_comp = kmalloc(sizeof(*action_comp), GFP_KERNEL);
+		if (!action_comp) {
+			err = -ENOMEM;
+			goto err_free_prefix;
+		}
+		action_comp->synapse = synapse;
+		action_comp->count = count;
+
+		/* Create action attribute */
+		parm.group = group;
+		parm.prefix = prefix;
+		parm.name = "action";
+		parm.show = (counter->ops->action_get) ? counter_action_show : NULL;
+		parm.store = (counter->ops->action_set) ? counter_action_store : NULL;
+		parm.component = action_comp;
+		err = counter_attribute_create(&parm);
+		if (err) {
+			kfree(action_comp);
+			goto err_free_prefix;
+		}
+
+		/* Allocate action available attribute component */
+		avail_comp = kmalloc(sizeof(*avail_comp), GFP_KERNEL);
+		if (!avail_comp) {
+			err = -ENOMEM;
+			goto err_free_prefix;
+		}
+		avail_comp->actions_list = synapse->actions_list;
+		avail_comp->num_actions = synapse->num_actions;
+
+		/* Create action_available attribute */
+		parm.group = group;
+		parm.prefix = prefix;
+		parm.name = "action_available";
+		parm.show = counter_synapse_action_available_show;
+		parm.store = NULL;
+		parm.component = avail_comp;
+		err = counter_attribute_create(&parm);
+		if (err) {
+			kfree(avail_comp);
+			goto err_free_prefix;
+		}
+
+		kfree(prefix);
+	}
+
+	return 0;
+
+err_free_prefix:
+	kfree(prefix);
+err_free_attr_list:
+	counter_device_attr_list_free(&group->attr_list);
+	return err;
+}
+
+struct counter_count_unit {
+	struct counter_count *count;
+};
+
+static ssize_t counter_count_show(struct device *dev,
+				  struct device_attribute *attr,
+				  char *buf)
+{
+	struct counter_device *const counter = dev_get_drvdata(dev);
+	const struct counter_device_attr *const devattr = to_counter_attr(attr);
+	const struct counter_count_unit *const component = devattr->component;
+	struct counter_count *const count = component->count;
+	int err;
+	struct counter_count_read_value val = { .buf = buf };
+
+	err = counter->ops->count_read(counter, count, &val);
+	if (err)
+		return err;
+
+	return val.len;
+}
+
+static ssize_t counter_count_store(struct device *dev,
+				   struct device_attribute *attr,
+				   const char *buf, size_t len)
+{
+	struct counter_device *const counter = dev_get_drvdata(dev);
+	const struct counter_device_attr *const devattr = to_counter_attr(attr);
+	const struct counter_count_unit *const component = devattr->component;
+	struct counter_count *const count = component->count;
+	int err;
+	struct counter_count_write_value val = { .buf = buf };
+
+	err = counter->ops->count_write(counter, count, &val);
+	if (err)
+		return err;
+
+	return len;
+}
+
+static const char *const counter_count_function_str[] = {
+	[COUNTER_COUNT_FUNCTION_INCREASE] = "increase",
+	[COUNTER_COUNT_FUNCTION_DECREASE] = "decrease",
+	[COUNTER_COUNT_FUNCTION_PULSE_DIRECTION] = "pulse-direction",
+	[COUNTER_COUNT_FUNCTION_QUADRATURE_X1_A] = "quadrature x1 a",
+	[COUNTER_COUNT_FUNCTION_QUADRATURE_X1_B] = "quadrature x1 b",
+	[COUNTER_COUNT_FUNCTION_QUADRATURE_X2_A] = "quadrature x2 a",
+	[COUNTER_COUNT_FUNCTION_QUADRATURE_X2_B] = "quadrature x2 b",
+	[COUNTER_COUNT_FUNCTION_QUADRATURE_X4] = "quadrature x4"
+};
+
+static ssize_t counter_function_show(struct device *dev,
+				     struct device_attribute *attr, char *buf)
+{
+	int err;
+	struct counter_device *const counter = dev_get_drvdata(dev);
+	const struct counter_device_attr *const devattr = to_counter_attr(attr);
+	const struct counter_count_unit *const component = devattr->component;
+	struct counter_count *const count = component->count;
+	size_t func_index;
+	enum counter_count_function function;
+
+	err = counter->ops->function_get(counter, count, &func_index);
+	if (err)
+		return err;
+
+	count->function = func_index;
+
+	function = count->functions_list[func_index];
+	return sprintf(buf, "%s\n", counter_count_function_str[function]);
+}
+
+static ssize_t counter_function_store(struct device *dev,
+				      struct device_attribute *attr,
+				      const char *buf, size_t len)
+{
+	const struct counter_device_attr *const devattr = to_counter_attr(attr);
+	const struct counter_count_unit *const component = devattr->component;
+	struct counter_count *const count = component->count;
+	const size_t num_functions = count->num_functions;
+	size_t func_index;
+	enum counter_count_function function;
+	int err;
+	struct counter_device *const counter = dev_get_drvdata(dev);
+
+	/* Find requested Count function mode */
+	for (func_index = 0; func_index < num_functions; func_index++) {
+		function = count->functions_list[func_index];
+		if (sysfs_streq(buf, counter_count_function_str[function]))
+			break;
+	}
+	/* Return error if requested Count function mode not found */
+	if (func_index >= num_functions)
+		return -EINVAL;
+
+	err = counter->ops->function_set(counter, count, func_index);
+	if (err)
+		return err;
+
+	count->function = func_index;
+
+	return len;
+}
+
+struct counter_count_ext_unit {
+	struct counter_count *count;
+	const struct counter_count_ext *ext;
+};
+
+static ssize_t counter_count_ext_show(struct device *dev,
+				      struct device_attribute *attr, char *buf)
+{
+	const struct counter_device_attr *const devattr = to_counter_attr(attr);
+	const struct counter_count_ext_unit *const comp = devattr->component;
+	const struct counter_count_ext *const ext = comp->ext;
+
+	return ext->read(dev_get_drvdata(dev), comp->count, ext->priv, buf);
+}
+
+static ssize_t counter_count_ext_store(struct device *dev,
+				       struct device_attribute *attr,
+				       const char *buf, size_t len)
+{
+	const struct counter_device_attr *const devattr = to_counter_attr(attr);
+	const struct counter_count_ext_unit *const comp = devattr->component;
+	const struct counter_count_ext *const ext = comp->ext;
+
+	return ext->write(dev_get_drvdata(dev), comp->count, ext->priv, buf,
+		len);
+}
+
+static int counter_count_ext_register(
+	struct counter_device_attr_group *const group,
+	struct counter_count *const count)
+{
+	size_t i;
+	const struct counter_count_ext *ext;
+	struct counter_count_ext_unit *count_ext_comp;
+	struct counter_attr_parm parm;
+	int err;
+
+	/* Create an attribute for each extension */
+	for (i = 0 ; i < count->num_ext; i++) {
+		ext = count->ext + i;
+
+		/* Allocate count_ext attribute component */
+		count_ext_comp = kmalloc(sizeof(*count_ext_comp), GFP_KERNEL);
+		if (!count_ext_comp) {
+			err = -ENOMEM;
+			goto err_free_attr_list;
+		}
+		count_ext_comp->count = count;
+		count_ext_comp->ext = ext;
+
+		/* Allocate count_ext attribute */
+		parm.group = group;
+		parm.prefix = "";
+		parm.name = ext->name;
+		parm.show = (ext->read) ? counter_count_ext_show : NULL;
+		parm.store = (ext->write) ? counter_count_ext_store : NULL;
+		parm.component = count_ext_comp;
+		err = counter_attribute_create(&parm);
+		if (err) {
+			kfree(count_ext_comp);
+			goto err_free_attr_list;
+		}
+	}
+
+	return 0;
+
+err_free_attr_list:
+	counter_device_attr_list_free(&group->attr_list);
+	return err;
+}
+
+struct counter_func_avail_unit {
+	const enum counter_count_function *functions_list;
+	size_t num_functions;
+};
+
+static ssize_t counter_count_function_available_show(struct device *dev,
+	struct device_attribute *attr, char *buf)
+{
+	const struct counter_device_attr *const devattr = to_counter_attr(attr);
+	const struct counter_func_avail_unit *const component = devattr->component;
+	const enum counter_count_function *const func_list = component->functions_list;
+	const size_t num_functions = component->num_functions;
+	size_t i;
+	enum counter_count_function function;
+	ssize_t len = 0;
+
+	for (i = 0; i < num_functions; i++) {
+		function = func_list[i];
+		len += sprintf(buf + len, "%s\n",
+			       counter_count_function_str[function]);
+	}
+
+	return len;
+}
+
+static int counter_count_attributes_create(
+	struct counter_device_attr_group *const group,
+	const struct counter_device *const counter,
+	struct counter_count *const count)
+{
+	struct counter_count_unit *count_comp;
+	struct counter_attr_parm parm;
+	int err;
+	struct counter_count_unit *func_comp;
+	struct counter_func_avail_unit *avail_comp;
+
+	/* Allocate count attribute component */
+	count_comp = kmalloc(sizeof(*count_comp), GFP_KERNEL);
+	if (!count_comp)
+		return -ENOMEM;
+	count_comp->count = count;
+
+	/* Create main Count attribute */
+	parm.group = group;
+	parm.prefix = "";
+	parm.name = "count";
+	parm.show = (counter->ops->count_read) ? counter_count_show : NULL;
+	parm.store = (counter->ops->count_write) ? counter_count_store : NULL;
+	parm.component = count_comp;
+	err = counter_attribute_create(&parm);
+	if (err) {
+		kfree(count_comp);
+		return err;
+	}
+
+	/* Allocate function attribute component */
+	func_comp = kmalloc(sizeof(*func_comp), GFP_KERNEL);
+	if (!func_comp) {
+		err = -ENOMEM;
+		goto err_free_attr_list;
+	}
+	func_comp->count = count;
+
+	/* Create Count function attribute */
+	parm.group = group;
+	parm.prefix = "";
+	parm.name = "function";
+	parm.show = (counter->ops->function_get) ? counter_function_show : NULL;
+	parm.store = (counter->ops->function_set) ? counter_function_store : NULL;
+	parm.component = func_comp;
+	err = counter_attribute_create(&parm);
+	if (err) {
+		kfree(func_comp);
+		goto err_free_attr_list;
+	}
+
+	/* Allocate function available attribute component */
+	avail_comp = kmalloc(sizeof(*avail_comp), GFP_KERNEL);
+	if (!avail_comp) {
+		err = -ENOMEM;
+		goto err_free_attr_list;
+	}
+	avail_comp->functions_list = count->functions_list;
+	avail_comp->num_functions = count->num_functions;
+
+	/* Create Count function_available attribute */
+	parm.group = group;
+	parm.prefix = "";
+	parm.name = "function_available";
+	parm.show = counter_count_function_available_show;
+	parm.store = NULL;
+	parm.component = avail_comp;
+	err = counter_attribute_create(&parm);
+	if (err) {
+		kfree(avail_comp);
+		goto err_free_attr_list;
+	}
+
+	/* Create Count name attribute */
+	err = counter_name_attribute_create(group, count->name);
+	if (err)
+		goto err_free_attr_list;
+
+	/* Register Count extension attributes */
+	err = counter_count_ext_register(group, count);
+	if (err)
+		goto err_free_attr_list;
+
+	return 0;
+
+err_free_attr_list:
+	counter_device_attr_list_free(&group->attr_list);
+	return err;
+}
+
+static int counter_counts_register(
+	struct counter_device_attr_group *const groups_list,
+	const struct counter_device *const counter)
+{
+	size_t i;
+	struct counter_count *count;
+	const char *name;
+	int err;
+
+	/* Register each Count */
+	for (i = 0; i < counter->num_counts; i++) {
+		count = counter->counts + i;
+
+		/* Generate Count attribute directory name */
+		name = kasprintf(GFP_KERNEL, "count%d", count->id);
+		if (!name) {
+			err = -ENOMEM;
+			goto err_free_attr_groups;
+		}
+		groups_list[i].attr_group.name = name;
+
+		/* Register the Synapses associated with each Count */
+		err = counter_synapses_register(groups_list + i, counter, count,
+						name);
+		if (err)
+			goto err_free_attr_groups;
+
+		/* Create all attributes associated with Count */
+		err = counter_count_attributes_create(groups_list + i, counter,
+						      count);
+		if (err)
+			goto err_free_attr_groups;
+	}
+
+	return 0;
+
+err_free_attr_groups:
+	do {
+		kfree(groups_list[i].attr_group.name);
+		counter_device_attr_list_free(&groups_list[i].attr_list);
+	} while (i--);
+	return err;
+}
+
+struct counter_size_unit {
+	size_t size;
+};
+
+static ssize_t counter_device_attr_size_show(struct device *dev,
+					     struct device_attribute *attr,
+					     char *buf)
+{
+	const struct counter_size_unit *const comp = to_counter_attr(attr)->component;
+
+	return sprintf(buf, "%zu\n", comp->size);
+}
+
+static int counter_size_attribute_create(
+	struct counter_device_attr_group *const group,
+	const size_t size, const char *const name)
+{
+	struct counter_size_unit *size_comp;
+	struct counter_attr_parm parm;
+	int err;
+
+	/* Allocate size attribute component */
+	size_comp = kmalloc(sizeof(*size_comp), GFP_KERNEL);
+	if (!size_comp)
+		return -ENOMEM;
+	size_comp->size = size;
+
+	parm.group = group;
+	parm.prefix = "";
+	parm.name = name;
+	parm.show = counter_device_attr_size_show;
+	parm.store = NULL;
+	parm.component = size_comp;
+	err = counter_attribute_create(&parm);
+	if (err)
+		goto err_free_size_comp;
+
+	return 0;
+
+err_free_size_comp:
+	kfree(size_comp);
+	return err;
+}
+
+struct counter_ext_unit {
+	const struct counter_device_ext *ext;
+};
+
+static ssize_t counter_device_ext_show(struct device *dev,
+				       struct device_attribute *attr, char *buf)
+{
+	const struct counter_device_attr *const devattr = to_counter_attr(attr);
+	const struct counter_ext_unit *const component = devattr->component;
+	const struct counter_device_ext *const ext = component->ext;
+
+	return ext->read(dev_get_drvdata(dev), ext->priv, buf);
+}
+
+static ssize_t counter_device_ext_store(struct device *dev,
+					struct device_attribute *attr,
+					const char *buf, size_t len)
+{
+	const struct counter_device_attr *const devattr = to_counter_attr(attr);
+	const struct counter_ext_unit *const component = devattr->component;
+	const struct counter_device_ext *const ext = component->ext;
+
+	return ext->write(dev_get_drvdata(dev), ext->priv, buf, len);
+}
+
+static int counter_device_ext_register(
+	struct counter_device_attr_group *const group,
+	struct counter_device *const counter)
+{
+	size_t i;
+	struct counter_ext_unit *ext_comp;
+	struct counter_attr_parm parm;
+	int err;
+
+	/* Create an attribute for each extension */
+	for (i = 0 ; i < counter->num_ext; i++) {
+		/* Allocate extension attribute component */
+		ext_comp = kmalloc(sizeof(*ext_comp), GFP_KERNEL);
+		if (!ext_comp) {
+			err = -ENOMEM;
+			goto err_free_attr_list;
+		}
+
+		ext_comp->ext = counter->ext + i;
+
+		/* Allocate extension attribute */
+		parm.group = group;
+		parm.prefix = "";
+		parm.name = counter->ext[i].name;
+		parm.show = (counter->ext[i].read) ? counter_device_ext_show : NULL;
+		parm.store = (counter->ext[i].write) ? counter_device_ext_store : NULL;
+		parm.component = ext_comp;
+		err = counter_attribute_create(&parm);
+		if (err) {
+			kfree(ext_comp);
+			goto err_free_attr_list;
+		}
+	}
+
+	return 0;
+
+err_free_attr_list:
+	counter_device_attr_list_free(&group->attr_list);
+	return err;
+}
+
+static int counter_global_attr_register(
+	struct counter_device_attr_group *const group,
+	struct counter_device *const counter)
+{
+	int err;
+
+	/* Create name attribute */
+	err = counter_name_attribute_create(group, counter->name);
+	if (err)
+		return err;
+
+	/* Create num_counts attribute */
+	err = counter_size_attribute_create(group, counter->num_counts,
+					    "num_counts");
+	if (err)
+		goto err_free_attr_list;
+
+	/* Create num_signals attribute */
+	err = counter_size_attribute_create(group, counter->num_signals,
+					    "num_signals");
+	if (err)
+		goto err_free_attr_list;
+
+	/* Register Counter device extension attributes */
+	err = counter_device_ext_register(group, counter);
+	if (err)
+		goto err_free_attr_list;
+
+	return 0;
+
+err_free_attr_list:
+	counter_device_attr_list_free(&group->attr_list);
+	return err;
+}
+
+static void counter_device_groups_list_free(
+	struct counter_device_attr_group *const groups_list,
+	const size_t num_groups)
+{
+	struct counter_device_attr_group *group;
+	size_t i;
+
+	/* loop through all attribute groups (signals, counts, global, etc.) */
+	for (i = 0; i < num_groups; i++) {
+		group = groups_list + i;
+
+		/* free all attribute group and associated attributes memory */
+		kfree(group->attr_group.name);
+		kfree(group->attr_group.attrs);
+		counter_device_attr_list_free(&group->attr_list);
+	}
+
+	kfree(groups_list);
+}
+
+static int counter_device_groups_list_prepare(
+	struct counter_device *const counter)
+{
+	const size_t total_num_groups =
+		counter->num_signals + counter->num_counts + 1;
+	struct counter_device_attr_group *groups_list;
+	size_t i;
+	int err;
+	size_t num_groups = 0;
+
+	/* Allocate space for attribute groups (signals, counts, and ext) */
+	groups_list = kcalloc(total_num_groups, sizeof(*groups_list),
+			      GFP_KERNEL);
+	if (!groups_list)
+		return -ENOMEM;
+
+	/* Initialize attribute lists */
+	for (i = 0; i < total_num_groups; i++)
+		INIT_LIST_HEAD(&groups_list[i].attr_list);
+
+	/* Register Signals */
+	err = counter_signals_register(groups_list, counter);
+	if (err)
+		goto err_free_groups_list;
+	num_groups += counter->num_signals;
+
+	/* Register Counts and respective Synapses */
+	err = counter_counts_register(groups_list + num_groups, counter);
+	if (err)
+		goto err_free_groups_list;
+	num_groups += counter->num_counts;
+
+	/* Register Counter global attributes */
+	err = counter_global_attr_register(groups_list + num_groups, counter);
+	if (err)
+		goto err_free_groups_list;
+	num_groups++;
+
+	/* Store groups_list in device_state */
+	counter->device_state->groups_list = groups_list;
+	counter->device_state->num_groups = num_groups;
+
+	return 0;
+
+err_free_groups_list:
+	counter_device_groups_list_free(groups_list, num_groups);
+	return err;
+}
+
+static int counter_device_groups_prepare(
+	struct counter_device_state *const device_state)
+{
+	size_t i, j;
+	struct counter_device_attr_group *group;
+	int err;
+	struct counter_device_attr *p;
+
+	/* Allocate attribute groups for association with device */
+	device_state->groups = kcalloc(device_state->num_groups + 1,
+				       sizeof(*device_state->groups),
+				       GFP_KERNEL);
+	if (!device_state->groups)
+		return -ENOMEM;
+
+	/* Prepare each group of attributes for association */
+	for (i = 0; i < device_state->num_groups; i++) {
+		group = device_state->groups_list + i;
+
+		/* Allocate space for attribute pointers in attribute group */
+		group->attr_group.attrs = kcalloc(group->num_attr + 1,
+			sizeof(*group->attr_group.attrs), GFP_KERNEL);
+		if (!group->attr_group.attrs) {
+			err = -ENOMEM;
+			goto err_free_groups;
+		}
+
+		/* Add attribute pointers to attribute group */
+		j = 0;
+		list_for_each_entry(p, &group->attr_list, l)
+			group->attr_group.attrs[j++] = &p->dev_attr.attr;
+
+		/* Group attributes in attribute group */
+		device_state->groups[i] = &group->attr_group;
+	}
+	/* Associate attributes with device */
+	device_state->dev.groups = device_state->groups;
+
+	return 0;
+
+err_free_groups:
+	do {
+		group = device_state->groups_list + i;
+		kfree(group->attr_group.attrs);
+		group->attr_group.attrs = NULL;
+	} while (i--);
+	kfree(device_state->groups);
+	return err;
+}
+
+/* Provides a unique ID for each counter device */
+static DEFINE_IDA(counter_ida);
+
+static void counter_device_release(struct device *dev)
+{
+	struct counter_device *const counter = dev_get_drvdata(dev);
+	struct counter_device_state *const device_state = counter->device_state;
+
+	kfree(device_state->groups);
+	counter_device_groups_list_free(device_state->groups_list,
+					device_state->num_groups);
+	ida_simple_remove(&counter_ida, device_state->id);
+	kfree(device_state);
+}
+
+static struct device_type counter_device_type = {
+	.name = "counter_device",
+	.release = counter_device_release
+};
+
+static struct bus_type counter_bus_type = {
+	.name = "counter"
+};
+
+/**
+ * counter_register - register Counter to the system
+ * @counter:	pointer to Counter to register
+ *
+ * This function registers a Counter to the system. A sysfs "counter" directory
+ * will be created and populated with sysfs attributes correlating with the
+ * Counter Signals, Synapses, and Counts respectively.
+ */
+int counter_register(struct counter_device *const counter)
+{
+	struct counter_device_state *device_state;
+	int err;
+
+	/* Allocate internal state container for Counter device */
+	device_state = kzalloc(sizeof(*device_state), GFP_KERNEL);
+	if (!device_state)
+		return -ENOMEM;
+	counter->device_state = device_state;
+
+	/* Acquire unique ID */
+	device_state->id = ida_simple_get(&counter_ida, 0, 0, GFP_KERNEL);
+	if (device_state->id < 0) {
+		err = device_state->id;
+		goto err_free_device_state;
+	}
+
+	/* Configure device structure for Counter */
+	device_state->dev.type = &counter_device_type;
+	device_state->dev.bus = &counter_bus_type;
+	if (counter->parent) {
+		device_state->dev.parent = counter->parent;
+		device_state->dev.of_node = counter->parent->of_node;
+	}
+	dev_set_name(&device_state->dev, "counter%d", device_state->id);
+	device_initialize(&device_state->dev);
+	dev_set_drvdata(&device_state->dev, counter);
+
+	/* Prepare device attributes */
+	err = counter_device_groups_list_prepare(counter);
+	if (err)
+		goto err_free_id;
+
+	/* Organize device attributes to groups and match to device */
+	err = counter_device_groups_prepare(device_state);
+	if (err)
+		goto err_free_groups_list;
+
+	/* Add device to system */
+	err = device_add(&device_state->dev);
+	if (err)
+		goto err_free_groups;
+
+	return 0;
+
+err_free_groups:
+	kfree(device_state->groups);
+err_free_groups_list:
+	counter_device_groups_list_free(device_state->groups_list,
+					device_state->num_groups);
+err_free_id:
+	ida_simple_remove(&counter_ida, device_state->id);
+err_free_device_state:
+	kfree(device_state);
+	return err;
+}
+EXPORT_SYMBOL_GPL(counter_register);
+
+/**
+ * counter_unregister - unregister Counter from the system
+ * @counter:	pointer to Counter to unregister
+ *
+ * The Counter is unregistered from the system; all allocated memory is freed.
+ */
+void counter_unregister(struct counter_device *const counter)
+{
+	if (counter)
+		device_del(&counter->device_state->dev);
+}
+EXPORT_SYMBOL_GPL(counter_unregister);
+
+static void devm_counter_unreg(struct device *dev, void *res)
+{
+	counter_unregister(*(struct counter_device **)res);
+}
+
+/**
+ * devm_counter_register - Resource-managed counter_register
+ * @dev:	device to allocate counter_device for
+ * @counter:	pointer to Counter to register
+ *
+ * Managed counter_register. The Counter registered with this function is
+ * automatically unregistered on driver detach. This function calls
+ * counter_register internally. Refer to that function for more information.
+ *
+ * If an Counter registered with this function needs to be unregistered
+ * separately, devm_counter_unregister must be used.
+ *
+ * RETURNS:
+ * 0 on success, negative error number on failure.
+ */
+int devm_counter_register(struct device *dev,
+			  struct counter_device *const counter)
+{
+	struct counter_device **ptr;
+	int ret;
+
+	ptr = devres_alloc(devm_counter_unreg, sizeof(*ptr), GFP_KERNEL);
+	if (!ptr)
+		return -ENOMEM;
+
+	ret = counter_register(counter);
+	if (!ret) {
+		*ptr = counter;
+		devres_add(dev, ptr);
+	} else {
+		devres_free(ptr);
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(devm_counter_register);
+
+static int devm_counter_match(struct device *dev, void *res, void *data)
+{
+	struct counter_device **r = res;
+
+	if (!r || !*r) {
+		WARN_ON(!r || !*r);
+		return 0;
+	}
+
+	return *r == data;
+}
+
+/**
+ * devm_counter_unregister - Resource-managed counter_unregister
+ * @dev:	device this counter_device belongs to
+ * @counter:	pointer to Counter associated with the device
+ *
+ * Unregister Counter registered with devm_counter_register.
+ */
+void devm_counter_unregister(struct device *dev,
+			     struct counter_device *const counter)
+{
+	int rc;
+
+	rc = devres_release(dev, devm_counter_unreg, devm_counter_match,
+			    counter);
+	WARN_ON(rc);
+}
+EXPORT_SYMBOL_GPL(devm_counter_unregister);
+
+static int __init counter_init(void)
+{
+	return bus_register(&counter_bus_type);
+}
+
+static void __exit counter_exit(void)
+{
+	bus_unregister(&counter_bus_type);
+}
+
+subsys_initcall(counter_init);
+module_exit(counter_exit);
+
+MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
+MODULE_DESCRIPTION("Generic Counter interface");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/counter/ftm-quaddec.c b/drivers/counter/ftm-quaddec.c
new file mode 100644
index 0000000..4046aa9
--- /dev/null
+++ b/drivers/counter/ftm-quaddec.c
@@ -0,0 +1,350 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Flex Timer Module Quadrature decoder
+ *
+ * This module implements a driver for decoding the FTM quadrature
+ * of ex. a LS1021A
+ */
+
+#include <linux/fsl/ftm.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/of.h>
+#include <linux/io.h>
+#include <linux/mutex.h>
+#include <linux/counter.h>
+#include <linux/bitfield.h>
+
+#define FTM_FIELD_UPDATE(ftm, offset, mask, val)			\
+	({								\
+		uint32_t flags;						\
+		ftm_read(ftm, offset, &flags);				\
+		flags &= ~mask;						\
+		flags |= FIELD_PREP(mask, val);				\
+		ftm_write(ftm, offset, flags);				\
+	})
+
+struct ftm_quaddec {
+	struct counter_device counter;
+	struct platform_device *pdev;
+	void __iomem *ftm_base;
+	bool big_endian;
+	struct mutex ftm_quaddec_mutex;
+};
+
+static void ftm_read(struct ftm_quaddec *ftm, uint32_t offset, uint32_t *data)
+{
+	if (ftm->big_endian)
+		*data = ioread32be(ftm->ftm_base + offset);
+	else
+		*data = ioread32(ftm->ftm_base + offset);
+}
+
+static void ftm_write(struct ftm_quaddec *ftm, uint32_t offset, uint32_t data)
+{
+	if (ftm->big_endian)
+		iowrite32be(data, ftm->ftm_base + offset);
+	else
+		iowrite32(data, ftm->ftm_base + offset);
+}
+
+/* Hold mutex before modifying write protection state */
+static void ftm_clear_write_protection(struct ftm_quaddec *ftm)
+{
+	uint32_t flag;
+
+	/* First see if it is enabled */
+	ftm_read(ftm, FTM_FMS, &flag);
+
+	if (flag & FTM_FMS_WPEN)
+		FTM_FIELD_UPDATE(ftm, FTM_MODE, FTM_MODE_WPDIS, 1);
+}
+
+static void ftm_set_write_protection(struct ftm_quaddec *ftm)
+{
+	FTM_FIELD_UPDATE(ftm, FTM_FMS, FTM_FMS_WPEN, 1);
+}
+
+static void ftm_reset_counter(struct ftm_quaddec *ftm)
+{
+	/* Reset hardware counter to CNTIN */
+	ftm_write(ftm, FTM_CNT, 0x0);
+}
+
+static void ftm_quaddec_init(struct ftm_quaddec *ftm)
+{
+	ftm_clear_write_protection(ftm);
+
+	/*
+	 * Do not write in the region from the CNTIN register through the
+	 * PWMLOAD register when FTMEN = 0.
+	 * Also reset other fields to zero
+	 */
+	ftm_write(ftm, FTM_MODE, FTM_MODE_FTMEN);
+	ftm_write(ftm, FTM_CNTIN, 0x0000);
+	ftm_write(ftm, FTM_MOD, 0xffff);
+	ftm_write(ftm, FTM_CNT, 0x0);
+	/* Set prescaler, reset other fields to zero */
+	ftm_write(ftm, FTM_SC, FTM_SC_PS_1);
+
+	/* Select quad mode, reset other fields to zero */
+	ftm_write(ftm, FTM_QDCTRL, FTM_QDCTRL_QUADEN);
+
+	/* Unused features and reset to default section */
+	ftm_write(ftm, FTM_POL, 0x0);
+	ftm_write(ftm, FTM_FLTCTRL, 0x0);
+	ftm_write(ftm, FTM_SYNCONF, 0x0);
+	ftm_write(ftm, FTM_SYNC, 0xffff);
+
+	/* Lock the FTM */
+	ftm_set_write_protection(ftm);
+}
+
+static void ftm_quaddec_disable(void *ftm)
+{
+	struct ftm_quaddec *ftm_qua = ftm;
+
+	ftm_clear_write_protection(ftm_qua);
+	ftm_write(ftm_qua, FTM_MODE, 0);
+	ftm_write(ftm_qua, FTM_QDCTRL, 0);
+	/*
+	 * This is enough to disable the counter. No clock has been
+	 * selected by writing to FTM_SC in init()
+	 */
+	ftm_set_write_protection(ftm_qua);
+}
+
+static int ftm_quaddec_get_prescaler(struct counter_device *counter,
+				     struct counter_count *count,
+				     size_t *cnt_mode)
+{
+	struct ftm_quaddec *ftm = counter->priv;
+	uint32_t scflags;
+
+	ftm_read(ftm, FTM_SC, &scflags);
+
+	*cnt_mode = FIELD_GET(FTM_SC_PS_MASK, scflags);
+
+	return 0;
+}
+
+static int ftm_quaddec_set_prescaler(struct counter_device *counter,
+				     struct counter_count *count,
+				     size_t cnt_mode)
+{
+	struct ftm_quaddec *ftm = counter->priv;
+
+	mutex_lock(&ftm->ftm_quaddec_mutex);
+
+	ftm_clear_write_protection(ftm);
+	FTM_FIELD_UPDATE(ftm, FTM_SC, FTM_SC_PS_MASK, cnt_mode);
+	ftm_set_write_protection(ftm);
+
+	/* Also resets the counter as it is undefined anyway now */
+	ftm_reset_counter(ftm);
+
+	mutex_unlock(&ftm->ftm_quaddec_mutex);
+	return 0;
+}
+
+static const char * const ftm_quaddec_prescaler[] = {
+	"1", "2", "4", "8", "16", "32", "64", "128"
+};
+
+static struct counter_count_enum_ext ftm_quaddec_prescaler_enum = {
+	.items = ftm_quaddec_prescaler,
+	.num_items = ARRAY_SIZE(ftm_quaddec_prescaler),
+	.get = ftm_quaddec_get_prescaler,
+	.set = ftm_quaddec_set_prescaler
+};
+
+enum ftm_quaddec_synapse_action {
+	FTM_QUADDEC_SYNAPSE_ACTION_BOTH_EDGES,
+};
+
+static enum counter_synapse_action ftm_quaddec_synapse_actions[] = {
+	[FTM_QUADDEC_SYNAPSE_ACTION_BOTH_EDGES] =
+	COUNTER_SYNAPSE_ACTION_BOTH_EDGES
+};
+
+enum ftm_quaddec_count_function {
+	FTM_QUADDEC_COUNT_ENCODER_MODE_1,
+};
+
+static const enum counter_count_function ftm_quaddec_count_functions[] = {
+	[FTM_QUADDEC_COUNT_ENCODER_MODE_1] =
+	COUNTER_COUNT_FUNCTION_QUADRATURE_X4
+};
+
+static int ftm_quaddec_count_read(struct counter_device *counter,
+				  struct counter_count *count,
+				  struct counter_count_read_value *val)
+{
+	struct ftm_quaddec *const ftm = counter->priv;
+	uint32_t cntval;
+
+	ftm_read(ftm, FTM_CNT, &cntval);
+
+	counter_count_read_value_set(val, COUNTER_COUNT_POSITION, &cntval);
+
+	return 0;
+}
+
+static int ftm_quaddec_count_write(struct counter_device *counter,
+				   struct counter_count *count,
+				   struct counter_count_write_value *val)
+{
+	struct ftm_quaddec *const ftm = counter->priv;
+	u32 cnt;
+	int err;
+
+	err = counter_count_write_value_get(&cnt, COUNTER_COUNT_POSITION, val);
+	if (err)
+		return err;
+
+	if (cnt != 0) {
+		dev_warn(&ftm->pdev->dev, "Can only accept '0' as new counter value\n");
+		return -EINVAL;
+	}
+
+	ftm_reset_counter(ftm);
+
+	return 0;
+}
+
+static int ftm_quaddec_count_function_get(struct counter_device *counter,
+					  struct counter_count *count,
+					  size_t *function)
+{
+	*function = FTM_QUADDEC_COUNT_ENCODER_MODE_1;
+
+	return 0;
+}
+
+static int ftm_quaddec_action_get(struct counter_device *counter,
+				  struct counter_count *count,
+				  struct counter_synapse *synapse,
+				  size_t *action)
+{
+	*action = FTM_QUADDEC_SYNAPSE_ACTION_BOTH_EDGES;
+
+	return 0;
+}
+
+static const struct counter_ops ftm_quaddec_cnt_ops = {
+	.count_read = ftm_quaddec_count_read,
+	.count_write = ftm_quaddec_count_write,
+	.function_get = ftm_quaddec_count_function_get,
+	.action_get = ftm_quaddec_action_get,
+};
+
+static struct counter_signal ftm_quaddec_signals[] = {
+	{
+		.id = 0,
+		.name = "Channel 1 Phase A"
+	},
+	{
+		.id = 1,
+		.name = "Channel 1 Phase B"
+	}
+};
+
+static struct counter_synapse ftm_quaddec_count_synapses[] = {
+	{
+		.actions_list = ftm_quaddec_synapse_actions,
+		.num_actions = ARRAY_SIZE(ftm_quaddec_synapse_actions),
+		.signal = &ftm_quaddec_signals[0]
+	},
+	{
+		.actions_list = ftm_quaddec_synapse_actions,
+		.num_actions = ARRAY_SIZE(ftm_quaddec_synapse_actions),
+		.signal = &ftm_quaddec_signals[1]
+	}
+};
+
+static const struct counter_count_ext ftm_quaddec_count_ext[] = {
+	COUNTER_COUNT_ENUM("prescaler", &ftm_quaddec_prescaler_enum),
+	COUNTER_COUNT_ENUM_AVAILABLE("prescaler", &ftm_quaddec_prescaler_enum),
+};
+
+static struct counter_count ftm_quaddec_counts = {
+	.id = 0,
+	.name = "Channel 1 Count",
+	.functions_list = ftm_quaddec_count_functions,
+	.num_functions = ARRAY_SIZE(ftm_quaddec_count_functions),
+	.synapses = ftm_quaddec_count_synapses,
+	.num_synapses = ARRAY_SIZE(ftm_quaddec_count_synapses),
+	.ext = ftm_quaddec_count_ext,
+	.num_ext = ARRAY_SIZE(ftm_quaddec_count_ext)
+};
+
+static int ftm_quaddec_probe(struct platform_device *pdev)
+{
+	struct ftm_quaddec *ftm;
+
+	struct device_node *node = pdev->dev.of_node;
+	struct resource *io;
+	int ret;
+
+	ftm = devm_kzalloc(&pdev->dev, sizeof(*ftm), GFP_KERNEL);
+	if (!ftm)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, ftm);
+
+	io = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!io) {
+		dev_err(&pdev->dev, "Failed to get memory region\n");
+		return -ENODEV;
+	}
+
+	ftm->pdev = pdev;
+	ftm->big_endian = of_property_read_bool(node, "big-endian");
+	ftm->ftm_base = devm_ioremap(&pdev->dev, io->start, resource_size(io));
+
+	if (!ftm->ftm_base) {
+		dev_err(&pdev->dev, "Failed to map memory region\n");
+		return -EINVAL;
+	}
+	ftm->counter.name = dev_name(&pdev->dev);
+	ftm->counter.parent = &pdev->dev;
+	ftm->counter.ops = &ftm_quaddec_cnt_ops;
+	ftm->counter.counts = &ftm_quaddec_counts;
+	ftm->counter.num_counts = 1;
+	ftm->counter.signals = ftm_quaddec_signals;
+	ftm->counter.num_signals = ARRAY_SIZE(ftm_quaddec_signals);
+	ftm->counter.priv = ftm;
+
+	mutex_init(&ftm->ftm_quaddec_mutex);
+
+	ftm_quaddec_init(ftm);
+
+	ret = devm_add_action_or_reset(&pdev->dev, ftm_quaddec_disable, ftm);
+	if (ret)
+		return ret;
+
+	ret = devm_counter_register(&pdev->dev, &ftm->counter);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static const struct of_device_id ftm_quaddec_match[] = {
+	{ .compatible = "fsl,ftm-quaddec" },
+	{},
+};
+
+static struct platform_driver ftm_quaddec_driver = {
+	.driver = {
+		.name = "ftm-quaddec",
+		.of_match_table = ftm_quaddec_match,
+	},
+	.probe = ftm_quaddec_probe,
+};
+
+module_platform_driver(ftm_quaddec_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Kjeld Flarup <kfa@deif.com>");
+MODULE_AUTHOR("Patrick Havelange <patrick.havelange@essensium.com>");
diff --git a/drivers/counter/stm32-lptimer-cnt.c b/drivers/counter/stm32-lptimer-cnt.c
new file mode 100644
index 0000000..bbc930a
--- /dev/null
+++ b/drivers/counter/stm32-lptimer-cnt.c
@@ -0,0 +1,754 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * STM32 Low-Power Timer Encoder and Counter driver
+ *
+ * Copyright (C) STMicroelectronics 2017
+ *
+ * Author: Fabrice Gasnier <fabrice.gasnier@st.com>
+ *
+ * Inspired by 104-quad-8 and stm32-timer-trigger drivers.
+ *
+ */
+
+#include <linux/bitfield.h>
+#include <linux/counter.h>
+#include <linux/iio/iio.h>
+#include <linux/mfd/stm32-lptimer.h>
+#include <linux/module.h>
+#include <linux/pinctrl/consumer.h>
+#include <linux/platform_device.h>
+
+struct stm32_lptim_cnt {
+	struct counter_device counter;
+	struct device *dev;
+	struct regmap *regmap;
+	struct clk *clk;
+	u32 ceiling;
+	u32 polarity;
+	u32 quadrature_mode;
+	bool enabled;
+};
+
+static int stm32_lptim_is_enabled(struct stm32_lptim_cnt *priv)
+{
+	u32 val;
+	int ret;
+
+	ret = regmap_read(priv->regmap, STM32_LPTIM_CR, &val);
+	if (ret)
+		return ret;
+
+	return FIELD_GET(STM32_LPTIM_ENABLE, val);
+}
+
+static int stm32_lptim_set_enable_state(struct stm32_lptim_cnt *priv,
+					int enable)
+{
+	int ret;
+	u32 val;
+
+	val = FIELD_PREP(STM32_LPTIM_ENABLE, enable);
+	ret = regmap_write(priv->regmap, STM32_LPTIM_CR, val);
+	if (ret)
+		return ret;
+
+	if (!enable) {
+		clk_disable(priv->clk);
+		priv->enabled = false;
+		return 0;
+	}
+
+	/* LP timer must be enabled before writing CMP & ARR */
+	ret = regmap_write(priv->regmap, STM32_LPTIM_ARR, priv->ceiling);
+	if (ret)
+		return ret;
+
+	ret = regmap_write(priv->regmap, STM32_LPTIM_CMP, 0);
+	if (ret)
+		return ret;
+
+	/* ensure CMP & ARR registers are properly written */
+	ret = regmap_read_poll_timeout(priv->regmap, STM32_LPTIM_ISR, val,
+				       (val & STM32_LPTIM_CMPOK_ARROK),
+				       100, 1000);
+	if (ret)
+		return ret;
+
+	ret = regmap_write(priv->regmap, STM32_LPTIM_ICR,
+			   STM32_LPTIM_CMPOKCF_ARROKCF);
+	if (ret)
+		return ret;
+
+	ret = clk_enable(priv->clk);
+	if (ret) {
+		regmap_write(priv->regmap, STM32_LPTIM_CR, 0);
+		return ret;
+	}
+	priv->enabled = true;
+
+	/* Start LP timer in continuous mode */
+	return regmap_update_bits(priv->regmap, STM32_LPTIM_CR,
+				  STM32_LPTIM_CNTSTRT, STM32_LPTIM_CNTSTRT);
+}
+
+static int stm32_lptim_setup(struct stm32_lptim_cnt *priv, int enable)
+{
+	u32 mask = STM32_LPTIM_ENC | STM32_LPTIM_COUNTMODE |
+		   STM32_LPTIM_CKPOL | STM32_LPTIM_PRESC;
+	u32 val;
+
+	/* Setup LP timer encoder/counter and polarity, without prescaler */
+	if (priv->quadrature_mode)
+		val = enable ? STM32_LPTIM_ENC : 0;
+	else
+		val = enable ? STM32_LPTIM_COUNTMODE : 0;
+	val |= FIELD_PREP(STM32_LPTIM_CKPOL, enable ? priv->polarity : 0);
+
+	return regmap_update_bits(priv->regmap, STM32_LPTIM_CFGR, mask, val);
+}
+
+static int stm32_lptim_write_raw(struct iio_dev *indio_dev,
+				 struct iio_chan_spec const *chan,
+				 int val, int val2, long mask)
+{
+	struct stm32_lptim_cnt *priv = iio_priv(indio_dev);
+	int ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_ENABLE:
+		if (val < 0 || val > 1)
+			return -EINVAL;
+
+		/* Check nobody uses the timer, or already disabled/enabled */
+		ret = stm32_lptim_is_enabled(priv);
+		if ((ret < 0) || (!ret && !val))
+			return ret;
+		if (val && ret)
+			return -EBUSY;
+
+		ret = stm32_lptim_setup(priv, val);
+		if (ret)
+			return ret;
+		return stm32_lptim_set_enable_state(priv, val);
+
+	default:
+		return -EINVAL;
+	}
+}
+
+static int stm32_lptim_read_raw(struct iio_dev *indio_dev,
+				struct iio_chan_spec const *chan,
+				int *val, int *val2, long mask)
+{
+	struct stm32_lptim_cnt *priv = iio_priv(indio_dev);
+	u32 dat;
+	int ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		ret = regmap_read(priv->regmap, STM32_LPTIM_CNT, &dat);
+		if (ret)
+			return ret;
+		*val = dat;
+		return IIO_VAL_INT;
+
+	case IIO_CHAN_INFO_ENABLE:
+		ret = stm32_lptim_is_enabled(priv);
+		if (ret < 0)
+			return ret;
+		*val = ret;
+		return IIO_VAL_INT;
+
+	case IIO_CHAN_INFO_SCALE:
+		/* Non-quadrature mode: scale = 1 */
+		*val = 1;
+		*val2 = 0;
+		if (priv->quadrature_mode) {
+			/*
+			 * Quadrature encoder mode:
+			 * - both edges, quarter cycle, scale is 0.25
+			 * - either rising/falling edge scale is 0.5
+			 */
+			if (priv->polarity > 1)
+				*val2 = 2;
+			else
+				*val2 = 1;
+		}
+		return IIO_VAL_FRACTIONAL_LOG2;
+
+	default:
+		return -EINVAL;
+	}
+}
+
+static const struct iio_info stm32_lptim_cnt_iio_info = {
+	.read_raw = stm32_lptim_read_raw,
+	.write_raw = stm32_lptim_write_raw,
+};
+
+static const char *const stm32_lptim_quadrature_modes[] = {
+	"non-quadrature",
+	"quadrature",
+};
+
+static int stm32_lptim_get_quadrature_mode(struct iio_dev *indio_dev,
+					   const struct iio_chan_spec *chan)
+{
+	struct stm32_lptim_cnt *priv = iio_priv(indio_dev);
+
+	return priv->quadrature_mode;
+}
+
+static int stm32_lptim_set_quadrature_mode(struct iio_dev *indio_dev,
+					   const struct iio_chan_spec *chan,
+					   unsigned int type)
+{
+	struct stm32_lptim_cnt *priv = iio_priv(indio_dev);
+
+	if (stm32_lptim_is_enabled(priv))
+		return -EBUSY;
+
+	priv->quadrature_mode = type;
+
+	return 0;
+}
+
+static const struct iio_enum stm32_lptim_quadrature_mode_en = {
+	.items = stm32_lptim_quadrature_modes,
+	.num_items = ARRAY_SIZE(stm32_lptim_quadrature_modes),
+	.get = stm32_lptim_get_quadrature_mode,
+	.set = stm32_lptim_set_quadrature_mode,
+};
+
+static const char * const stm32_lptim_cnt_polarity[] = {
+	"rising-edge", "falling-edge", "both-edges",
+};
+
+static int stm32_lptim_cnt_get_polarity(struct iio_dev *indio_dev,
+					const struct iio_chan_spec *chan)
+{
+	struct stm32_lptim_cnt *priv = iio_priv(indio_dev);
+
+	return priv->polarity;
+}
+
+static int stm32_lptim_cnt_set_polarity(struct iio_dev *indio_dev,
+					const struct iio_chan_spec *chan,
+					unsigned int type)
+{
+	struct stm32_lptim_cnt *priv = iio_priv(indio_dev);
+
+	if (stm32_lptim_is_enabled(priv))
+		return -EBUSY;
+
+	priv->polarity = type;
+
+	return 0;
+}
+
+static const struct iio_enum stm32_lptim_cnt_polarity_en = {
+	.items = stm32_lptim_cnt_polarity,
+	.num_items = ARRAY_SIZE(stm32_lptim_cnt_polarity),
+	.get = stm32_lptim_cnt_get_polarity,
+	.set = stm32_lptim_cnt_set_polarity,
+};
+
+static ssize_t stm32_lptim_cnt_get_ceiling(struct stm32_lptim_cnt *priv,
+					   char *buf)
+{
+	return snprintf(buf, PAGE_SIZE, "%u\n", priv->ceiling);
+}
+
+static ssize_t stm32_lptim_cnt_set_ceiling(struct stm32_lptim_cnt *priv,
+					   const char *buf, size_t len)
+{
+	int ret;
+
+	if (stm32_lptim_is_enabled(priv))
+		return -EBUSY;
+
+	ret = kstrtouint(buf, 0, &priv->ceiling);
+	if (ret)
+		return ret;
+
+	if (priv->ceiling > STM32_LPTIM_MAX_ARR)
+		return -EINVAL;
+
+	return len;
+}
+
+static ssize_t stm32_lptim_cnt_get_preset_iio(struct iio_dev *indio_dev,
+					      uintptr_t private,
+					      const struct iio_chan_spec *chan,
+					      char *buf)
+{
+	struct stm32_lptim_cnt *priv = iio_priv(indio_dev);
+
+	return stm32_lptim_cnt_get_ceiling(priv, buf);
+}
+
+static ssize_t stm32_lptim_cnt_set_preset_iio(struct iio_dev *indio_dev,
+					      uintptr_t private,
+					      const struct iio_chan_spec *chan,
+					      const char *buf, size_t len)
+{
+	struct stm32_lptim_cnt *priv = iio_priv(indio_dev);
+
+	return stm32_lptim_cnt_set_ceiling(priv, buf, len);
+}
+
+/* LP timer with encoder */
+static const struct iio_chan_spec_ext_info stm32_lptim_enc_ext_info[] = {
+	{
+		.name = "preset",
+		.shared = IIO_SEPARATE,
+		.read = stm32_lptim_cnt_get_preset_iio,
+		.write = stm32_lptim_cnt_set_preset_iio,
+	},
+	IIO_ENUM("polarity", IIO_SEPARATE, &stm32_lptim_cnt_polarity_en),
+	IIO_ENUM_AVAILABLE("polarity", &stm32_lptim_cnt_polarity_en),
+	IIO_ENUM("quadrature_mode", IIO_SEPARATE,
+		 &stm32_lptim_quadrature_mode_en),
+	IIO_ENUM_AVAILABLE("quadrature_mode", &stm32_lptim_quadrature_mode_en),
+	{}
+};
+
+static const struct iio_chan_spec stm32_lptim_enc_channels = {
+	.type = IIO_COUNT,
+	.channel = 0,
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+			      BIT(IIO_CHAN_INFO_ENABLE) |
+			      BIT(IIO_CHAN_INFO_SCALE),
+	.ext_info = stm32_lptim_enc_ext_info,
+	.indexed = 1,
+};
+
+/* LP timer without encoder (counter only) */
+static const struct iio_chan_spec_ext_info stm32_lptim_cnt_ext_info[] = {
+	{
+		.name = "preset",
+		.shared = IIO_SEPARATE,
+		.read = stm32_lptim_cnt_get_preset_iio,
+		.write = stm32_lptim_cnt_set_preset_iio,
+	},
+	IIO_ENUM("polarity", IIO_SEPARATE, &stm32_lptim_cnt_polarity_en),
+	IIO_ENUM_AVAILABLE("polarity", &stm32_lptim_cnt_polarity_en),
+	{}
+};
+
+static const struct iio_chan_spec stm32_lptim_cnt_channels = {
+	.type = IIO_COUNT,
+	.channel = 0,
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+			      BIT(IIO_CHAN_INFO_ENABLE) |
+			      BIT(IIO_CHAN_INFO_SCALE),
+	.ext_info = stm32_lptim_cnt_ext_info,
+	.indexed = 1,
+};
+
+/**
+ * stm32_lptim_cnt_function - enumerates stm32 LPTimer counter & encoder modes
+ * @STM32_LPTIM_COUNTER_INCREASE: up count on IN1 rising, falling or both edges
+ * @STM32_LPTIM_ENCODER_BOTH_EDGE: count on both edges (IN1 & IN2 quadrature)
+ */
+enum stm32_lptim_cnt_function {
+	STM32_LPTIM_COUNTER_INCREASE,
+	STM32_LPTIM_ENCODER_BOTH_EDGE,
+};
+
+static enum counter_count_function stm32_lptim_cnt_functions[] = {
+	[STM32_LPTIM_COUNTER_INCREASE] = COUNTER_COUNT_FUNCTION_INCREASE,
+	[STM32_LPTIM_ENCODER_BOTH_EDGE] = COUNTER_COUNT_FUNCTION_QUADRATURE_X4,
+};
+
+enum stm32_lptim_synapse_action {
+	STM32_LPTIM_SYNAPSE_ACTION_RISING_EDGE,
+	STM32_LPTIM_SYNAPSE_ACTION_FALLING_EDGE,
+	STM32_LPTIM_SYNAPSE_ACTION_BOTH_EDGES,
+	STM32_LPTIM_SYNAPSE_ACTION_NONE,
+};
+
+static enum counter_synapse_action stm32_lptim_cnt_synapse_actions[] = {
+	/* Index must match with stm32_lptim_cnt_polarity[] (priv->polarity) */
+	[STM32_LPTIM_SYNAPSE_ACTION_RISING_EDGE] = COUNTER_SYNAPSE_ACTION_RISING_EDGE,
+	[STM32_LPTIM_SYNAPSE_ACTION_FALLING_EDGE] = COUNTER_SYNAPSE_ACTION_FALLING_EDGE,
+	[STM32_LPTIM_SYNAPSE_ACTION_BOTH_EDGES] = COUNTER_SYNAPSE_ACTION_BOTH_EDGES,
+	[STM32_LPTIM_SYNAPSE_ACTION_NONE] = COUNTER_SYNAPSE_ACTION_NONE,
+};
+
+static int stm32_lptim_cnt_read(struct counter_device *counter,
+				struct counter_count *count,
+				struct counter_count_read_value *val)
+{
+	struct stm32_lptim_cnt *const priv = counter->priv;
+	u32 cnt;
+	int ret;
+
+	ret = regmap_read(priv->regmap, STM32_LPTIM_CNT, &cnt);
+	if (ret)
+		return ret;
+
+	counter_count_read_value_set(val, COUNTER_COUNT_POSITION, &cnt);
+
+	return 0;
+}
+
+static int stm32_lptim_cnt_function_get(struct counter_device *counter,
+					struct counter_count *count,
+					size_t *function)
+{
+	struct stm32_lptim_cnt *const priv = counter->priv;
+
+	if (!priv->quadrature_mode) {
+		*function = STM32_LPTIM_COUNTER_INCREASE;
+		return 0;
+	}
+
+	if (priv->polarity == STM32_LPTIM_SYNAPSE_ACTION_BOTH_EDGES) {
+		*function = STM32_LPTIM_ENCODER_BOTH_EDGE;
+		return 0;
+	}
+
+	return -EINVAL;
+}
+
+static int stm32_lptim_cnt_function_set(struct counter_device *counter,
+					struct counter_count *count,
+					size_t function)
+{
+	struct stm32_lptim_cnt *const priv = counter->priv;
+
+	if (stm32_lptim_is_enabled(priv))
+		return -EBUSY;
+
+	switch (function) {
+	case STM32_LPTIM_COUNTER_INCREASE:
+		priv->quadrature_mode = 0;
+		return 0;
+	case STM32_LPTIM_ENCODER_BOTH_EDGE:
+		priv->quadrature_mode = 1;
+		priv->polarity = STM32_LPTIM_SYNAPSE_ACTION_BOTH_EDGES;
+		return 0;
+	}
+
+	return -EINVAL;
+}
+
+static ssize_t stm32_lptim_cnt_enable_read(struct counter_device *counter,
+					   struct counter_count *count,
+					   void *private, char *buf)
+{
+	struct stm32_lptim_cnt *const priv = counter->priv;
+	int ret;
+
+	ret = stm32_lptim_is_enabled(priv);
+	if (ret < 0)
+		return ret;
+
+	return scnprintf(buf, PAGE_SIZE, "%u\n", ret);
+}
+
+static ssize_t stm32_lptim_cnt_enable_write(struct counter_device *counter,
+					    struct counter_count *count,
+					    void *private,
+					    const char *buf, size_t len)
+{
+	struct stm32_lptim_cnt *const priv = counter->priv;
+	bool enable;
+	int ret;
+
+	ret = kstrtobool(buf, &enable);
+	if (ret)
+		return ret;
+
+	/* Check nobody uses the timer, or already disabled/enabled */
+	ret = stm32_lptim_is_enabled(priv);
+	if ((ret < 0) || (!ret && !enable))
+		return ret;
+	if (enable && ret)
+		return -EBUSY;
+
+	ret = stm32_lptim_setup(priv, enable);
+	if (ret)
+		return ret;
+
+	ret = stm32_lptim_set_enable_state(priv, enable);
+	if (ret)
+		return ret;
+
+	return len;
+}
+
+static ssize_t stm32_lptim_cnt_ceiling_read(struct counter_device *counter,
+					    struct counter_count *count,
+					    void *private, char *buf)
+{
+	struct stm32_lptim_cnt *const priv = counter->priv;
+
+	return stm32_lptim_cnt_get_ceiling(priv, buf);
+}
+
+static ssize_t stm32_lptim_cnt_ceiling_write(struct counter_device *counter,
+					     struct counter_count *count,
+					     void *private,
+					     const char *buf, size_t len)
+{
+	struct stm32_lptim_cnt *const priv = counter->priv;
+
+	return stm32_lptim_cnt_set_ceiling(priv, buf, len);
+}
+
+static const struct counter_count_ext stm32_lptim_cnt_ext[] = {
+	{
+		.name = "enable",
+		.read = stm32_lptim_cnt_enable_read,
+		.write = stm32_lptim_cnt_enable_write
+	},
+	{
+		.name = "ceiling",
+		.read = stm32_lptim_cnt_ceiling_read,
+		.write = stm32_lptim_cnt_ceiling_write
+	},
+};
+
+static int stm32_lptim_cnt_action_get(struct counter_device *counter,
+				      struct counter_count *count,
+				      struct counter_synapse *synapse,
+				      size_t *action)
+{
+	struct stm32_lptim_cnt *const priv = counter->priv;
+	size_t function;
+	int err;
+
+	err = stm32_lptim_cnt_function_get(counter, count, &function);
+	if (err)
+		return err;
+
+	switch (function) {
+	case STM32_LPTIM_COUNTER_INCREASE:
+		/* LP Timer acts as up-counter on input 1 */
+		if (synapse->signal->id == count->synapses[0].signal->id)
+			*action = priv->polarity;
+		else
+			*action = STM32_LPTIM_SYNAPSE_ACTION_NONE;
+		return 0;
+	case STM32_LPTIM_ENCODER_BOTH_EDGE:
+		*action = priv->polarity;
+		return 0;
+	}
+
+	return -EINVAL;
+}
+
+static int stm32_lptim_cnt_action_set(struct counter_device *counter,
+				      struct counter_count *count,
+				      struct counter_synapse *synapse,
+				      size_t action)
+{
+	struct stm32_lptim_cnt *const priv = counter->priv;
+	size_t function;
+	int err;
+
+	if (stm32_lptim_is_enabled(priv))
+		return -EBUSY;
+
+	err = stm32_lptim_cnt_function_get(counter, count, &function);
+	if (err)
+		return err;
+
+	/* only set polarity when in counter mode (on input 1) */
+	if (function == STM32_LPTIM_COUNTER_INCREASE
+	    && synapse->signal->id == count->synapses[0].signal->id) {
+		switch (action) {
+		case STM32_LPTIM_SYNAPSE_ACTION_RISING_EDGE:
+		case STM32_LPTIM_SYNAPSE_ACTION_FALLING_EDGE:
+		case STM32_LPTIM_SYNAPSE_ACTION_BOTH_EDGES:
+			priv->polarity = action;
+			return 0;
+		}
+	}
+
+	return -EINVAL;
+}
+
+static const struct counter_ops stm32_lptim_cnt_ops = {
+	.count_read = stm32_lptim_cnt_read,
+	.function_get = stm32_lptim_cnt_function_get,
+	.function_set = stm32_lptim_cnt_function_set,
+	.action_get = stm32_lptim_cnt_action_get,
+	.action_set = stm32_lptim_cnt_action_set,
+};
+
+static struct counter_signal stm32_lptim_cnt_signals[] = {
+	{
+		.id = 0,
+		.name = "Channel 1 Quadrature A"
+	},
+	{
+		.id = 1,
+		.name = "Channel 1 Quadrature B"
+	}
+};
+
+static struct counter_synapse stm32_lptim_cnt_synapses[] = {
+	{
+		.actions_list = stm32_lptim_cnt_synapse_actions,
+		.num_actions = ARRAY_SIZE(stm32_lptim_cnt_synapse_actions),
+		.signal = &stm32_lptim_cnt_signals[0]
+	},
+	{
+		.actions_list = stm32_lptim_cnt_synapse_actions,
+		.num_actions = ARRAY_SIZE(stm32_lptim_cnt_synapse_actions),
+		.signal = &stm32_lptim_cnt_signals[1]
+	}
+};
+
+/* LP timer with encoder */
+static struct counter_count stm32_lptim_enc_counts = {
+	.id = 0,
+	.name = "LPTimer Count",
+	.functions_list = stm32_lptim_cnt_functions,
+	.num_functions = ARRAY_SIZE(stm32_lptim_cnt_functions),
+	.synapses = stm32_lptim_cnt_synapses,
+	.num_synapses = ARRAY_SIZE(stm32_lptim_cnt_synapses),
+	.ext = stm32_lptim_cnt_ext,
+	.num_ext = ARRAY_SIZE(stm32_lptim_cnt_ext)
+};
+
+/* LP timer without encoder (counter only) */
+static struct counter_count stm32_lptim_in1_counts = {
+	.id = 0,
+	.name = "LPTimer Count",
+	.functions_list = stm32_lptim_cnt_functions,
+	.num_functions = 1,
+	.synapses = stm32_lptim_cnt_synapses,
+	.num_synapses = 1,
+	.ext = stm32_lptim_cnt_ext,
+	.num_ext = ARRAY_SIZE(stm32_lptim_cnt_ext)
+};
+
+static int stm32_lptim_cnt_probe(struct platform_device *pdev)
+{
+	struct stm32_lptimer *ddata = dev_get_drvdata(pdev->dev.parent);
+	struct stm32_lptim_cnt *priv;
+	struct iio_dev *indio_dev;
+	int ret;
+
+	if (IS_ERR_OR_NULL(ddata))
+		return -EINVAL;
+
+	indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*priv));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	priv = iio_priv(indio_dev);
+	priv->dev = &pdev->dev;
+	priv->regmap = ddata->regmap;
+	priv->clk = ddata->clk;
+	priv->ceiling = STM32_LPTIM_MAX_ARR;
+
+	/* Initialize IIO device */
+	indio_dev->name = dev_name(&pdev->dev);
+	indio_dev->dev.parent = &pdev->dev;
+	indio_dev->dev.of_node = pdev->dev.of_node;
+	indio_dev->info = &stm32_lptim_cnt_iio_info;
+	if (ddata->has_encoder)
+		indio_dev->channels = &stm32_lptim_enc_channels;
+	else
+		indio_dev->channels = &stm32_lptim_cnt_channels;
+	indio_dev->num_channels = 1;
+
+	/* Initialize Counter device */
+	priv->counter.name = dev_name(&pdev->dev);
+	priv->counter.parent = &pdev->dev;
+	priv->counter.ops = &stm32_lptim_cnt_ops;
+	if (ddata->has_encoder) {
+		priv->counter.counts = &stm32_lptim_enc_counts;
+		priv->counter.num_signals = ARRAY_SIZE(stm32_lptim_cnt_signals);
+	} else {
+		priv->counter.counts = &stm32_lptim_in1_counts;
+		priv->counter.num_signals = 1;
+	}
+	priv->counter.num_counts = 1;
+	priv->counter.signals = stm32_lptim_cnt_signals;
+	priv->counter.priv = priv;
+
+	platform_set_drvdata(pdev, priv);
+
+	ret = devm_iio_device_register(&pdev->dev, indio_dev);
+	if (ret)
+		return ret;
+
+	return devm_counter_register(&pdev->dev, &priv->counter);
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int stm32_lptim_cnt_suspend(struct device *dev)
+{
+	struct stm32_lptim_cnt *priv = dev_get_drvdata(dev);
+	int ret;
+
+	/* Only take care of enabled counter: don't disturb other MFD child */
+	if (priv->enabled) {
+		ret = stm32_lptim_setup(priv, 0);
+		if (ret)
+			return ret;
+
+		ret = stm32_lptim_set_enable_state(priv, 0);
+		if (ret)
+			return ret;
+
+		/* Force enable state for later resume */
+		priv->enabled = true;
+	}
+
+	return pinctrl_pm_select_sleep_state(dev);
+}
+
+static int stm32_lptim_cnt_resume(struct device *dev)
+{
+	struct stm32_lptim_cnt *priv = dev_get_drvdata(dev);
+	int ret;
+
+	ret = pinctrl_pm_select_default_state(dev);
+	if (ret)
+		return ret;
+
+	if (priv->enabled) {
+		priv->enabled = false;
+		ret = stm32_lptim_setup(priv, 1);
+		if (ret)
+			return ret;
+
+		ret = stm32_lptim_set_enable_state(priv, 1);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(stm32_lptim_cnt_pm_ops, stm32_lptim_cnt_suspend,
+			 stm32_lptim_cnt_resume);
+
+static const struct of_device_id stm32_lptim_cnt_of_match[] = {
+	{ .compatible = "st,stm32-lptimer-counter", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, stm32_lptim_cnt_of_match);
+
+static struct platform_driver stm32_lptim_cnt_driver = {
+	.probe = stm32_lptim_cnt_probe,
+	.driver = {
+		.name = "stm32-lptimer-counter",
+		.of_match_table = stm32_lptim_cnt_of_match,
+		.pm = &stm32_lptim_cnt_pm_ops,
+	},
+};
+module_platform_driver(stm32_lptim_cnt_driver);
+
+MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@st.com>");
+MODULE_ALIAS("platform:stm32-lptimer-counter");
+MODULE_DESCRIPTION("STMicroelectronics STM32 LPTIM counter driver");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/counter/stm32-timer-cnt.c b/drivers/counter/stm32-timer-cnt.c
new file mode 100644
index 0000000..644ba18
--- /dev/null
+++ b/drivers/counter/stm32-timer-cnt.c
@@ -0,0 +1,390 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * STM32 Timer Encoder and Counter driver
+ *
+ * Copyright (C) STMicroelectronics 2018
+ *
+ * Author: Benjamin Gaignard <benjamin.gaignard@st.com>
+ *
+ */
+#include <linux/counter.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/types.h>
+#include <linux/mfd/stm32-timers.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+#define TIM_CCMR_CCXS	(BIT(8) | BIT(0))
+#define TIM_CCMR_MASK	(TIM_CCMR_CC1S | TIM_CCMR_CC2S | \
+			 TIM_CCMR_IC1F | TIM_CCMR_IC2F)
+#define TIM_CCER_MASK	(TIM_CCER_CC1P | TIM_CCER_CC1NP | \
+			 TIM_CCER_CC2P | TIM_CCER_CC2NP)
+
+struct stm32_timer_cnt {
+	struct counter_device counter;
+	struct regmap *regmap;
+	struct clk *clk;
+	u32 ceiling;
+};
+
+/**
+ * stm32_count_function - enumerates stm32 timer counter encoder modes
+ * @STM32_COUNT_SLAVE_MODE_DISABLED: counts on internal clock when CEN=1
+ * @STM32_COUNT_ENCODER_MODE_1: counts TI1FP1 edges, depending on TI2FP2 level
+ * @STM32_COUNT_ENCODER_MODE_2: counts TI2FP2 edges, depending on TI1FP1 level
+ * @STM32_COUNT_ENCODER_MODE_3: counts on both TI1FP1 and TI2FP2 edges
+ */
+enum stm32_count_function {
+	STM32_COUNT_SLAVE_MODE_DISABLED = -1,
+	STM32_COUNT_ENCODER_MODE_1,
+	STM32_COUNT_ENCODER_MODE_2,
+	STM32_COUNT_ENCODER_MODE_3,
+};
+
+static enum counter_count_function stm32_count_functions[] = {
+	[STM32_COUNT_ENCODER_MODE_1] = COUNTER_COUNT_FUNCTION_QUADRATURE_X2_A,
+	[STM32_COUNT_ENCODER_MODE_2] = COUNTER_COUNT_FUNCTION_QUADRATURE_X2_B,
+	[STM32_COUNT_ENCODER_MODE_3] = COUNTER_COUNT_FUNCTION_QUADRATURE_X4,
+};
+
+static int stm32_count_read(struct counter_device *counter,
+			    struct counter_count *count,
+			    struct counter_count_read_value *val)
+{
+	struct stm32_timer_cnt *const priv = counter->priv;
+	u32 cnt;
+
+	regmap_read(priv->regmap, TIM_CNT, &cnt);
+	counter_count_read_value_set(val, COUNTER_COUNT_POSITION, &cnt);
+
+	return 0;
+}
+
+static int stm32_count_write(struct counter_device *counter,
+			     struct counter_count *count,
+			     struct counter_count_write_value *val)
+{
+	struct stm32_timer_cnt *const priv = counter->priv;
+	u32 cnt;
+	int err;
+
+	err = counter_count_write_value_get(&cnt, COUNTER_COUNT_POSITION, val);
+	if (err)
+		return err;
+
+	if (cnt > priv->ceiling)
+		return -EINVAL;
+
+	return regmap_write(priv->regmap, TIM_CNT, cnt);
+}
+
+static int stm32_count_function_get(struct counter_device *counter,
+				    struct counter_count *count,
+				    size_t *function)
+{
+	struct stm32_timer_cnt *const priv = counter->priv;
+	u32 smcr;
+
+	regmap_read(priv->regmap, TIM_SMCR, &smcr);
+
+	switch (smcr & TIM_SMCR_SMS) {
+	case 1:
+		*function = STM32_COUNT_ENCODER_MODE_1;
+		return 0;
+	case 2:
+		*function = STM32_COUNT_ENCODER_MODE_2;
+		return 0;
+	case 3:
+		*function = STM32_COUNT_ENCODER_MODE_3;
+		return 0;
+	}
+
+	return -EINVAL;
+}
+
+static int stm32_count_function_set(struct counter_device *counter,
+				    struct counter_count *count,
+				    size_t function)
+{
+	struct stm32_timer_cnt *const priv = counter->priv;
+	u32 cr1, sms;
+
+	switch (function) {
+	case STM32_COUNT_ENCODER_MODE_1:
+		sms = 1;
+		break;
+	case STM32_COUNT_ENCODER_MODE_2:
+		sms = 2;
+		break;
+	case STM32_COUNT_ENCODER_MODE_3:
+		sms = 3;
+		break;
+	default:
+		sms = 0;
+		break;
+	}
+
+	/* Store enable status */
+	regmap_read(priv->regmap, TIM_CR1, &cr1);
+
+	regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN, 0);
+
+	/* TIMx_ARR register shouldn't be buffered (ARPE=0) */
+	regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_ARPE, 0);
+	regmap_write(priv->regmap, TIM_ARR, priv->ceiling);
+
+	regmap_update_bits(priv->regmap, TIM_SMCR, TIM_SMCR_SMS, sms);
+
+	/* Make sure that registers are updated */
+	regmap_update_bits(priv->regmap, TIM_EGR, TIM_EGR_UG, TIM_EGR_UG);
+
+	/* Restore the enable status */
+	regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN, cr1);
+
+	return 0;
+}
+
+static ssize_t stm32_count_direction_read(struct counter_device *counter,
+				      struct counter_count *count,
+				      void *private, char *buf)
+{
+	struct stm32_timer_cnt *const priv = counter->priv;
+	const char *direction;
+	u32 cr1;
+
+	regmap_read(priv->regmap, TIM_CR1, &cr1);
+	direction = (cr1 & TIM_CR1_DIR) ? "backward" : "forward";
+
+	return scnprintf(buf, PAGE_SIZE, "%s\n", direction);
+}
+
+static ssize_t stm32_count_ceiling_read(struct counter_device *counter,
+					struct counter_count *count,
+					void *private, char *buf)
+{
+	struct stm32_timer_cnt *const priv = counter->priv;
+	u32 arr;
+
+	regmap_read(priv->regmap, TIM_ARR, &arr);
+
+	return snprintf(buf, PAGE_SIZE, "%u\n", arr);
+}
+
+static ssize_t stm32_count_ceiling_write(struct counter_device *counter,
+					 struct counter_count *count,
+					 void *private,
+					 const char *buf, size_t len)
+{
+	struct stm32_timer_cnt *const priv = counter->priv;
+	unsigned int ceiling;
+	int ret;
+
+	ret = kstrtouint(buf, 0, &ceiling);
+	if (ret)
+		return ret;
+
+	/* TIMx_ARR register shouldn't be buffered (ARPE=0) */
+	regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_ARPE, 0);
+	regmap_write(priv->regmap, TIM_ARR, ceiling);
+
+	priv->ceiling = ceiling;
+	return len;
+}
+
+static ssize_t stm32_count_enable_read(struct counter_device *counter,
+				       struct counter_count *count,
+				       void *private, char *buf)
+{
+	struct stm32_timer_cnt *const priv = counter->priv;
+	u32 cr1;
+
+	regmap_read(priv->regmap, TIM_CR1, &cr1);
+
+	return scnprintf(buf, PAGE_SIZE, "%d\n", (bool)(cr1 & TIM_CR1_CEN));
+}
+
+static ssize_t stm32_count_enable_write(struct counter_device *counter,
+					struct counter_count *count,
+					void *private,
+					const char *buf, size_t len)
+{
+	struct stm32_timer_cnt *const priv = counter->priv;
+	int err;
+	u32 cr1;
+	bool enable;
+
+	err = kstrtobool(buf, &enable);
+	if (err)
+		return err;
+
+	if (enable) {
+		regmap_read(priv->regmap, TIM_CR1, &cr1);
+			if (!(cr1 & TIM_CR1_CEN))
+				clk_enable(priv->clk);
+
+		regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN,
+				   TIM_CR1_CEN);
+	} else {
+		regmap_read(priv->regmap, TIM_CR1, &cr1);
+		regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN, 0);
+		if (cr1 & TIM_CR1_CEN)
+			clk_disable(priv->clk);
+	}
+
+	return len;
+}
+
+static const struct counter_count_ext stm32_count_ext[] = {
+	{
+		.name = "direction",
+		.read = stm32_count_direction_read,
+	},
+	{
+		.name = "enable",
+		.read = stm32_count_enable_read,
+		.write = stm32_count_enable_write
+	},
+	{
+		.name = "ceiling",
+		.read = stm32_count_ceiling_read,
+		.write = stm32_count_ceiling_write
+	},
+};
+
+enum stm32_synapse_action {
+	STM32_SYNAPSE_ACTION_NONE,
+	STM32_SYNAPSE_ACTION_BOTH_EDGES
+};
+
+static enum counter_synapse_action stm32_synapse_actions[] = {
+	[STM32_SYNAPSE_ACTION_NONE] = COUNTER_SYNAPSE_ACTION_NONE,
+	[STM32_SYNAPSE_ACTION_BOTH_EDGES] = COUNTER_SYNAPSE_ACTION_BOTH_EDGES
+};
+
+static int stm32_action_get(struct counter_device *counter,
+			    struct counter_count *count,
+			    struct counter_synapse *synapse,
+			    size_t *action)
+{
+	size_t function;
+	int err;
+
+	/* Default action mode (e.g. STM32_COUNT_SLAVE_MODE_DISABLED) */
+	*action = STM32_SYNAPSE_ACTION_NONE;
+
+	err = stm32_count_function_get(counter, count, &function);
+	if (err)
+		return 0;
+
+	switch (function) {
+	case STM32_COUNT_ENCODER_MODE_1:
+		/* counts up/down on TI1FP1 edge depending on TI2FP2 level */
+		if (synapse->signal->id == count->synapses[0].signal->id)
+			*action = STM32_SYNAPSE_ACTION_BOTH_EDGES;
+		break;
+	case STM32_COUNT_ENCODER_MODE_2:
+		/* counts up/down on TI2FP2 edge depending on TI1FP1 level */
+		if (synapse->signal->id == count->synapses[1].signal->id)
+			*action = STM32_SYNAPSE_ACTION_BOTH_EDGES;
+		break;
+	case STM32_COUNT_ENCODER_MODE_3:
+		/* counts up/down on both TI1FP1 and TI2FP2 edges */
+		*action = STM32_SYNAPSE_ACTION_BOTH_EDGES;
+		break;
+	}
+
+	return 0;
+}
+
+static const struct counter_ops stm32_timer_cnt_ops = {
+	.count_read = stm32_count_read,
+	.count_write = stm32_count_write,
+	.function_get = stm32_count_function_get,
+	.function_set = stm32_count_function_set,
+	.action_get = stm32_action_get,
+};
+
+static struct counter_signal stm32_signals[] = {
+	{
+		.id = 0,
+		.name = "Channel 1 Quadrature A"
+	},
+	{
+		.id = 1,
+		.name = "Channel 1 Quadrature B"
+	}
+};
+
+static struct counter_synapse stm32_count_synapses[] = {
+	{
+		.actions_list = stm32_synapse_actions,
+		.num_actions = ARRAY_SIZE(stm32_synapse_actions),
+		.signal = &stm32_signals[0]
+	},
+	{
+		.actions_list = stm32_synapse_actions,
+		.num_actions = ARRAY_SIZE(stm32_synapse_actions),
+		.signal = &stm32_signals[1]
+	}
+};
+
+static struct counter_count stm32_counts = {
+	.id = 0,
+	.name = "Channel 1 Count",
+	.functions_list = stm32_count_functions,
+	.num_functions = ARRAY_SIZE(stm32_count_functions),
+	.synapses = stm32_count_synapses,
+	.num_synapses = ARRAY_SIZE(stm32_count_synapses),
+	.ext = stm32_count_ext,
+	.num_ext = ARRAY_SIZE(stm32_count_ext)
+};
+
+static int stm32_timer_cnt_probe(struct platform_device *pdev)
+{
+	struct stm32_timers *ddata = dev_get_drvdata(pdev->dev.parent);
+	struct device *dev = &pdev->dev;
+	struct stm32_timer_cnt *priv;
+
+	if (IS_ERR_OR_NULL(ddata))
+		return -EINVAL;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->regmap = ddata->regmap;
+	priv->clk = ddata->clk;
+	priv->ceiling = ddata->max_arr;
+
+	priv->counter.name = dev_name(dev);
+	priv->counter.parent = dev;
+	priv->counter.ops = &stm32_timer_cnt_ops;
+	priv->counter.counts = &stm32_counts;
+	priv->counter.num_counts = 1;
+	priv->counter.signals = stm32_signals;
+	priv->counter.num_signals = ARRAY_SIZE(stm32_signals);
+	priv->counter.priv = priv;
+
+	/* Register Counter device */
+	return devm_counter_register(dev, &priv->counter);
+}
+
+static const struct of_device_id stm32_timer_cnt_of_match[] = {
+	{ .compatible = "st,stm32-timer-counter", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, stm32_timer_cnt_of_match);
+
+static struct platform_driver stm32_timer_cnt_driver = {
+	.probe = stm32_timer_cnt_probe,
+	.driver = {
+		.name = "stm32-timer-counter",
+		.of_match_table = stm32_timer_cnt_of_match,
+	},
+};
+module_platform_driver(stm32_timer_cnt_driver);
+
+MODULE_AUTHOR("Benjamin Gaignard <benjamin.gaignard@st.com>");
+MODULE_ALIAS("platform:stm32-timer-counter");
+MODULE_DESCRIPTION("STMicroelectronics STM32 TIMER counter driver");
+MODULE_LICENSE("GPL v2");