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");