v4.19.13 snapshot.
diff --git a/drivers/iio/adc/lp8788_adc.c b/drivers/iio/adc/lp8788_adc.c
new file mode 100644
index 0000000..3bc4df9
--- /dev/null
+++ b/drivers/iio/adc/lp8788_adc.c
@@ -0,0 +1,253 @@
+/*
+ * TI LP8788 MFD - ADC driver
+ *
+ * Copyright 2012 Texas Instruments
+ *
+ * Author: Milo(Woogyom) Kim <milo.kim@ti.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/delay.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/driver.h>
+#include <linux/iio/machine.h>
+#include <linux/mfd/lp8788.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+/* register address */
+#define LP8788_ADC_CONF			0x60
+#define LP8788_ADC_RAW			0x61
+#define LP8788_ADC_DONE			0x63
+
+#define ADC_CONV_START			1
+
+struct lp8788_adc {
+	struct lp8788 *lp;
+	struct iio_map *map;
+	struct mutex lock;
+};
+
+static const int lp8788_scale[LPADC_MAX] = {
+	[LPADC_VBATT_5P5] = 1343101,
+	[LPADC_VIN_CHG]   = 3052503,
+	[LPADC_IBATT]     = 610500,
+	[LPADC_IC_TEMP]   = 61050,
+	[LPADC_VBATT_6P0] = 1465201,
+	[LPADC_VBATT_5P0] = 1221001,
+	[LPADC_ADC1]      = 610500,
+	[LPADC_ADC2]      = 610500,
+	[LPADC_VDD]       = 1025641,
+	[LPADC_VCOIN]     = 757020,
+	[LPADC_ADC3]      = 610500,
+	[LPADC_ADC4]      = 610500,
+};
+
+static int lp8788_get_adc_result(struct lp8788_adc *adc, enum lp8788_adc_id id,
+				int *val)
+{
+	unsigned int msb;
+	unsigned int lsb;
+	unsigned int result;
+	u8 data;
+	u8 rawdata[2];
+	int size = ARRAY_SIZE(rawdata);
+	int retry = 5;
+	int ret;
+
+	data = (id << 1) | ADC_CONV_START;
+	ret = lp8788_write_byte(adc->lp, LP8788_ADC_CONF, data);
+	if (ret)
+		goto err_io;
+
+	/* retry until adc conversion is done */
+	data = 0;
+	while (retry--) {
+		usleep_range(100, 200);
+
+		ret = lp8788_read_byte(adc->lp, LP8788_ADC_DONE, &data);
+		if (ret)
+			goto err_io;
+
+		/* conversion done */
+		if (data)
+			break;
+	}
+
+	ret = lp8788_read_multi_bytes(adc->lp, LP8788_ADC_RAW, rawdata, size);
+	if (ret)
+		goto err_io;
+
+	msb = (rawdata[0] << 4) & 0x00000ff0;
+	lsb = (rawdata[1] >> 4) & 0x0000000f;
+	result = msb | lsb;
+	*val = result;
+
+	return 0;
+
+err_io:
+	return ret;
+}
+
+static int lp8788_adc_read_raw(struct iio_dev *indio_dev,
+			struct iio_chan_spec const *chan,
+			int *val, int *val2, long mask)
+{
+	struct lp8788_adc *adc = iio_priv(indio_dev);
+	enum lp8788_adc_id id = chan->channel;
+	int ret;
+
+	mutex_lock(&adc->lock);
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		ret = lp8788_get_adc_result(adc, id, val) ? -EIO : IIO_VAL_INT;
+		break;
+	case IIO_CHAN_INFO_SCALE:
+		*val = lp8788_scale[id] / 1000000;
+		*val2 = lp8788_scale[id] % 1000000;
+		ret = IIO_VAL_INT_PLUS_MICRO;
+		break;
+	default:
+		ret = -EINVAL;
+		break;
+	}
+
+	mutex_unlock(&adc->lock);
+
+	return ret;
+}
+
+static const struct iio_info lp8788_adc_info = {
+	.read_raw = &lp8788_adc_read_raw,
+};
+
+#define LP8788_CHAN(_id, _type) {				\
+		.type = _type,					\
+		.indexed = 1,					\
+		.channel = LPADC_##_id,				\
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |	\
+			BIT(IIO_CHAN_INFO_SCALE),		\
+		.datasheet_name = #_id,				\
+}
+
+static const struct iio_chan_spec lp8788_adc_channels[] = {
+	[LPADC_VBATT_5P5] = LP8788_CHAN(VBATT_5P5, IIO_VOLTAGE),
+	[LPADC_VIN_CHG]   = LP8788_CHAN(VIN_CHG, IIO_VOLTAGE),
+	[LPADC_IBATT]     = LP8788_CHAN(IBATT, IIO_CURRENT),
+	[LPADC_IC_TEMP]   = LP8788_CHAN(IC_TEMP, IIO_TEMP),
+	[LPADC_VBATT_6P0] = LP8788_CHAN(VBATT_6P0, IIO_VOLTAGE),
+	[LPADC_VBATT_5P0] = LP8788_CHAN(VBATT_5P0, IIO_VOLTAGE),
+	[LPADC_ADC1]      = LP8788_CHAN(ADC1, IIO_VOLTAGE),
+	[LPADC_ADC2]      = LP8788_CHAN(ADC2, IIO_VOLTAGE),
+	[LPADC_VDD]       = LP8788_CHAN(VDD, IIO_VOLTAGE),
+	[LPADC_VCOIN]     = LP8788_CHAN(VCOIN, IIO_VOLTAGE),
+	[LPADC_ADC3]      = LP8788_CHAN(ADC3, IIO_VOLTAGE),
+	[LPADC_ADC4]      = LP8788_CHAN(ADC4, IIO_VOLTAGE),
+};
+
+/* default maps used by iio consumer (lp8788-charger driver) */
+static struct iio_map lp8788_default_iio_maps[] = {
+	{
+		.consumer_dev_name = "lp8788-charger",
+		.consumer_channel = "lp8788_vbatt_5p0",
+		.adc_channel_label = "VBATT_5P0",
+	},
+	{
+		.consumer_dev_name = "lp8788-charger",
+		.consumer_channel = "lp8788_adc1",
+		.adc_channel_label = "ADC1",
+	},
+	{ }
+};
+
+static int lp8788_iio_map_register(struct iio_dev *indio_dev,
+				struct lp8788_platform_data *pdata,
+				struct lp8788_adc *adc)
+{
+	struct iio_map *map;
+	int ret;
+
+	map = (!pdata || !pdata->adc_pdata) ?
+		lp8788_default_iio_maps : pdata->adc_pdata;
+
+	ret = iio_map_array_register(indio_dev, map);
+	if (ret) {
+		dev_err(&indio_dev->dev, "iio map err: %d\n", ret);
+		return ret;
+	}
+
+	adc->map = map;
+	return 0;
+}
+
+static int lp8788_adc_probe(struct platform_device *pdev)
+{
+	struct lp8788 *lp = dev_get_drvdata(pdev->dev.parent);
+	struct iio_dev *indio_dev;
+	struct lp8788_adc *adc;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*adc));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	adc = iio_priv(indio_dev);
+	adc->lp = lp;
+	platform_set_drvdata(pdev, indio_dev);
+
+	indio_dev->dev.of_node = pdev->dev.of_node;
+	ret = lp8788_iio_map_register(indio_dev, lp->pdata, adc);
+	if (ret)
+		return ret;
+
+	mutex_init(&adc->lock);
+
+	indio_dev->dev.parent = &pdev->dev;
+	indio_dev->name = pdev->name;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->info = &lp8788_adc_info;
+	indio_dev->channels = lp8788_adc_channels;
+	indio_dev->num_channels = ARRAY_SIZE(lp8788_adc_channels);
+
+	ret = iio_device_register(indio_dev);
+	if (ret) {
+		dev_err(&pdev->dev, "iio dev register err: %d\n", ret);
+		goto err_iio_device;
+	}
+
+	return 0;
+
+err_iio_device:
+	iio_map_array_unregister(indio_dev);
+	return ret;
+}
+
+static int lp8788_adc_remove(struct platform_device *pdev)
+{
+	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
+
+	iio_device_unregister(indio_dev);
+	iio_map_array_unregister(indio_dev);
+
+	return 0;
+}
+
+static struct platform_driver lp8788_adc_driver = {
+	.probe = lp8788_adc_probe,
+	.remove = lp8788_adc_remove,
+	.driver = {
+		.name = LP8788_DEV_ADC,
+	},
+};
+module_platform_driver(lp8788_adc_driver);
+
+MODULE_DESCRIPTION("Texas Instruments LP8788 ADC Driver");
+MODULE_AUTHOR("Milo Kim");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:lp8788-adc");