iio: cdc: ad7746: Move driver out of staging.

All known major issues with this driver resolved so time to move
it out of staging. This also allows us to remove the now empty
staging/iio/cdc directory and build files.

Note this cleanup work was done using the roadtest framework.
https://lore.kernel.org/all/20220311162445.346685-1-vincent.whitchurch@axis.com/

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>

3 files changed, 831 insertions, 0 deletions

diff --git a/drivers/iio/cdc/Kconfig b/drivers/iio/cdc/Kconfig
index 5e3319a3ff48..e0a5ce66a984 100644
--- a/drivers/iio/cdc/Kconfig
+++ b/drivers/iio/cdc/Kconfig
@@ -14,4 +14,14 @@ config AD7150
 	  To compile this driver as a module, choose M here: the
 	  module will be called ad7150.
 
+config AD7746
+	tristate "Analog Devices AD7745, AD7746 AD7747 capacitive sensor driver"
+	depends on I2C
+	help
+	  Say yes here to build support for Analog Devices capacitive sensors.
+	  (AD7745, AD7746, AD7747) Provides direct access via sysfs.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called ad7746.
+
 endmenu
diff --git a/drivers/iio/cdc/Makefile b/drivers/iio/cdc/Makefile
index ee490637b032..41db756d8020 100644
--- a/drivers/iio/cdc/Makefile
+++ b/drivers/iio/cdc/Makefile
@@ -4,3 +4,4 @@
 #
 
 obj-$(CONFIG_AD7150) += ad7150.o
+obj-$(CONFIG_AD7746) += ad7746.o
diff --git a/drivers/iio/cdc/ad7746.c b/drivers/iio/cdc/ad7746.c
new file mode 100644
index 000000000000..b266f5328140
--- /dev/null
+++ b/drivers/iio/cdc/ad7746.c
@@ -0,0 +1,820 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * AD7746 capacitive sensor driver supporting AD7745, AD7746 and AD7747
+ *
+ * Copyright 2011 Analog Devices Inc.
+ */
+
+#include <linux/bitfield.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/stat.h>
+#include <linux/sysfs.h>
+
+#include <asm/unaligned.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+
+/* AD7746 Register Definition */
+
+#define AD7746_REG_STATUS		0
+#define AD7746_REG_CAP_DATA_HIGH	1
+#define AD7746_REG_VT_DATA_HIGH		4
+#define AD7746_REG_CAP_SETUP		7
+#define AD7746_REG_VT_SETUP		8
+#define AD7746_REG_EXC_SETUP		9
+#define AD7746_REG_CFG			10
+#define AD7746_REG_CAPDACA		11
+#define AD7746_REG_CAPDACB		12
+#define AD7746_REG_CAP_OFFH		13
+#define AD7746_REG_CAP_GAINH		15
+#define AD7746_REG_VOLT_GAINH		17
+
+/* Status Register Bit Designations (AD7746_REG_STATUS) */
+#define AD7746_STATUS_EXCERR		BIT(3)
+#define AD7746_STATUS_RDY		BIT(2)
+#define AD7746_STATUS_RDYVT		BIT(1)
+#define AD7746_STATUS_RDYCAP		BIT(0)
+
+/* Capacitive Channel Setup Register Bit Designations (AD7746_REG_CAP_SETUP) */
+#define AD7746_CAPSETUP_CAPEN		BIT(7)
+#define AD7746_CAPSETUP_CIN2		BIT(6) /* AD7746 only */
+#define AD7746_CAPSETUP_CAPDIFF		BIT(5)
+#define AD7746_CAPSETUP_CACHOP		BIT(0)
+
+/* Voltage/Temperature Setup Register Bit Designations (AD7746_REG_VT_SETUP) */
+#define AD7746_VTSETUP_VTEN		BIT(7)
+#define AD7746_VTSETUP_VTMD_MASK	GENMASK(6, 5)
+#define AD7746_VTSETUP_VTMD_INT_TEMP	0
+#define AD7746_VTSETUP_VTMD_EXT_TEMP	1
+#define AD7746_VTSETUP_VTMD_VDD_MON	2
+#define AD7746_VTSETUP_VTMD_EXT_VIN	3
+#define AD7746_VTSETUP_EXTREF		BIT(4)
+#define AD7746_VTSETUP_VTSHORT		BIT(1)
+#define AD7746_VTSETUP_VTCHOP		BIT(0)
+
+/* Excitation Setup Register Bit Designations (AD7746_REG_EXC_SETUP) */
+#define AD7746_EXCSETUP_CLKCTRL		BIT(7)
+#define AD7746_EXCSETUP_EXCON		BIT(6)
+#define AD7746_EXCSETUP_EXCB		BIT(5)
+#define AD7746_EXCSETUP_NEXCB		BIT(4)
+#define AD7746_EXCSETUP_EXCA		BIT(3)
+#define AD7746_EXCSETUP_NEXCA		BIT(2)
+#define AD7746_EXCSETUP_EXCLVL_MASK	GENMASK(1, 0)
+
+/* Config Register Bit Designations (AD7746_REG_CFG) */
+#define AD7746_CONF_VTFS_MASK		GENMASK(7, 6)
+#define AD7746_CONF_CAPFS_MASK		GENMASK(5, 3)
+#define AD7746_CONF_MODE_MASK		GENMASK(2, 0)
+#define AD7746_CONF_MODE_IDLE		0
+#define AD7746_CONF_MODE_CONT_CONV	1
+#define AD7746_CONF_MODE_SINGLE_CONV	2
+#define AD7746_CONF_MODE_PWRDN		3
+#define AD7746_CONF_MODE_OFFS_CAL	5
+#define AD7746_CONF_MODE_GAIN_CAL	6
+
+/* CAPDAC Register Bit Designations (AD7746_REG_CAPDACx) */
+#define AD7746_CAPDAC_DACEN		BIT(7)
+#define AD7746_CAPDAC_DACP_MASK		GENMASK(6, 0)
+
+struct ad7746_chip_info {
+	struct i2c_client *client;
+	struct mutex lock; /* protect sensor state */
+	/*
+	 * Capacitive channel digital filter setup;
+	 * conversion time/update rate setup per channel
+	 */
+	u8	config;
+	u8	cap_setup;
+	u8	vt_setup;
+	u8	capdac[2][2];
+	s8	capdac_set;
+};
+
+enum ad7746_chan {
+	VIN,
+	VIN_VDD,
+	TEMP_INT,
+	TEMP_EXT,
+	CIN1,
+	CIN1_DIFF,
+	CIN2,
+	CIN2_DIFF,
+};
+
+struct ad7746_chan_info {
+	u8 addr;
+	union {
+		u8 vtmd;
+		struct { /* CAP SETUP fields */
+			unsigned int cin2 : 1;
+			unsigned int capdiff : 1;
+		};
+	};
+};
+
+static const struct ad7746_chan_info ad7746_chan_info[] = {
+	[VIN] = {
+		.addr = AD7746_REG_VT_DATA_HIGH,
+		.vtmd = AD7746_VTSETUP_VTMD_EXT_VIN,
+	},
+	[VIN_VDD] = {
+		.addr = AD7746_REG_VT_DATA_HIGH,
+		.vtmd = AD7746_VTSETUP_VTMD_VDD_MON,
+	},
+	[TEMP_INT] = {
+		.addr = AD7746_REG_VT_DATA_HIGH,
+		.vtmd = AD7746_VTSETUP_VTMD_INT_TEMP,
+	},
+	[TEMP_EXT] = {
+		.addr = AD7746_REG_VT_DATA_HIGH,
+		.vtmd = AD7746_VTSETUP_VTMD_EXT_TEMP,
+	},
+	[CIN1] = {
+		.addr = AD7746_REG_CAP_DATA_HIGH,
+	},
+	[CIN1_DIFF] = {
+		.addr =  AD7746_REG_CAP_DATA_HIGH,
+		.capdiff = 1,
+	},
+	[CIN2] = {
+		.addr = AD7746_REG_CAP_DATA_HIGH,
+		.cin2 = 1,
+	},
+	[CIN2_DIFF] = {
+		.addr = AD7746_REG_CAP_DATA_HIGH,
+		.cin2 = 1,
+		.capdiff = 1,
+	},
+};
+
+static const struct iio_chan_spec ad7746_channels[] = {
+	[VIN] = {
+		.type = IIO_VOLTAGE,
+		.indexed = 1,
+		.channel = 0,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
+		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ),
+		.info_mask_shared_by_type_available = BIT(IIO_CHAN_INFO_SAMP_FREQ),
+		.address = VIN,
+	},
+	[VIN_VDD] = {
+		.type = IIO_VOLTAGE,
+		.indexed = 1,
+		.channel = 1,
+		.extend_name = "supply",
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
+		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ),
+		.info_mask_shared_by_type_available = BIT(IIO_CHAN_INFO_SAMP_FREQ),
+		.address = VIN_VDD,
+	},
+	[TEMP_INT] = {
+		.type = IIO_TEMP,
+		.indexed = 1,
+		.channel = 0,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
+		.address = TEMP_INT,
+	},
+	[TEMP_EXT] = {
+		.type = IIO_TEMP,
+		.indexed = 1,
+		.channel = 1,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
+		.address = TEMP_EXT,
+	},
+	[CIN1] = {
+		.type = IIO_CAPACITANCE,
+		.indexed = 1,
+		.channel = 0,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+		BIT(IIO_CHAN_INFO_CALIBSCALE) | BIT(IIO_CHAN_INFO_OFFSET),
+		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_CALIBBIAS) |
+		BIT(IIO_CHAN_INFO_SCALE) | BIT(IIO_CHAN_INFO_SAMP_FREQ),
+		.info_mask_shared_by_type_available = BIT(IIO_CHAN_INFO_SAMP_FREQ),
+		.address = CIN1,
+	},
+	[CIN1_DIFF] = {
+		.type = IIO_CAPACITANCE,
+		.differential = 1,
+		.indexed = 1,
+		.channel = 0,
+		.channel2 = 2,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+		BIT(IIO_CHAN_INFO_CALIBSCALE) | BIT(IIO_CHAN_INFO_ZEROPOINT),
+		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_CALIBBIAS) |
+		BIT(IIO_CHAN_INFO_SCALE) | BIT(IIO_CHAN_INFO_SAMP_FREQ),
+		.info_mask_shared_by_type_available = BIT(IIO_CHAN_INFO_SAMP_FREQ),
+		.address = CIN1_DIFF,
+	},
+	[CIN2] = {
+		.type = IIO_CAPACITANCE,
+		.indexed = 1,
+		.channel = 1,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+		BIT(IIO_CHAN_INFO_CALIBSCALE) | BIT(IIO_CHAN_INFO_OFFSET),
+		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_CALIBBIAS) |
+		BIT(IIO_CHAN_INFO_SCALE) | BIT(IIO_CHAN_INFO_SAMP_FREQ),
+		.info_mask_shared_by_type_available = BIT(IIO_CHAN_INFO_SAMP_FREQ),
+		.address = CIN2,
+	},
+	[CIN2_DIFF] = {
+		.type = IIO_CAPACITANCE,
+		.differential = 1,
+		.indexed = 1,
+		.channel = 1,
+		.channel2 = 3,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+		BIT(IIO_CHAN_INFO_CALIBSCALE) | BIT(IIO_CHAN_INFO_ZEROPOINT),
+		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_CALIBBIAS) |
+		BIT(IIO_CHAN_INFO_SCALE) | BIT(IIO_CHAN_INFO_SAMP_FREQ),
+		.info_mask_shared_by_type_available = BIT(IIO_CHAN_INFO_SAMP_FREQ),
+		.address = CIN2_DIFF,
+	}
+};
+
+/* Values are Update Rate (Hz), Conversion Time (ms) + 1*/
+static const unsigned char ad7746_vt_filter_rate_table[][2] = {
+	{ 50, 20 + 1 }, { 31, 32 + 1 }, { 16, 62 + 1 }, { 8, 122 + 1 },
+};
+
+static const unsigned char ad7746_cap_filter_rate_table[][2] = {
+	{ 91, 11 + 1 }, { 84, 12 + 1 }, { 50, 20 + 1 }, { 26, 38 + 1 },
+	{ 16, 62 + 1 }, { 13, 77 + 1 }, { 11, 92 + 1 }, { 9, 110 + 1 },
+};
+
+static int ad7746_set_capdac(struct ad7746_chip_info *chip, int channel)
+{
+	int ret = i2c_smbus_write_byte_data(chip->client,
+					    AD7746_REG_CAPDACA,
+					    chip->capdac[channel][0]);
+	if (ret < 0)
+		return ret;
+
+	return i2c_smbus_write_byte_data(chip->client,
+					  AD7746_REG_CAPDACB,
+					  chip->capdac[channel][1]);
+}
+
+static int ad7746_select_channel(struct iio_dev *indio_dev,
+				 struct iio_chan_spec const *chan)
+{
+	struct ad7746_chip_info *chip = iio_priv(indio_dev);
+	u8 vt_setup, cap_setup;
+	int ret, delay, idx;
+
+	switch (chan->type) {
+	case IIO_CAPACITANCE:
+		cap_setup = FIELD_PREP(AD7746_CAPSETUP_CIN2,
+				       ad7746_chan_info[chan->address].cin2) |
+			FIELD_PREP(AD7746_CAPSETUP_CAPDIFF,
+				   ad7746_chan_info[chan->address].capdiff) |
+			FIELD_PREP(AD7746_CAPSETUP_CAPEN, 1);
+		vt_setup = chip->vt_setup & ~AD7746_VTSETUP_VTEN;
+		idx = FIELD_GET(AD7746_CONF_CAPFS_MASK, chip->config);
+		delay = ad7746_cap_filter_rate_table[idx][1];
+
+		ret = ad7746_set_capdac(chip, chan->channel);
+		if (ret < 0)
+			return ret;
+
+		if (chip->capdac_set != chan->channel)
+			chip->capdac_set = chan->channel;
+		break;
+	case IIO_VOLTAGE:
+	case IIO_TEMP:
+		vt_setup = FIELD_PREP(AD7746_VTSETUP_VTMD_MASK,
+				      ad7746_chan_info[chan->address].vtmd) |
+			FIELD_PREP(AD7746_VTSETUP_VTEN, 1);
+		cap_setup = chip->cap_setup & ~AD7746_CAPSETUP_CAPEN;
+		idx = FIELD_GET(AD7746_CONF_VTFS_MASK, chip->config);
+		delay = ad7746_cap_filter_rate_table[idx][1];
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	if (chip->cap_setup != cap_setup) {
+		ret = i2c_smbus_write_byte_data(chip->client,
+						AD7746_REG_CAP_SETUP,
+						cap_setup);
+		if (ret < 0)
+			return ret;
+
+		chip->cap_setup = cap_setup;
+	}
+
+	if (chip->vt_setup != vt_setup) {
+		ret = i2c_smbus_write_byte_data(chip->client,
+						AD7746_REG_VT_SETUP,
+						vt_setup);
+		if (ret < 0)
+			return ret;
+
+		chip->vt_setup = vt_setup;
+	}
+
+	return delay;
+}
+
+static inline ssize_t ad7746_start_calib(struct device *dev,
+					 struct device_attribute *attr,
+					 const char *buf,
+					 size_t len,
+					 u8 regval)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct ad7746_chip_info *chip = iio_priv(indio_dev);
+	int ret, timeout = 10;
+	bool doit;
+
+	ret = kstrtobool(buf, &doit);
+	if (ret < 0)
+		return ret;
+
+	if (!doit)
+		return 0;
+
+	mutex_lock(&chip->lock);
+	regval |= chip->config;
+	ret = i2c_smbus_write_byte_data(chip->client, AD7746_REG_CFG, regval);
+	if (ret < 0)
+		goto unlock;
+
+	do {
+		msleep(20);
+		ret = i2c_smbus_read_byte_data(chip->client, AD7746_REG_CFG);
+		if (ret < 0)
+			goto unlock;
+
+	} while ((ret == regval) && timeout--);
+
+	mutex_unlock(&chip->lock);
+
+	return len;
+
+unlock:
+	mutex_unlock(&chip->lock);
+	return ret;
+}
+
+static ssize_t ad7746_start_offset_calib(struct device *dev,
+					 struct device_attribute *attr,
+					 const char *buf,
+					 size_t len)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	int ret = ad7746_select_channel(indio_dev,
+			      &ad7746_channels[to_iio_dev_attr(attr)->address]);
+	if (ret < 0)
+		return ret;
+
+	return ad7746_start_calib(dev, attr, buf, len,
+				  FIELD_PREP(AD7746_CONF_MODE_MASK,
+					     AD7746_CONF_MODE_OFFS_CAL));
+}
+
+static ssize_t ad7746_start_gain_calib(struct device *dev,
+				       struct device_attribute *attr,
+				       const char *buf,
+				       size_t len)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	int ret = ad7746_select_channel(indio_dev,
+			      &ad7746_channels[to_iio_dev_attr(attr)->address]);
+	if (ret < 0)
+		return ret;
+
+	return ad7746_start_calib(dev, attr, buf, len,
+				  FIELD_PREP(AD7746_CONF_MODE_MASK,
+					     AD7746_CONF_MODE_GAIN_CAL));
+}
+
+static IIO_DEVICE_ATTR(in_capacitance0_calibbias_calibration,
+		       0200, NULL, ad7746_start_offset_calib, CIN1);
+static IIO_DEVICE_ATTR(in_capacitance1_calibbias_calibration,
+		       0200, NULL, ad7746_start_offset_calib, CIN2);
+static IIO_DEVICE_ATTR(in_capacitance0_calibscale_calibration,
+		       0200, NULL, ad7746_start_gain_calib, CIN1);
+static IIO_DEVICE_ATTR(in_capacitance1_calibscale_calibration,
+		       0200, NULL, ad7746_start_gain_calib, CIN2);
+static IIO_DEVICE_ATTR(in_voltage0_calibscale_calibration,
+		       0200, NULL, ad7746_start_gain_calib, VIN);
+
+static int ad7746_store_cap_filter_rate_setup(struct ad7746_chip_info *chip,
+					      int val)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(ad7746_cap_filter_rate_table); i++)
+		if (val >= ad7746_cap_filter_rate_table[i][0])
+			break;
+
+	if (i >= ARRAY_SIZE(ad7746_cap_filter_rate_table))
+		i = ARRAY_SIZE(ad7746_cap_filter_rate_table) - 1;
+
+	chip->config &= ~AD7746_CONF_CAPFS_MASK;
+	chip->config |= FIELD_PREP(AD7746_CONF_CAPFS_MASK, i);
+
+	return 0;
+}
+
+static int ad7746_store_vt_filter_rate_setup(struct ad7746_chip_info *chip,
+					     int val)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(ad7746_vt_filter_rate_table); i++)
+		if (val >= ad7746_vt_filter_rate_table[i][0])
+			break;
+
+	if (i >= ARRAY_SIZE(ad7746_vt_filter_rate_table))
+		i = ARRAY_SIZE(ad7746_vt_filter_rate_table) - 1;
+
+	chip->config &= ~AD7746_CONF_VTFS_MASK;
+	chip->config |= FIELD_PREP(AD7746_CONF_VTFS_MASK, i);
+
+	return 0;
+}
+
+static struct attribute *ad7746_attributes[] = {
+	&iio_dev_attr_in_capacitance0_calibbias_calibration.dev_attr.attr,
+	&iio_dev_attr_in_capacitance0_calibscale_calibration.dev_attr.attr,
+	&iio_dev_attr_in_capacitance1_calibscale_calibration.dev_attr.attr,
+	&iio_dev_attr_in_capacitance1_calibbias_calibration.dev_attr.attr,
+	&iio_dev_attr_in_voltage0_calibscale_calibration.dev_attr.attr,
+	NULL,
+};
+
+static const struct attribute_group ad7746_attribute_group = {
+	.attrs = ad7746_attributes,
+};
+
+static int ad7746_write_raw(struct iio_dev *indio_dev,
+			    struct iio_chan_spec const *chan,
+			    int val,
+			    int val2,
+			    long mask)
+{
+	struct ad7746_chip_info *chip = iio_priv(indio_dev);
+	int ret, reg;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_CALIBSCALE:
+		if (val != 1)
+			return -EINVAL;
+
+		val = (val2 * 1024) / 15625;
+
+		switch (chan->type) {
+		case IIO_CAPACITANCE:
+			reg = AD7746_REG_CAP_GAINH;
+			break;
+		case IIO_VOLTAGE:
+			reg = AD7746_REG_VOLT_GAINH;
+			break;
+		default:
+			return -EINVAL;
+		}
+
+		mutex_lock(&chip->lock);
+		ret = i2c_smbus_write_word_swapped(chip->client, reg, val);
+		mutex_unlock(&chip->lock);
+		if (ret < 0)
+			return ret;
+
+		return 0;
+	case IIO_CHAN_INFO_CALIBBIAS:
+		if (val < 0 || val > 0xFFFF)
+			return -EINVAL;
+
+		mutex_lock(&chip->lock);
+		ret = i2c_smbus_write_word_swapped(chip->client,
+						   AD7746_REG_CAP_OFFH, val);
+		mutex_unlock(&chip->lock);
+		if (ret < 0)
+			return ret;
+
+		return 0;
+	case IIO_CHAN_INFO_OFFSET:
+	case IIO_CHAN_INFO_ZEROPOINT:
+		if (val < 0 || val > 43008000) /* 21pF */
+			return -EINVAL;
+
+		/*
+		 * CAPDAC Scale = 21pF_typ / 127
+		 * CIN Scale = 8.192pF / 2^24
+		 * Offset Scale = CAPDAC Scale / CIN Scale = 338646
+		 */
+
+		val /= 338646;
+		mutex_lock(&chip->lock);
+		chip->capdac[chan->channel][chan->differential] = val > 0 ?
+			FIELD_PREP(AD7746_CAPDAC_DACP_MASK, val) | AD7746_CAPDAC_DACEN : 0;
+
+		ret = ad7746_set_capdac(chip, chan->channel);
+		if (ret < 0) {
+			mutex_unlock(&chip->lock);
+			return ret;
+		}
+
+		chip->capdac_set = chan->channel;
+		mutex_unlock(&chip->lock);
+
+		return 0;
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		if (val2)
+			return -EINVAL;
+
+		switch (chan->type) {
+		case IIO_CAPACITANCE:
+			mutex_lock(&chip->lock);
+			ret = ad7746_store_cap_filter_rate_setup(chip, val);
+			mutex_unlock(&chip->lock);
+			return ret;
+		case IIO_VOLTAGE:
+			mutex_lock(&chip->lock);
+			ret = ad7746_store_vt_filter_rate_setup(chip, val);
+			mutex_unlock(&chip->lock);
+			return ret;
+		default:
+			return -EINVAL;
+		}
+	default:
+		return -EINVAL;
+	}
+}
+
+static const int ad7746_v_samp_freq[] = { 50, 31, 16, 8, };
+static const int ad7746_cap_samp_freq[] = { 91, 84, 50, 26, 16, 13, 11, 9, };
+
+static int ad7746_read_avail(struct iio_dev *indio_dev,
+			     struct iio_chan_spec const *chan, const int **vals,
+			     int *type, int *length, long mask)
+{
+	if (mask != IIO_CHAN_INFO_SAMP_FREQ)
+		return -EINVAL;
+
+	switch (chan->type) {
+	case IIO_VOLTAGE:
+		*vals = ad7746_v_samp_freq;
+		*length = ARRAY_SIZE(ad7746_v_samp_freq);
+		break;
+	case IIO_CAPACITANCE:
+		*vals = ad7746_cap_samp_freq;
+		*length = ARRAY_SIZE(ad7746_cap_samp_freq);
+		break;
+	default:
+		return -EINVAL;
+	}
+	*type = IIO_VAL_INT;
+	return IIO_AVAIL_LIST;
+}
+
+static int ad7746_read_channel(struct iio_dev *indio_dev,
+			       struct iio_chan_spec const *chan,
+			       int *val)
+{
+	struct ad7746_chip_info *chip = iio_priv(indio_dev);
+	int ret, delay;
+	u8 data[3];
+	u8 regval;
+
+	ret = ad7746_select_channel(indio_dev, chan);
+	if (ret < 0)
+		return ret;
+	delay = ret;
+
+	regval = chip->config | FIELD_PREP(AD7746_CONF_MODE_MASK,
+					   AD7746_CONF_MODE_SINGLE_CONV);
+	ret = i2c_smbus_write_byte_data(chip->client, AD7746_REG_CFG, regval);
+	if (ret < 0)
+		return ret;
+
+	msleep(delay);
+	/* Now read the actual register */
+	ret = i2c_smbus_read_i2c_block_data(chip->client,
+					    ad7746_chan_info[chan->address].addr,
+					    sizeof(data), data);
+	if (ret < 0)
+		return ret;
+
+	/*
+	 * Offset applied internally becaue the _offset userspace interface is
+	 * needed for the CAP DACs which apply a controllable offset.
+	 */
+	*val = get_unaligned_be24(data) - 0x800000;
+
+	return 0;
+}
+
+static int ad7746_read_raw(struct iio_dev *indio_dev,
+			   struct iio_chan_spec const *chan,
+			   int *val, int *val2,
+			   long mask)
+{
+	struct ad7746_chip_info *chip = iio_priv(indio_dev);
+	int ret, idx;
+	u8 reg;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		mutex_lock(&chip->lock);
+		ret = ad7746_read_channel(indio_dev, chan, val);
+		mutex_unlock(&chip->lock);
+		if (ret < 0)
+			return ret;
+
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_CALIBSCALE:
+		switch (chan->type) {
+		case IIO_CAPACITANCE:
+			reg = AD7746_REG_CAP_GAINH;
+			break;
+		case IIO_VOLTAGE:
+			reg = AD7746_REG_VOLT_GAINH;
+			break;
+		default:
+			return -EINVAL;
+		}
+
+		mutex_lock(&chip->lock);
+		ret = i2c_smbus_read_word_swapped(chip->client, reg);
+		mutex_unlock(&chip->lock);
+		if (ret < 0)
+			return ret;
+		/* 1 + gain_val / 2^16 */
+		*val = 1;
+		*val2 = (15625 * ret) / 1024;
+
+		return IIO_VAL_INT_PLUS_MICRO;
+	case IIO_CHAN_INFO_CALIBBIAS:
+		mutex_lock(&chip->lock);
+		ret = i2c_smbus_read_word_swapped(chip->client,
+						  AD7746_REG_CAP_OFFH);
+		mutex_unlock(&chip->lock);
+		if (ret < 0)
+			return ret;
+		*val = ret;
+
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_OFFSET:
+	case IIO_CHAN_INFO_ZEROPOINT:
+		*val = FIELD_GET(AD7746_CAPDAC_DACP_MASK,
+				 chip->capdac[chan->channel][chan->differential]) * 338646;
+
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_SCALE:
+		switch (chan->type) {
+		case IIO_CAPACITANCE:
+			/* 8.192pf / 2^24 */
+			*val =  0;
+			*val2 = 488;
+			return IIO_VAL_INT_PLUS_NANO;
+		case IIO_VOLTAGE:
+			/* 1170mV / 2^23 */
+			*val = 1170;
+			if (chan->channel == 1)
+				*val *= 6;
+			*val2 = 23;
+			return IIO_VAL_FRACTIONAL_LOG2;
+		case IIO_TEMP:
+			*val = 125;
+			*val2 = 8;
+			return IIO_VAL_FRACTIONAL_LOG2;
+		default:
+			return -EINVAL;
+		}
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		switch (chan->type) {
+		case IIO_CAPACITANCE:
+			idx = FIELD_GET(AD7746_CONF_CAPFS_MASK, chip->config);
+			*val = ad7746_cap_filter_rate_table[idx][0];
+			return IIO_VAL_INT;
+		case IIO_VOLTAGE:
+			idx = FIELD_GET(AD7746_CONF_VTFS_MASK, chip->config);
+			*val = ad7746_vt_filter_rate_table[idx][0];
+			return IIO_VAL_INT;
+		default:
+			return -EINVAL;
+		}
+	default:
+		return -EINVAL;
+	}
+}
+
+static const struct iio_info ad7746_info = {
+	.attrs = &ad7746_attribute_group,
+	.read_raw = ad7746_read_raw,
+	.read_avail = ad7746_read_avail,
+	.write_raw = ad7746_write_raw,
+};
+
+static int ad7746_probe(struct i2c_client *client,
+			const struct i2c_device_id *id)
+{
+	struct device *dev = &client->dev;
+	struct ad7746_chip_info *chip;
+	struct iio_dev *indio_dev;
+	unsigned char regval = 0;
+	unsigned int vdd_permille;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*chip));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	chip = iio_priv(indio_dev);
+	mutex_init(&chip->lock);
+
+	chip->client = client;
+	chip->capdac_set = -1;
+
+	indio_dev->name = id->name;
+	indio_dev->info = &ad7746_info;
+	indio_dev->channels = ad7746_channels;
+	if (id->driver_data == 7746)
+		indio_dev->num_channels = ARRAY_SIZE(ad7746_channels);
+	else
+		indio_dev->num_channels =  ARRAY_SIZE(ad7746_channels) - 2;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+
+	if (device_property_read_bool(dev, "adi,exca-output-en")) {
+		if (device_property_read_bool(dev, "adi,exca-output-invert"))
+			regval |= AD7746_EXCSETUP_NEXCA;
+		else
+			regval |= AD7746_EXCSETUP_EXCA;
+	}
+
+	if (device_property_read_bool(dev, "adi,excb-output-en")) {
+		if (device_property_read_bool(dev, "adi,excb-output-invert"))
+			regval |= AD7746_EXCSETUP_NEXCB;
+		else
+			regval |= AD7746_EXCSETUP_EXCB;
+	}
+
+	ret = device_property_read_u32(dev, "adi,excitation-vdd-permille",
+				       &vdd_permille);
+	if (!ret) {
+		switch (vdd_permille) {
+		case 125:
+			regval |= FIELD_PREP(AD7746_EXCSETUP_EXCLVL_MASK, 0);
+			break;
+		case 250:
+			regval |= FIELD_PREP(AD7746_EXCSETUP_EXCLVL_MASK, 1);
+			break;
+		case 375:
+			regval |= FIELD_PREP(AD7746_EXCSETUP_EXCLVL_MASK, 2);
+			break;
+		case 500:
+			regval |= FIELD_PREP(AD7746_EXCSETUP_EXCLVL_MASK, 3);
+			break;
+		default:
+			break;
+		}
+	}
+
+	ret = i2c_smbus_write_byte_data(chip->client, AD7746_REG_EXC_SETUP,
+					regval);
+	if (ret < 0)
+		return ret;
+
+	return devm_iio_device_register(indio_dev->dev.parent, indio_dev);
+}
+
+static const struct i2c_device_id ad7746_id[] = {
+	{ "ad7745", 7745 },
+	{ "ad7746", 7746 },
+	{ "ad7747", 7747 },
+	{}
+};
+MODULE_DEVICE_TABLE(i2c, ad7746_id);
+
+static const struct of_device_id ad7746_of_match[] = {
+	{ .compatible = "adi,ad7745" },
+	{ .compatible = "adi,ad7746" },
+	{ .compatible = "adi,ad7747" },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, ad7746_of_match);
+
+static struct i2c_driver ad7746_driver = {
+	.driver = {
+		.name = KBUILD_MODNAME,
+		.of_match_table = ad7746_of_match,
+	},
+	.probe = ad7746_probe,
+	.id_table = ad7746_id,
+};
+module_i2c_driver(ad7746_driver);
+
+MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
+MODULE_DESCRIPTION("Analog Devices AD7746/5/7 capacitive sensor driver");
+MODULE_LICENSE("GPL v2");