iio:cdc:ad7150: Move driver out of staging.

This capacitance to digital converter (CDC) driver is compliant with
the IIO ABI.  Note, not all features supported (e.g. window event modes)
but the driver should be in a useful functional state.

The cleanup was done against QEMU emulation of the device rather than
actual hardware.   Whilst this was a bit of an experiment, it made it
easy to confirm that the driver remained in a consistent working state
through the various refactors.  If it worked in the first place, it
should still be working after this cleanup.

Given some IIO drivers require expensive hardware setups, (not particularly
true with this one) the use of QEMU may provide a viable way forward
for providing testing during code changes where previously we'd had
to rely on sharp eyes and crossed fingers.

Note, no explicit MAINTAINERS entry as it will be covered by the
generic catch-alls for ADI and IIO drivers which are sufficient.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20210314181511.531414-25-jic23@kernel.org

5 files changed, 698 insertions, 0 deletions

diff --git a/drivers/iio/Kconfig b/drivers/iio/Kconfig
index b35e0c33b5e2..2334ad249b46 100644
--- a/drivers/iio/Kconfig
+++ b/drivers/iio/Kconfig
@@ -72,6 +72,7 @@ source "drivers/iio/accel/Kconfig"
 source "drivers/iio/adc/Kconfig"
 source "drivers/iio/afe/Kconfig"
 source "drivers/iio/amplifiers/Kconfig"
+source "drivers/iio/cdc/Kconfig"
 source "drivers/iio/chemical/Kconfig"
 source "drivers/iio/common/Kconfig"
 source "drivers/iio/dac/Kconfig"
diff --git a/drivers/iio/Makefile b/drivers/iio/Makefile
index 2561325aaa74..65e39bd4f934 100644
--- a/drivers/iio/Makefile
+++ b/drivers/iio/Makefile
@@ -18,6 +18,7 @@ obj-y += adc/
 obj-y += afe/
 obj-y += amplifiers/
 obj-y += buffer/
+obj-y += cdc/
 obj-y += chemical/
 obj-y += common/
 obj-y += dac/
diff --git a/drivers/iio/cdc/Kconfig b/drivers/iio/cdc/Kconfig
new file mode 100644
index 000000000000..5e3319a3ff48
--- /dev/null
+++ b/drivers/iio/cdc/Kconfig
@@ -0,0 +1,17 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# CDC drivers
+#
+menu "Capacitance to digital converters"
+
+config AD7150
+	tristate "Analog Devices ad7150/1/6 capacitive sensor driver"
+	depends on I2C
+	help
+	  Say yes here to build support for Analog Devices capacitive sensors.
+	  (ad7150, ad7151, ad7156) Provides direct access via sysfs.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called ad7150.
+
+endmenu
diff --git a/drivers/iio/cdc/Makefile b/drivers/iio/cdc/Makefile
new file mode 100644
index 000000000000..ee490637b032
--- /dev/null
+++ b/drivers/iio/cdc/Makefile
@@ -0,0 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for industrial I/O capacitance to digital converter (CDC) drivers
+#
+
+obj-$(CONFIG_AD7150) += ad7150.o
diff --git a/drivers/iio/cdc/ad7150.c b/drivers/iio/cdc/ad7150.c
new file mode 100644
index 000000000000..f9cce1a64586
--- /dev/null
+++ b/drivers/iio/cdc/ad7150.c
@@ -0,0 +1,673 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * AD7150 capacitive sensor driver supporting AD7150/1/6
+ *
+ * Copyright 2010-2011 Analog Devices Inc.
+ * Copyright 2021 Jonathan Cameron <Jonathan.Cameron@huawei.com>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/device.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/i2c.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mod_devicetable.h>
+#include <linux/regulator/consumer.h>
+#include <linux/slab.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/iio/events.h>
+
+#define AD7150_STATUS_REG		0
+#define   AD7150_STATUS_OUT1		BIT(3)
+#define   AD7150_STATUS_OUT2		BIT(5)
+#define AD7150_CH1_DATA_HIGH_REG	1
+#define AD7150_CH2_DATA_HIGH_REG	3
+#define AD7150_CH1_AVG_HIGH_REG		5
+#define AD7150_CH2_AVG_HIGH_REG		7
+#define AD7150_CH1_SENSITIVITY_REG	9
+#define AD7150_CH1_THR_HOLD_H_REG	9
+#define AD7150_CH1_TIMEOUT_REG		10
+#define   AD7150_CH_TIMEOUT_RECEDING	GENMASK(3, 0)
+#define   AD7150_CH_TIMEOUT_APPROACHING	GENMASK(7, 4)
+#define AD7150_CH1_SETUP_REG		11
+#define AD7150_CH2_SENSITIVITY_REG	12
+#define AD7150_CH2_THR_HOLD_H_REG	12
+#define AD7150_CH2_TIMEOUT_REG		13
+#define AD7150_CH2_SETUP_REG		14
+#define AD7150_CFG_REG			15
+#define   AD7150_CFG_FIX		BIT(7)
+#define   AD7150_CFG_THRESHTYPE_MSK	GENMASK(6, 5)
+#define   AD7150_CFG_TT_NEG		0x0
+#define   AD7150_CFG_TT_POS		0x1
+#define   AD7150_CFG_TT_IN_WINDOW	0x2
+#define   AD7150_CFG_TT_OUT_WINDOW	0x3
+#define AD7150_PD_TIMER_REG		16
+#define AD7150_CH1_CAPDAC_REG		17
+#define AD7150_CH2_CAPDAC_REG		18
+#define AD7150_SN3_REG			19
+#define AD7150_SN2_REG			20
+#define AD7150_SN1_REG			21
+#define AD7150_SN0_REG			22
+#define AD7150_ID_REG			23
+
+enum {
+	AD7150,
+	AD7151,
+};
+
+/**
+ * struct ad7150_chip_info - instance specific chip data
+ * @client: i2c client for this device
+ * @threshold: thresholds for simple capacitance value events
+ * @thresh_sensitivity: threshold for simple capacitance offset
+ *	from 'average' value.
+ * @thresh_timeout: a timeout, in samples from the moment an
+ *	adaptive threshold event occurs to when the average
+ *	value jumps to current value.  Note made up of two fields,
+ *      3:0 are for timeout receding - applies if below lower threshold
+ *      7:4 are for timeout approaching - applies if above upper threshold
+ * @state_lock: ensure consistent state of this structure wrt the
+ *	hardware.
+ * @interrupts: one or two interrupt numbers depending on device type.
+ * @int_enabled: is a given interrupt currently enabled.
+ * @type: threshold type
+ * @dir: threshold direction
+ */
+struct ad7150_chip_info {
+	struct i2c_client *client;
+	u16 threshold[2][2];
+	u8 thresh_sensitivity[2][2];
+	u8 thresh_timeout[2][2];
+	struct mutex state_lock;
+	int interrupts[2];
+	bool int_enabled[2];
+	enum iio_event_type type;
+	enum iio_event_direction dir;
+};
+
+static const u8 ad7150_addresses[][6] = {
+	{ AD7150_CH1_DATA_HIGH_REG, AD7150_CH1_AVG_HIGH_REG,
+	  AD7150_CH1_SETUP_REG, AD7150_CH1_THR_HOLD_H_REG,
+	  AD7150_CH1_SENSITIVITY_REG, AD7150_CH1_TIMEOUT_REG },
+	{ AD7150_CH2_DATA_HIGH_REG, AD7150_CH2_AVG_HIGH_REG,
+	  AD7150_CH2_SETUP_REG, AD7150_CH2_THR_HOLD_H_REG,
+	  AD7150_CH2_SENSITIVITY_REG, AD7150_CH2_TIMEOUT_REG },
+};
+
+static int ad7150_read_raw(struct iio_dev *indio_dev,
+			   struct iio_chan_spec const *chan,
+			   int *val,
+			   int *val2,
+			   long mask)
+{
+	struct ad7150_chip_info *chip = iio_priv(indio_dev);
+	int channel = chan->channel;
+	int ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		ret = i2c_smbus_read_word_swapped(chip->client,
+						  ad7150_addresses[channel][0]);
+		if (ret < 0)
+			return ret;
+		*val = ret >> 4;
+
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_AVERAGE_RAW:
+		ret = i2c_smbus_read_word_swapped(chip->client,
+						  ad7150_addresses[channel][1]);
+		if (ret < 0)
+			return ret;
+		*val = ret;
+
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_SCALE:
+		/*
+		 * Base units for capacitance are nano farads and the value
+		 * calculated from the datasheet formula is in picofarad
+		 * so multiply by 1000
+		 */
+		*val = 1000;
+		*val2 = 40944 >> 4; /* To match shift in _RAW */
+		return IIO_VAL_FRACTIONAL;
+	case IIO_CHAN_INFO_OFFSET:
+		*val = -(12288 >> 4); /* To match shift in _RAW */
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		/* Strangely same for both 1 and 2 chan parts */
+		*val = 100;
+		return IIO_VAL_INT;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int ad7150_read_event_config(struct iio_dev *indio_dev,
+				    const struct iio_chan_spec *chan,
+				    enum iio_event_type type,
+				    enum iio_event_direction dir)
+{
+	struct ad7150_chip_info *chip = iio_priv(indio_dev);
+	u8 threshtype;
+	bool thrfixed;
+	int ret;
+
+	ret = i2c_smbus_read_byte_data(chip->client, AD7150_CFG_REG);
+	if (ret < 0)
+		return ret;
+
+	threshtype = FIELD_GET(AD7150_CFG_THRESHTYPE_MSK, ret);
+
+	/*check if threshold mode is fixed or adaptive*/
+	thrfixed = FIELD_GET(AD7150_CFG_FIX, ret);
+
+	switch (type) {
+	case IIO_EV_TYPE_THRESH_ADAPTIVE:
+		if (dir == IIO_EV_DIR_RISING)
+			return !thrfixed && (threshtype == AD7150_CFG_TT_POS);
+		return !thrfixed && (threshtype == AD7150_CFG_TT_NEG);
+	case IIO_EV_TYPE_THRESH:
+		if (dir == IIO_EV_DIR_RISING)
+			return thrfixed && (threshtype == AD7150_CFG_TT_POS);
+		return thrfixed && (threshtype == AD7150_CFG_TT_NEG);
+	default:
+		break;
+	}
+	return -EINVAL;
+}
+
+/* state_lock should be held to ensure consistent state */
+static int ad7150_write_event_params(struct iio_dev *indio_dev,
+				     unsigned int chan,
+				     enum iio_event_type type,
+				     enum iio_event_direction dir)
+{
+	struct ad7150_chip_info *chip = iio_priv(indio_dev);
+	int rising = (dir == IIO_EV_DIR_RISING);
+
+	/* Only update value live, if parameter is in use */
+	if ((type != chip->type) || (dir != chip->dir))
+		return 0;
+
+	switch (type) {
+		/* Note completely different from the adaptive versions */
+	case IIO_EV_TYPE_THRESH: {
+		u16 value = chip->threshold[rising][chan];
+		return i2c_smbus_write_word_swapped(chip->client,
+						    ad7150_addresses[chan][3],
+						    value);
+	}
+	case IIO_EV_TYPE_THRESH_ADAPTIVE: {
+		int ret;
+		u8 sens, timeout;
+
+		sens = chip->thresh_sensitivity[rising][chan];
+		ret = i2c_smbus_write_byte_data(chip->client,
+						ad7150_addresses[chan][4],
+						sens);
+		if (ret)
+			return ret;
+
+		/*
+		 * Single timeout register contains timeouts for both
+		 * directions.
+		 */
+		timeout = FIELD_PREP(AD7150_CH_TIMEOUT_APPROACHING,
+				     chip->thresh_timeout[1][chan]);
+		timeout |= FIELD_PREP(AD7150_CH_TIMEOUT_RECEDING,
+				      chip->thresh_timeout[0][chan]);
+		return i2c_smbus_write_byte_data(chip->client,
+						 ad7150_addresses[chan][5],
+						 timeout);
+	}
+	default:
+		return -EINVAL;
+	}
+}
+
+static int ad7150_write_event_config(struct iio_dev *indio_dev,
+				     const struct iio_chan_spec *chan,
+				     enum iio_event_type type,
+				     enum iio_event_direction dir, int state)
+{
+	struct ad7150_chip_info *chip = iio_priv(indio_dev);
+	int ret;
+
+	/*
+	 * There is only a single shared control and no on chip
+	 * interrupt disables for the two interrupt lines.
+	 * So, enabling will switch the events configured to enable
+	 * whatever was most recently requested and if necessary enable_irq()
+	 * the interrupt and any disable will disable_irq() for that
+	 * channels interrupt.
+	 */
+	if (!state) {
+		if ((chip->int_enabled[chan->channel]) &&
+		    (type == chip->type) && (dir == chip->dir)) {
+			disable_irq(chip->interrupts[chan->channel]);
+			chip->int_enabled[chan->channel] = false;
+		}
+		return 0;
+	}
+
+	mutex_lock(&chip->state_lock);
+	if ((type != chip->type) || (dir != chip->dir)) {
+		int rising = (dir == IIO_EV_DIR_RISING);
+		u8 thresh_type, cfg, fixed;
+
+		/*
+		 * Need to temporarily disable both interrupts if
+		 * enabled - this is to avoid races around changing
+		 * config and thresholds.
+		 * Note enable/disable_irq() are reference counted so
+		 * no need to check if already enabled.
+		 */
+		disable_irq(chip->interrupts[0]);
+		disable_irq(chip->interrupts[1]);
+
+		ret = i2c_smbus_read_byte_data(chip->client, AD7150_CFG_REG);
+		if (ret < 0)
+			goto error_ret;
+
+		cfg = ret & ~(AD7150_CFG_THRESHTYPE_MSK | AD7150_CFG_FIX);
+
+		if (type == IIO_EV_TYPE_THRESH_ADAPTIVE)
+			fixed = 0;
+		else
+			fixed = 1;
+
+		if (rising)
+			thresh_type = AD7150_CFG_TT_POS;
+		else
+			thresh_type = AD7150_CFG_TT_NEG;
+
+		cfg |= FIELD_PREP(AD7150_CFG_FIX, fixed) |
+			FIELD_PREP(AD7150_CFG_THRESHTYPE_MSK, thresh_type);
+
+		ret = i2c_smbus_write_byte_data(chip->client, AD7150_CFG_REG,
+						cfg);
+		if (ret < 0)
+			goto error_ret;
+
+		/*
+		 * There is a potential race condition here, but not easy
+		 * to close given we can't disable the interrupt at the
+		 * chip side of things. Rely on the status bit.
+		 */
+		chip->type = type;
+		chip->dir = dir;
+
+		/* update control attributes */
+		ret = ad7150_write_event_params(indio_dev, chan->channel, type,
+						dir);
+		if (ret)
+			goto error_ret;
+		/* reenable any irq's we disabled whilst changing mode */
+		enable_irq(chip->interrupts[0]);
+		enable_irq(chip->interrupts[1]);
+	}
+	if (!chip->int_enabled[chan->channel]) {
+		enable_irq(chip->interrupts[chan->channel]);
+		chip->int_enabled[chan->channel] = true;
+	}
+
+error_ret:
+	mutex_unlock(&chip->state_lock);
+
+	return ret;
+}
+
+static int ad7150_read_event_value(struct iio_dev *indio_dev,
+				   const struct iio_chan_spec *chan,
+				   enum iio_event_type type,
+				   enum iio_event_direction dir,
+				   enum iio_event_info info,
+				   int *val, int *val2)
+{
+	struct ad7150_chip_info *chip = iio_priv(indio_dev);
+	int rising = (dir == IIO_EV_DIR_RISING);
+
+	/* Complex register sharing going on here */
+	switch (info) {
+	case IIO_EV_INFO_VALUE:
+		switch (type) {
+		case IIO_EV_TYPE_THRESH_ADAPTIVE:
+			*val = chip->thresh_sensitivity[rising][chan->channel];
+			return IIO_VAL_INT;
+		case IIO_EV_TYPE_THRESH:
+			*val = chip->threshold[rising][chan->channel];
+			return IIO_VAL_INT;
+		default:
+			return -EINVAL;
+		}
+	case IIO_EV_INFO_TIMEOUT:
+		*val = 0;
+		*val2 = chip->thresh_timeout[rising][chan->channel] * 10000;
+		return IIO_VAL_INT_PLUS_MICRO;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int ad7150_write_event_value(struct iio_dev *indio_dev,
+				    const struct iio_chan_spec *chan,
+				    enum iio_event_type type,
+				    enum iio_event_direction dir,
+				    enum iio_event_info info,
+				    int val, int val2)
+{
+	int ret;
+	struct ad7150_chip_info *chip = iio_priv(indio_dev);
+	int rising = (dir == IIO_EV_DIR_RISING);
+
+	mutex_lock(&chip->state_lock);
+	switch (info) {
+	case IIO_EV_INFO_VALUE:
+		switch (type) {
+		case IIO_EV_TYPE_THRESH_ADAPTIVE:
+			chip->thresh_sensitivity[rising][chan->channel] = val;
+			break;
+		case IIO_EV_TYPE_THRESH:
+			chip->threshold[rising][chan->channel] = val;
+			break;
+		default:
+			ret = -EINVAL;
+			goto error_ret;
+		}
+		break;
+	case IIO_EV_INFO_TIMEOUT: {
+		/*
+		 * Raw timeout is in cycles of 10 msecs as long as both
+		 * channels are enabled.
+		 * In terms of INT_PLUS_MICRO, that is in units of 10,000
+		 */
+		int timeout = val2 / 10000;
+
+		if (val != 0 || timeout < 0 || timeout > 15 || val2 % 10000) {
+			ret = -EINVAL;
+			goto error_ret;
+		}
+
+		chip->thresh_timeout[rising][chan->channel] = timeout;
+		break;
+	}
+	default:
+		ret = -EINVAL;
+		goto error_ret;
+	}
+
+	/* write back if active */
+	ret = ad7150_write_event_params(indio_dev, chan->channel, type, dir);
+
+error_ret:
+	mutex_unlock(&chip->state_lock);
+	return ret;
+}
+
+static const struct iio_event_spec ad7150_events[] = {
+	{
+		.type = IIO_EV_TYPE_THRESH,
+		.dir = IIO_EV_DIR_RISING,
+		.mask_separate = BIT(IIO_EV_INFO_VALUE) |
+			BIT(IIO_EV_INFO_ENABLE),
+	}, {
+		.type = IIO_EV_TYPE_THRESH,
+		.dir = IIO_EV_DIR_FALLING,
+		.mask_separate = BIT(IIO_EV_INFO_VALUE) |
+			BIT(IIO_EV_INFO_ENABLE),
+	}, {
+		.type = IIO_EV_TYPE_THRESH_ADAPTIVE,
+		.dir = IIO_EV_DIR_RISING,
+		.mask_separate = BIT(IIO_EV_INFO_VALUE) |
+			BIT(IIO_EV_INFO_ENABLE) |
+			BIT(IIO_EV_INFO_TIMEOUT),
+	}, {
+		.type = IIO_EV_TYPE_THRESH_ADAPTIVE,
+		.dir = IIO_EV_DIR_FALLING,
+		.mask_separate = BIT(IIO_EV_INFO_VALUE) |
+			BIT(IIO_EV_INFO_ENABLE) |
+			BIT(IIO_EV_INFO_TIMEOUT),
+	},
+};
+
+#define AD7150_CAPACITANCE_CHAN(_chan)	{			\
+		.type = IIO_CAPACITANCE,			\
+		.indexed = 1,					\
+		.channel = _chan,				\
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |	\
+		BIT(IIO_CHAN_INFO_AVERAGE_RAW),			\
+		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | \
+			BIT(IIO_CHAN_INFO_OFFSET),		\
+		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),\
+		.event_spec = ad7150_events,			\
+		.num_event_specs = ARRAY_SIZE(ad7150_events),	\
+	}
+
+#define AD7150_CAPACITANCE_CHAN_NO_IRQ(_chan)	{		\
+		.type = IIO_CAPACITANCE,			\
+		.indexed = 1,					\
+		.channel = _chan,				\
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |	\
+		BIT(IIO_CHAN_INFO_AVERAGE_RAW),			\
+		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | \
+			BIT(IIO_CHAN_INFO_OFFSET),		\
+		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),\
+	}
+
+static const struct iio_chan_spec ad7150_channels[] = {
+	AD7150_CAPACITANCE_CHAN(0),
+	AD7150_CAPACITANCE_CHAN(1),
+};
+
+static const struct iio_chan_spec ad7150_channels_no_irq[] = {
+	AD7150_CAPACITANCE_CHAN_NO_IRQ(0),
+	AD7150_CAPACITANCE_CHAN_NO_IRQ(1),
+};
+
+static const struct iio_chan_spec ad7151_channels[] = {
+	AD7150_CAPACITANCE_CHAN(0),
+};
+
+static const struct iio_chan_spec ad7151_channels_no_irq[] = {
+	AD7150_CAPACITANCE_CHAN_NO_IRQ(0),
+};
+
+static irqreturn_t __ad7150_event_handler(void *private, u8 status_mask,
+					  int channel)
+{
+	struct iio_dev *indio_dev = private;
+	struct ad7150_chip_info *chip = iio_priv(indio_dev);
+	s64 timestamp = iio_get_time_ns(indio_dev);
+	int int_status;
+
+	int_status = i2c_smbus_read_byte_data(chip->client, AD7150_STATUS_REG);
+	if (int_status < 0)
+		return IRQ_HANDLED;
+
+	if (!(int_status & status_mask))
+		return IRQ_HANDLED;
+
+	iio_push_event(indio_dev,
+		       IIO_UNMOD_EVENT_CODE(IIO_CAPACITANCE, channel,
+					    chip->type, chip->dir),
+		       timestamp);
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t ad7150_event_handler_ch1(int irq, void *private)
+{
+	return __ad7150_event_handler(private, AD7150_STATUS_OUT1, 0);
+}
+
+static irqreturn_t ad7150_event_handler_ch2(int irq, void *private)
+{
+	return __ad7150_event_handler(private, AD7150_STATUS_OUT2, 1);
+}
+
+static IIO_CONST_ATTR(in_capacitance_thresh_adaptive_timeout_available,
+		      "[0 0.01 0.15]");
+
+static struct attribute *ad7150_event_attributes[] = {
+	&iio_const_attr_in_capacitance_thresh_adaptive_timeout_available
+	.dev_attr.attr,
+	NULL,
+};
+
+static const struct attribute_group ad7150_event_attribute_group = {
+	.attrs = ad7150_event_attributes,
+	.name = "events",
+};
+
+static const struct iio_info ad7150_info = {
+	.event_attrs = &ad7150_event_attribute_group,
+	.read_raw = &ad7150_read_raw,
+	.read_event_config = &ad7150_read_event_config,
+	.write_event_config = &ad7150_write_event_config,
+	.read_event_value = &ad7150_read_event_value,
+	.write_event_value = &ad7150_write_event_value,
+};
+
+static const struct iio_info ad7150_info_no_irq = {
+	.read_raw = &ad7150_read_raw,
+};
+
+static void ad7150_reg_disable(void *data)
+{
+	struct regulator *reg = data;
+
+	regulator_disable(reg);
+}
+
+static int ad7150_probe(struct i2c_client *client,
+			const struct i2c_device_id *id)
+{
+	struct ad7150_chip_info *chip;
+	struct iio_dev *indio_dev;
+	struct regulator *reg;
+	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->state_lock);
+	chip->client = client;
+
+	indio_dev->name = id->name;
+
+	indio_dev->modes = INDIO_DIRECT_MODE;
+
+	reg = devm_regulator_get(&client->dev, "vdd");
+	if (IS_ERR(reg))
+		return PTR_ERR(reg);
+
+	ret = regulator_enable(reg);
+	if (ret)
+		return ret;
+
+	ret = devm_add_action_or_reset(&client->dev, ad7150_reg_disable, reg);
+	if (ret)
+		return ret;
+
+	chip->interrupts[0] = fwnode_irq_get(dev_fwnode(&client->dev), 0);
+	if (chip->interrupts[0] < 0)
+		return chip->interrupts[0];
+	if (id->driver_data == AD7150) {
+		chip->interrupts[1] = fwnode_irq_get(dev_fwnode(&client->dev), 1);
+		if (chip->interrupts[1] < 0)
+			return chip->interrupts[1];
+	}
+	if (chip->interrupts[0] &&
+	    (id->driver_data == AD7151 || chip->interrupts[1])) {
+		irq_set_status_flags(chip->interrupts[0], IRQ_NOAUTOEN);
+		ret = devm_request_threaded_irq(&client->dev,
+						chip->interrupts[0],
+						NULL,
+						&ad7150_event_handler_ch1,
+						IRQF_TRIGGER_RISING |
+						IRQF_ONESHOT,
+						"ad7150_irq1",
+						indio_dev);
+		if (ret)
+			return ret;
+
+		indio_dev->info = &ad7150_info;
+		switch (id->driver_data) {
+		case AD7150:
+			indio_dev->channels = ad7150_channels;
+			indio_dev->num_channels = ARRAY_SIZE(ad7150_channels);
+			irq_set_status_flags(chip->interrupts[1], IRQ_NOAUTOEN);
+			ret = devm_request_threaded_irq(&client->dev,
+							chip->interrupts[1],
+							NULL,
+							&ad7150_event_handler_ch2,
+							IRQF_TRIGGER_RISING |
+							IRQF_ONESHOT,
+							"ad7150_irq2",
+							indio_dev);
+			if (ret)
+				return ret;
+			break;
+		case AD7151:
+			indio_dev->channels = ad7151_channels;
+			indio_dev->num_channels = ARRAY_SIZE(ad7151_channels);
+			break;
+		default:
+			return -EINVAL;
+		}
+
+	} else {
+		indio_dev->info = &ad7150_info_no_irq;
+		switch (id->driver_data) {
+		case AD7150:
+			indio_dev->channels = ad7150_channels_no_irq;
+			indio_dev->num_channels =
+				ARRAY_SIZE(ad7150_channels_no_irq);
+			break;
+		case AD7151:
+			indio_dev->channels = ad7151_channels_no_irq;
+			indio_dev->num_channels =
+				ARRAY_SIZE(ad7151_channels_no_irq);
+			break;
+		default:
+			return -EINVAL;
+		}
+	}
+
+	return devm_iio_device_register(indio_dev->dev.parent, indio_dev);
+}
+
+static const struct i2c_device_id ad7150_id[] = {
+	{ "ad7150", AD7150 },
+	{ "ad7151", AD7151 },
+	{ "ad7156", AD7150 },
+	{}
+};
+
+MODULE_DEVICE_TABLE(i2c, ad7150_id);
+
+static const struct of_device_id ad7150_of_match[] = {
+	{ "adi,ad7150" },
+	{ "adi,ad7151" },
+	{ "adi,ad7156" },
+	{}
+};
+static struct i2c_driver ad7150_driver = {
+	.driver = {
+		.name = "ad7150",
+		.of_match_table = ad7150_of_match,
+	},
+	.probe = ad7150_probe,
+	.id_table = ad7150_id,
+};
+module_i2c_driver(ad7150_driver);
+
+MODULE_AUTHOR("Barry Song <21cnbao@gmail.com>");
+MODULE_DESCRIPTION("Analog Devices AD7150/1/6 capacitive sensor driver");
+MODULE_LICENSE("GPL v2");