iio: Add SEMTECH SX9310/9311 sensor driver

Add SEMTECH SX9310/9311 driver.

The device has the following entry points:

Usual frequency:
- sampling_frequency
- sampling_frequency_available

Instant reading of current values for different sensors:
- in_proximity0_raw
- in_proximity1_raw
- in_proximity2_raw
- in_proximity3_comb_raw
and associated events in events/

Signed-off-by: Gwendal Grignou <[e-mail]>
Signed-off-by: Enrico Granata <[e-mail]>
Signed-off-by: Daniel Campello <[e-mail]>
Signed-off-by: Jonathan Cameron <[e-mail]>

Documentation/ABI/testing/sysfs-bus-iio-sx9310

···
+What:		/sys/bus/iio/devices/iio:deviceX/in_proximity3_comb_raw
+Date:		February 2019
+KernelVersion:	5.6
+Contact:	Daniel Campello <[e-mail]>
+Description:
+		Proximity measurement indicating that some object is
+		near the combined sensor. The combined sensor presents
+		proximity measurements constructed by hardware by
+		combining measurements taken from a given set of
+		physical sensors.

drivers/iio/proximity/Kconfig

···
 	  To compile this driver as a module, choose M here: the
 	  module will be called srf04.
 
+config SX9310
+	tristate "SX9310/SX9311 Semtech proximity sensor"
+	select IIO_BUFFER
+	select IIO_TRIGGERED_BUFFER
+	select REGMAP_I2C
+	depends on I2C
+	help
+	  Say Y here to build a driver for Semtech's SX9310/SX9311 capacitive
+	  proximity/button sensor.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called sx9310.
+
 config SX9500
 	tristate "SX9500 Semtech proximity sensor"
 	select IIO_BUFFER

drivers/iio/proximity/Makefile

···
 obj-$(CONFIG_RFD77402)		+= rfd77402.o
 obj-$(CONFIG_SRF04)		+= srf04.o
 obj-$(CONFIG_SRF08)		+= srf08.o
+obj-$(CONFIG_SX9310)		+= sx9310.o
 obj-$(CONFIG_SX9500)		+= sx9500.o
 obj-$(CONFIG_VL53L0X_I2C)	+= vl53l0x-i2c.o
 

drivers/iio/proximity/sx9310.c

···
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2018 Google LLC.
+ *
+ * Driver for Semtech's SX9310/SX9311 capacitive proximity/button solution.
+ * Based on SX9500 driver and Semtech driver using the input framework
+ * <https://my.syncplicity.com/share/teouwsim8niiaud/
+ *          linux-driver-SX9310_NoSmartHSensing>.
+ * Reworked April 2019 by Evan Green <[e-mail]>
+ * and January 2020 by Daniel Campello <[e-mail]>
+ */
+
+#include <linux/acpi.h>
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/irq.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/pm.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+
+#include <linux/iio/buffer.h>
+#include <linux/iio/events.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/iio/trigger.h>
+#include <linux/iio/triggered_buffer.h>
+#include <linux/iio/trigger_consumer.h>
+
+/* Register definitions. */
+#define SX9310_REG_IRQ_SRC				0x00
+#define SX9310_REG_STAT0				0x01
+#define SX9310_REG_STAT1				0x02
+#define SX9310_REG_IRQ_MSK				0x03
+#define   SX9310_CONVDONE_IRQ				BIT(3)
+#define   SX9310_FAR_IRQ				BIT(5)
+#define   SX9310_CLOSE_IRQ				BIT(6)
+#define   SX9310_EVENT_IRQ				(SX9310_FAR_IRQ | \
+							 SX9310_CLOSE_IRQ)
+#define SX9310_REG_IRQ_FUNC				0x04
+
+#define SX9310_REG_PROX_CTRL0				0x10
+#define   SX9310_REG_PROX_CTRL0_PROXSTAT2		0x10
+#define   SX9310_REG_PROX_CTRL0_EN_MASK			0x0F
+#define SX9310_REG_PROX_CTRL1				0x11
+#define SX9310_REG_PROX_CTRL2				0x12
+#define   SX9310_REG_PROX_CTRL2_COMBMODE_ALL		0x80
+#define   SX9310_REG_PROX_CTRL2_SHIELDEN_DYNAMIC	0x04
+#define SX9310_REG_PROX_CTRL3				0x13
+#define   SX9310_REG_PROX_CTRL3_GAIN0_X8		0x0c
+#define   SX9310_REG_PROX_CTRL3_GAIN12_X4		0x02
+#define SX9310_REG_PROX_CTRL4				0x14
+#define   SX9310_REG_PROX_CTRL4_RESOLUTION_FINEST	0x07
+#define SX9310_REG_PROX_CTRL5				0x15
+#define   SX9310_REG_PROX_CTRL5_RANGE_SMALL		0xc0
+#define   SX9310_REG_PROX_CTRL5_STARTUPSENS_CS1		0x04
+#define   SX9310_REG_PROX_CTRL5_RAWFILT_1P25		0x02
+#define SX9310_REG_PROX_CTRL6				0x16
+#define   SX9310_REG_PROX_CTRL6_COMP_COMMON		0x20
+#define SX9310_REG_PROX_CTRL7				0x17
+#define   SX9310_REG_PROX_CTRL7_AVGNEGFILT_2		0x08
+#define   SX9310_REG_PROX_CTRL7_AVGPOSFILT_512		0x05
+#define SX9310_REG_PROX_CTRL8				0x18
+#define SX9310_REG_PROX_CTRL9				0x19
+#define   SX9310_REG_PROX_CTRL8_9_PTHRESH12_28		0x40
+#define   SX9310_REG_PROX_CTRL8_9_PTHRESH_96		0x88
+#define   SX9310_REG_PROX_CTRL8_9_BODYTHRESH_900	0x03
+#define   SX9310_REG_PROX_CTRL8_9_BODYTHRESH_1500	0x05
+#define SX9310_REG_PROX_CTRL10				0x1a
+#define   SX9310_REG_PROX_CTRL10_HYST_6PCT		0x10
+#define   SX9310_REG_PROX_CTRL10_CLOSE_DEBOUNCE_8	0x12
+#define   SX9310_REG_PROX_CTRL10_FAR_DEBOUNCE_8		0x03
+#define SX9310_REG_PROX_CTRL11				0x1b
+#define SX9310_REG_PROX_CTRL12				0x1c
+#define SX9310_REG_PROX_CTRL13				0x1d
+#define SX9310_REG_PROX_CTRL14				0x1e
+#define SX9310_REG_PROX_CTRL15				0x1f
+#define SX9310_REG_PROX_CTRL16				0x20
+#define SX9310_REG_PROX_CTRL17				0x21
+#define SX9310_REG_PROX_CTRL18				0x22
+#define SX9310_REG_PROX_CTRL19				0x23
+#define SX9310_REG_SAR_CTRL0				0x2a
+#define   SX9310_REG_SAR_CTRL0_SARDEB_4_SAMPLES		0x40
+#define   SX9310_REG_SAR_CTRL0_SARHYST_8		0x10
+#define SX9310_REG_SAR_CTRL1				0x2b
+/* Each increment of the slope register is 0.0078125. */
+#define   SX9310_REG_SAR_CTRL1_SLOPE(_hnslope)		(_hnslope / 78125)
+#define SX9310_REG_SAR_CTRL2				0x2c
+#define   SX9310_REG_SAR_CTRL2_SAROFFSET_DEFAULT	0x3c
+
+#define SX9310_REG_SENSOR_SEL				0x30
+
+#define SX9310_REG_USE_MSB				0x31
+#define SX9310_REG_USE_LSB				0x32
+
+#define SX9310_REG_AVG_MSB				0x33
+#define SX9310_REG_AVG_LSB				0x34
+
+#define SX9310_REG_DIFF_MSB				0x35
+#define SX9310_REG_DIFF_LSB				0x36
+
+#define SX9310_REG_OFFSET_MSB				0x37
+#define SX9310_REG_OFFSET_LSB				0x38
+
+#define SX9310_REG_SAR_MSB				0x39
+#define SX9310_REG_SAR_LSB				0x3a
+
+#define SX9310_REG_I2CADDR				0x40
+#define SX9310_REG_PAUSE				0x41
+#define SX9310_REG_WHOAMI				0x42
+#define   SX9310_WHOAMI_VALUE				0x01
+#define   SX9311_WHOAMI_VALUE				0x02
+
+#define SX9310_REG_RESET				0x7f
+#define   SX9310_SOFT_RESET				0xde
+
+#define SX9310_SCAN_PERIOD_MASK				GENMASK(7, 4)
+#define SX9310_SCAN_PERIOD_SHIFT			4
+
+#define SX9310_COMPSTAT_MASK				GENMASK(3, 0)
+
+/* 4 hardware channels, as defined in STAT0: COMB, CS2, CS1 and CS0. */
+#define SX9310_NUM_CHANNELS				4
+#define SX9310_CHAN_ENABLED_MASK			GENMASK(3, 0)
+
+struct sx9310_data {
+	/* Serialize access to registers and channel configuration */
+	struct mutex mutex;
+	struct i2c_client *client;
+	struct iio_trigger *trig;
+	struct regmap *regmap;
+	/*
+	 * Last reading of the proximity status for each channel.
+	 * We only send an event to user space when this changes.
+	 */
+	bool prox_stat[SX9310_NUM_CHANNELS];
+	bool trigger_enabled;
+	__be16 buffer[SX9310_NUM_CHANNELS +
+		      4]; /* 64-bit data + 64-bit timestamp */
+	/* Remember enabled channels and sample rate during suspend. */
+	unsigned int suspend_ctrl0;
+	struct completion completion;
+	unsigned int chan_read, chan_event;
+	int channel_users[SX9310_NUM_CHANNELS];
+	int whoami;
+};
+
+static const struct iio_event_spec sx9310_events[] = {
+	{
+		.type = IIO_EV_TYPE_THRESH,
+		.dir = IIO_EV_DIR_EITHER,
+		.mask_separate = BIT(IIO_EV_INFO_ENABLE),
+	},
+};
+
+#define SX9310_NAMED_CHANNEL(idx, name)					 \
+	{								 \
+		.type = IIO_PROXIMITY,					 \
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		 \
+		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ), \
+		.indexed = 1,						 \
+		.channel = idx,						 \
+		.extend_name = name,					 \
+		.address = SX9310_REG_DIFF_MSB,				 \
+		.event_spec = sx9310_events,				 \
+		.num_event_specs = ARRAY_SIZE(sx9310_events),		 \
+		.scan_index = idx,					 \
+		.scan_type = {						 \
+			.sign = 's',					 \
+			.realbits = 12,					 \
+			.storagebits = 16,				 \
+			.endianness = IIO_BE,				 \
+		},							 \
+	}
+#define SX9310_CHANNEL(idx) SX9310_NAMED_CHANNEL(idx, NULL)
+
+static const struct iio_chan_spec sx9310_channels[] = {
+	SX9310_CHANNEL(0),			/* CS0 */
+	SX9310_CHANNEL(1),			/* CS1 */
+	SX9310_CHANNEL(2),			/* CS2 */
+	SX9310_NAMED_CHANNEL(3, "comb"),	/* COMB */
+
+	IIO_CHAN_SOFT_TIMESTAMP(4),
+};
+
+/*
+ * Each entry contains the integer part (val) and the fractional part, in micro
+ * seconds. It conforms to the IIO output IIO_VAL_INT_PLUS_MICRO.
+ */
+static const struct {
+	int val;
+	int val2;
+} sx9310_samp_freq_table[] = {
+	{ 500, 0 }, /* 0000: Min (no idle time) */
+	{ 66, 666666 }, /* 0001: 15 ms */
+	{ 33, 333333 }, /* 0010: 30 ms (Typ.) */
+	{ 22, 222222 }, /* 0011: 45 ms */
+	{ 16, 666666 }, /* 0100: 60 ms */
+	{ 11, 111111 }, /* 0101: 90 ms */
+	{ 8, 333333 }, /* 0110: 120 ms */
+	{ 5, 0 }, /* 0111: 200 ms */
+	{ 2, 500000 }, /* 1000: 400 ms */
+	{ 1, 666666 }, /* 1001: 600 ms */
+	{ 1, 250000 }, /* 1010: 800 ms */
+	{ 1, 0 }, /* 1011: 1 s */
+	{ 0, 500000 }, /* 1100: 2 s */
+	{ 0, 333333 }, /* 1101: 3 s */
+	{ 0, 250000 }, /* 1110: 4 s */
+	{ 0, 200000 }, /* 1111: 5 s */
+};
+static const unsigned int sx9310_scan_period_table[] = {
+	2,   15,  30,  45,   60,   90,	 120,  200,
+	400, 600, 800, 1000, 2000, 3000, 4000, 5000,
+};
+
+static ssize_t sx9310_show_samp_freq_avail(struct device *dev,
+					   struct device_attribute *attr,
+					   char *buf)
+{
+	size_t len = 0;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(sx9310_samp_freq_table); i++)
+		len += scnprintf(buf + len, PAGE_SIZE - len, "%d.%d ",
+				 sx9310_samp_freq_table[i].val,
+				 sx9310_samp_freq_table[i].val2);
+	buf[len - 1] = '\n';
+	return len;
+}
+static IIO_DEV_ATTR_SAMP_FREQ_AVAIL(sx9310_show_samp_freq_avail);
+
+static const struct regmap_range sx9310_writable_reg_ranges[] = {
+	regmap_reg_range(SX9310_REG_IRQ_MSK, SX9310_REG_IRQ_FUNC),
+	regmap_reg_range(SX9310_REG_PROX_CTRL0, SX9310_REG_PROX_CTRL19),
+	regmap_reg_range(SX9310_REG_SAR_CTRL0, SX9310_REG_SAR_CTRL2),
+	regmap_reg_range(SX9310_REG_SENSOR_SEL, SX9310_REG_SENSOR_SEL),
+	regmap_reg_range(SX9310_REG_OFFSET_MSB, SX9310_REG_OFFSET_LSB),
+	regmap_reg_range(SX9310_REG_PAUSE, SX9310_REG_PAUSE),
+	regmap_reg_range(SX9310_REG_RESET, SX9310_REG_RESET),
+};
+
+static const struct regmap_access_table sx9310_writeable_regs = {
+	.yes_ranges = sx9310_writable_reg_ranges,
+	.n_yes_ranges = ARRAY_SIZE(sx9310_writable_reg_ranges),
+};
+
+static const struct regmap_range sx9310_readable_reg_ranges[] = {
+	regmap_reg_range(SX9310_REG_IRQ_SRC, SX9310_REG_IRQ_FUNC),
+	regmap_reg_range(SX9310_REG_PROX_CTRL0, SX9310_REG_PROX_CTRL19),
+	regmap_reg_range(SX9310_REG_SAR_CTRL0, SX9310_REG_SAR_CTRL2),
+	regmap_reg_range(SX9310_REG_SENSOR_SEL, SX9310_REG_SAR_LSB),
+	regmap_reg_range(SX9310_REG_I2CADDR, SX9310_REG_WHOAMI),
+	regmap_reg_range(SX9310_REG_RESET, SX9310_REG_RESET),
+};
+
+static const struct regmap_access_table sx9310_readable_regs = {
+	.yes_ranges = sx9310_readable_reg_ranges,
+	.n_yes_ranges = ARRAY_SIZE(sx9310_readable_reg_ranges),
+};
+
+static const struct regmap_range sx9310_volatile_reg_ranges[] = {
+	regmap_reg_range(SX9310_REG_IRQ_SRC, SX9310_REG_STAT1),
+	regmap_reg_range(SX9310_REG_USE_MSB, SX9310_REG_DIFF_LSB),
+	regmap_reg_range(SX9310_REG_SAR_MSB, SX9310_REG_SAR_LSB),
+	regmap_reg_range(SX9310_REG_RESET, SX9310_REG_RESET),
+};
+
+static const struct regmap_access_table sx9310_volatile_regs = {
+	.yes_ranges = sx9310_volatile_reg_ranges,
+	.n_yes_ranges = ARRAY_SIZE(sx9310_volatile_reg_ranges),
+};
+
+static const struct regmap_config sx9310_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+
+	.max_register = SX9310_REG_RESET,
+	.cache_type = REGCACHE_RBTREE,
+
+	.wr_table = &sx9310_writeable_regs,
+	.rd_table = &sx9310_readable_regs,
+	.volatile_table = &sx9310_volatile_regs,
+};
+
+static int sx9310_update_chan_en(struct sx9310_data *data,
+				 unsigned int chan_read,
+				 unsigned int chan_event)
+{
+	int ret;
+
+	if ((data->chan_read | data->chan_event) != (chan_read | chan_event)) {
+		ret = regmap_update_bits(data->regmap, SX9310_REG_PROX_CTRL0,
+					 SX9310_CHAN_ENABLED_MASK,
+					 chan_read | chan_event);
+		if (ret)
+			return ret;
+	}
+	data->chan_read = chan_read;
+	data->chan_event = chan_event;
+	return 0;
+}
+
+static int sx9310_get_read_channel(struct sx9310_data *data, int channel)
+{
+	return sx9310_update_chan_en(data, data->chan_read | BIT(channel),
+				     data->chan_event);
+}
+
+static int sx9310_put_read_channel(struct sx9310_data *data, int channel)
+{
+	return sx9310_update_chan_en(data, data->chan_read & ~BIT(channel),
+				     data->chan_event);
+}
+
+static int sx9310_get_event_channel(struct sx9310_data *data, int channel)
+{
+	return sx9310_update_chan_en(data, data->chan_read,
+				     data->chan_event | BIT(channel));
+}
+
+static int sx9310_put_event_channel(struct sx9310_data *data, int channel)
+{
+	return sx9310_update_chan_en(data, data->chan_read,
+				     data->chan_event & ~BIT(channel));
+}
+
+static int sx9310_enable_irq(struct sx9310_data *data, unsigned int irq)
+{
+	return regmap_update_bits(data->regmap, SX9310_REG_IRQ_MSK, irq, irq);
+}
+
+static int sx9310_disable_irq(struct sx9310_data *data, unsigned int irq)
+{
+	return regmap_update_bits(data->regmap, SX9310_REG_IRQ_MSK, irq, 0);
+}
+
+static int sx9310_read_prox_data(struct sx9310_data *data,
+				 const struct iio_chan_spec *chan, __be16 *val)
+{
+	int ret;
+
+	ret = regmap_write(data->regmap, SX9310_REG_SENSOR_SEL, chan->channel);
+	if (ret < 0)
+		return ret;
+
+	return regmap_bulk_read(data->regmap, chan->address, val, 2);
+}
+
+/*
+ * If we have no interrupt support, we have to wait for a scan period
+ * after enabling a channel to get a result.
+ */
+static int sx9310_wait_for_sample(struct sx9310_data *data)
+{
+	int ret;
+	unsigned int val;
+
+	ret = regmap_read(data->regmap, SX9310_REG_PROX_CTRL0, &val);
+	if (ret < 0)
+		return ret;
+
+	val = (val & SX9310_SCAN_PERIOD_MASK) >> SX9310_SCAN_PERIOD_SHIFT;
+
+	msleep(sx9310_scan_period_table[val]);
+
+	return 0;
+}
+
+static int sx9310_read_proximity(struct sx9310_data *data,
+				 const struct iio_chan_spec *chan, int *val)
+{
+	int ret = 0;
+	__be16 rawval;
+
+	mutex_lock(&data->mutex);
+
+	ret = sx9310_get_read_channel(data, chan->channel);
+	if (ret < 0)
+		goto out;
+
+	ret = sx9310_enable_irq(data, SX9310_CONVDONE_IRQ);
+	if (ret < 0)
+		goto out_put_channel;
+
+	mutex_unlock(&data->mutex);
+
+	if (data->client->irq > 0) {
+		ret = wait_for_completion_interruptible(&data->completion);
+		reinit_completion(&data->completion);
+	} else {
+		ret = sx9310_wait_for_sample(data);
+	}
+
+	mutex_lock(&data->mutex);
+
+	if (ret < 0)
+		goto out_disable_irq;
+
+	ret = sx9310_read_prox_data(data, chan, &rawval);
+	if (ret < 0)
+		goto out_disable_irq;
+
+	*val = sign_extend32(be16_to_cpu(rawval),
+			     (chan->address == SX9310_REG_DIFF_MSB ? 11 : 15));
+
+	ret = sx9310_disable_irq(data, SX9310_CONVDONE_IRQ);
+	if (ret < 0)
+		goto out_put_channel;
+
+	ret = sx9310_put_read_channel(data, chan->channel);
+	if (ret < 0)
+		goto out;
+
+	mutex_unlock(&data->mutex);
+
+	return IIO_VAL_INT;
+
+out_disable_irq:
+	sx9310_disable_irq(data, SX9310_CONVDONE_IRQ);
+out_put_channel:
+	sx9310_put_read_channel(data, chan->channel);
+out:
+	mutex_unlock(&data->mutex);
+
+	return ret;
+}
+
+static int sx9310_read_samp_freq(struct sx9310_data *data, int *val, int *val2)
+{
+	unsigned int regval;
+	int ret = regmap_read(data->regmap, SX9310_REG_PROX_CTRL0, &regval);
+
+	if (ret < 0)
+		return ret;
+
+	regval = (regval & SX9310_SCAN_PERIOD_MASK) >> SX9310_SCAN_PERIOD_SHIFT;
+	*val = sx9310_samp_freq_table[regval].val;
+	*val2 = sx9310_samp_freq_table[regval].val2;
+
+	return IIO_VAL_INT_PLUS_MICRO;
+}
+
+static int sx9310_read_raw(struct iio_dev *indio_dev,
+			   const struct iio_chan_spec *chan, int *val,
+			   int *val2, long mask)
+{
+	struct sx9310_data *data = iio_priv(indio_dev);
+	int ret;
+
+	if (chan->type != IIO_PROXIMITY)
+		return -EINVAL;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		ret = iio_device_claim_direct_mode(indio_dev);
+		if (ret)
+			return ret;
+
+		ret = sx9310_read_proximity(data, chan, val);
+		iio_device_release_direct_mode(indio_dev);
+		return ret;
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		return sx9310_read_samp_freq(data, val, val2);
+	default:
+		return -EINVAL;
+	}
+}
+
+static int sx9310_set_samp_freq(struct sx9310_data *data, int val, int val2)
+{
+	int i, ret;
+
+	for (i = 0; i < ARRAY_SIZE(sx9310_samp_freq_table); i++)
+		if (val == sx9310_samp_freq_table[i].val &&
+		    val2 == sx9310_samp_freq_table[i].val2)
+			break;
+
+	if (i == ARRAY_SIZE(sx9310_samp_freq_table))
+		return -EINVAL;
+
+	mutex_lock(&data->mutex);
+
+	ret = regmap_update_bits(data->regmap, SX9310_REG_PROX_CTRL0,
+				 SX9310_SCAN_PERIOD_MASK,
+				 i << SX9310_SCAN_PERIOD_SHIFT);
+
+	mutex_unlock(&data->mutex);
+
+	return ret;
+}
+
+static int sx9310_write_raw(struct iio_dev *indio_dev,
+			    const struct iio_chan_spec *chan, int val, int val2,
+			    long mask)
+{
+	struct sx9310_data *data = iio_priv(indio_dev);
+
+	if (chan->type != IIO_PROXIMITY)
+		return -EINVAL;
+
+	if (mask != IIO_CHAN_INFO_SAMP_FREQ)
+		return -EINVAL;
+
+	return sx9310_set_samp_freq(data, val, val2);
+}
+
+static irqreturn_t sx9310_irq_handler(int irq, void *private)
+{
+	struct iio_dev *indio_dev = private;
+	struct sx9310_data *data = iio_priv(indio_dev);
+
+	if (data->trigger_enabled)
+		iio_trigger_poll(data->trig);
+
+	/*
+	 * Even if no event is enabled, we need to wake the thread to
+	 * clear the interrupt state by reading SX9310_REG_IRQ_SRC.  It
+	 * is not possible to do that here because regmap_read takes a
+	 * mutex.
+	 */
+	return IRQ_WAKE_THREAD;
+}
+
+static void sx9310_push_events(struct iio_dev *indio_dev)
+{
+	int ret;
+	unsigned int val, chan;
+	struct sx9310_data *data = iio_priv(indio_dev);
+	s64 timestamp = iio_get_time_ns(indio_dev);
+
+	/* Read proximity state on all channels */
+	ret = regmap_read(data->regmap, SX9310_REG_STAT0, &val);
+	if (ret < 0) {
+		dev_err(&data->client->dev, "i2c transfer error in irq\n");
+		return;
+	}
+
+	for (chan = 0; chan < SX9310_NUM_CHANNELS; chan++) {
+		int dir;
+		u64 ev;
+		bool new_prox = val & BIT(chan);
+
+		if (!(data->chan_event & BIT(chan)))
+			continue;
+		if (new_prox == data->prox_stat[chan])
+			/* No change on this channel. */
+			continue;
+
+		dir = new_prox ? IIO_EV_DIR_FALLING : IIO_EV_DIR_RISING;
+		ev = IIO_UNMOD_EVENT_CODE(IIO_PROXIMITY, chan,
+					  IIO_EV_TYPE_THRESH, dir);
+
+		iio_push_event(indio_dev, ev, timestamp);
+		data->prox_stat[chan] = new_prox;
+	}
+}
+
+static irqreturn_t sx9310_irq_thread_handler(int irq, void *private)
+{
+	struct iio_dev *indio_dev = private;
+	struct sx9310_data *data = iio_priv(indio_dev);
+	int ret;
+	unsigned int val;
+
+	mutex_lock(&data->mutex);
+
+	ret = regmap_read(data->regmap, SX9310_REG_IRQ_SRC, &val);
+	if (ret < 0) {
+		dev_err(&data->client->dev, "i2c transfer error in irq\n");
+		goto out;
+	}
+
+	if (val & SX9310_EVENT_IRQ)
+		sx9310_push_events(indio_dev);
+
+	if (val & SX9310_CONVDONE_IRQ)
+		complete(&data->completion);
+
+out:
+	mutex_unlock(&data->mutex);
+
+	return IRQ_HANDLED;
+}
+
+static int sx9310_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 sx9310_data *data = iio_priv(indio_dev);
+
+	return !!(data->chan_event & BIT(chan->channel));
+}
+
+static int sx9310_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 sx9310_data *data = iio_priv(indio_dev);
+	int ret;
+
+	/* If the state hasn't changed, there's nothing to do. */
+	if (!!(data->chan_event & BIT(chan->channel)) == state)
+		return 0;
+
+	mutex_lock(&data->mutex);
+	if (state) {
+		ret = sx9310_get_event_channel(data, chan->channel);
+		if (ret < 0)
+			goto out_unlock;
+		if (!(data->chan_event & ~BIT(chan->channel))) {
+			ret = sx9310_enable_irq(data, SX9310_EVENT_IRQ);
+			if (ret < 0)
+				sx9310_put_event_channel(data, chan->channel);
+		}
+	} else {
+		ret = sx9310_put_event_channel(data, chan->channel);
+		if (ret < 0)
+			goto out_unlock;
+		if (!data->chan_event) {
+			ret = sx9310_disable_irq(data, SX9310_EVENT_IRQ);
+			if (ret < 0)
+				sx9310_get_event_channel(data, chan->channel);
+		}
+	}
+
+out_unlock:
+	mutex_unlock(&data->mutex);
+	return ret;
+}
+
+static struct attribute *sx9310_attributes[] = {
+	&iio_dev_attr_sampling_frequency_available.dev_attr.attr,
+	NULL,
+};
+
+static const struct attribute_group sx9310_attribute_group = {
+	.attrs = sx9310_attributes,
+};
+
+static const struct iio_info sx9310_info = {
+	.attrs = &sx9310_attribute_group,
+	.read_raw = sx9310_read_raw,
+	.write_raw = sx9310_write_raw,
+	.read_event_config = sx9310_read_event_config,
+	.write_event_config = sx9310_write_event_config,
+};
+
+static int sx9310_set_trigger_state(struct iio_trigger *trig, bool state)
+{
+	struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
+	struct sx9310_data *data = iio_priv(indio_dev);
+	int ret = 0;
+
+	mutex_lock(&data->mutex);
+
+	if (state)
+		ret = sx9310_enable_irq(data, SX9310_CONVDONE_IRQ);
+	else if (!data->chan_read)
+		ret = sx9310_disable_irq(data, SX9310_CONVDONE_IRQ);
+	if (ret < 0)
+		goto out;
+
+	data->trigger_enabled = state;
+
+out:
+	mutex_unlock(&data->mutex);
+
+	return ret;
+}
+
+static const struct iio_trigger_ops sx9310_trigger_ops = {
+	.set_trigger_state = sx9310_set_trigger_state,
+};
+
+static irqreturn_t sx9310_trigger_handler(int irq, void *private)
+{
+	struct iio_poll_func *pf = private;
+	struct iio_dev *indio_dev = pf->indio_dev;
+	struct sx9310_data *data = iio_priv(indio_dev);
+	__be16 val;
+	int bit, ret, i = 0;
+
+	mutex_lock(&data->mutex);
+
+	for_each_set_bit(bit, indio_dev->active_scan_mask,
+			 indio_dev->masklength) {
+		ret = sx9310_read_prox_data(data, &indio_dev->channels[bit],
+					    &val);
+		if (ret < 0)
+			goto out;
+
+		data->buffer[i++] = val;
+	}
+
+	iio_push_to_buffers_with_timestamp(indio_dev, data->buffer,
+					   pf->timestamp);
+
+out:
+	mutex_unlock(&data->mutex);
+
+	iio_trigger_notify_done(indio_dev->trig);
+
+	return IRQ_HANDLED;
+}
+
+static int sx9310_buffer_preenable(struct iio_dev *indio_dev)
+{
+	struct sx9310_data *data = iio_priv(indio_dev);
+	unsigned int channels = 0;
+	int bit, ret;
+
+	mutex_lock(&data->mutex);
+	for_each_set_bit(bit, indio_dev->active_scan_mask,
+			 indio_dev->masklength)
+		channels |= BIT(indio_dev->channels[bit].channel);
+
+	ret = sx9310_update_chan_en(data, channels, data->chan_event);
+	mutex_unlock(&data->mutex);
+	return ret;
+}
+
+static int sx9310_buffer_postdisable(struct iio_dev *indio_dev)
+{
+	struct sx9310_data *data = iio_priv(indio_dev);
+	int ret;
+
+	mutex_lock(&data->mutex);
+	ret = sx9310_update_chan_en(data, 0, data->chan_event);
+	mutex_unlock(&data->mutex);
+	return ret;
+}
+
+static const struct iio_buffer_setup_ops sx9310_buffer_setup_ops = {
+	.preenable = sx9310_buffer_preenable,
+	.postenable = iio_triggered_buffer_postenable,
+	.predisable = iio_triggered_buffer_predisable,
+	.postdisable = sx9310_buffer_postdisable,
+};
+
+struct sx9310_reg_default {
+	u8 reg;
+	u8 def;
+};
+
+#define SX_INIT(_reg, _def)			\
+	{					\
+		.reg = SX9310_REG_##_reg,	\
+		.def = _def,			\
+	}
+
+static const struct sx9310_reg_default sx9310_default_regs[] = {
+	SX_INIT(IRQ_MSK, 0x00),
+	SX_INIT(IRQ_FUNC, 0x00),
+	/*
+	 * The lower 4 bits should not be set as it enable sensors measurements.
+	 * Turning the detection on before the configuration values are set to
+	 * good values can cause the device to return erroneous readings.
+	 */
+	SX_INIT(PROX_CTRL0, SX9310_REG_PROX_CTRL0_PROXSTAT2),
+	SX_INIT(PROX_CTRL1, 0x00),
+	SX_INIT(PROX_CTRL2, SX9310_REG_PROX_CTRL2_COMBMODE_ALL |
+			    SX9310_REG_PROX_CTRL2_SHIELDEN_DYNAMIC),
+	SX_INIT(PROX_CTRL3, SX9310_REG_PROX_CTRL3_GAIN0_X8 |
+			    SX9310_REG_PROX_CTRL3_GAIN12_X4),
+	SX_INIT(PROX_CTRL4, SX9310_REG_PROX_CTRL4_RESOLUTION_FINEST),
+	SX_INIT(PROX_CTRL5, SX9310_REG_PROX_CTRL5_RANGE_SMALL |
+			    SX9310_REG_PROX_CTRL5_STARTUPSENS_CS1 |
+			    SX9310_REG_PROX_CTRL5_RAWFILT_1P25),
+	SX_INIT(PROX_CTRL6, SX9310_REG_PROX_CTRL6_COMP_COMMON),
+	SX_INIT(PROX_CTRL7, SX9310_REG_PROX_CTRL7_AVGNEGFILT_2 |
+			    SX9310_REG_PROX_CTRL7_AVGPOSFILT_512),
+	SX_INIT(PROX_CTRL8, SX9310_REG_PROX_CTRL8_9_PTHRESH_96 |
+			    SX9310_REG_PROX_CTRL8_9_BODYTHRESH_1500),
+	SX_INIT(PROX_CTRL9, SX9310_REG_PROX_CTRL8_9_PTHRESH12_28 |
+			    SX9310_REG_PROX_CTRL8_9_BODYTHRESH_900),
+	SX_INIT(PROX_CTRL10, SX9310_REG_PROX_CTRL10_HYST_6PCT |
+			     SX9310_REG_PROX_CTRL10_CLOSE_DEBOUNCE_8 |
+			     SX9310_REG_PROX_CTRL10_FAR_DEBOUNCE_8),
+	SX_INIT(PROX_CTRL11, 0x00),
+	SX_INIT(PROX_CTRL12, 0x00),
+	SX_INIT(PROX_CTRL13, 0x00),
+	SX_INIT(PROX_CTRL14, 0x00),
+	SX_INIT(PROX_CTRL15, 0x00),
+	SX_INIT(PROX_CTRL16, 0x00),
+	SX_INIT(PROX_CTRL17, 0x00),
+	SX_INIT(PROX_CTRL18, 0x00),
+	SX_INIT(PROX_CTRL19, 0x00),
+	SX_INIT(SAR_CTRL0, SX9310_REG_SAR_CTRL0_SARDEB_4_SAMPLES |
+			   SX9310_REG_SAR_CTRL0_SARHYST_8),
+	SX_INIT(SAR_CTRL1, SX9310_REG_SAR_CTRL1_SLOPE(10781250)),
+	SX_INIT(SAR_CTRL2, SX9310_REG_SAR_CTRL2_SAROFFSET_DEFAULT),
+};
+
+/* Activate all channels and perform an initial compensation. */
+static int sx9310_init_compensation(struct iio_dev *indio_dev)
+{
+	struct sx9310_data *data = iio_priv(indio_dev);
+	int i, ret;
+	unsigned int val;
+	unsigned int ctrl0;
+
+	ret = regmap_read(data->regmap, SX9310_REG_PROX_CTRL0, &ctrl0);
+	if (ret < 0)
+		return ret;
+
+	/* run the compensation phase on all channels */
+	ret = regmap_write(data->regmap, SX9310_REG_PROX_CTRL0,
+			   ctrl0 | SX9310_REG_PROX_CTRL0_EN_MASK);
+	if (ret < 0)
+		return ret;
+
+	for (i = 100; i >= 0; i--) {
+		msleep(20);
+		ret = regmap_read(data->regmap, SX9310_REG_STAT1, &val);
+		if (ret < 0)
+			goto out;
+		if (!(val & SX9310_COMPSTAT_MASK))
+			break;
+	}
+
+	if (i < 0) {
+		dev_err(&data->client->dev,
+			"initial compensation timed out: 0x%02x", val);
+		ret = -ETIMEDOUT;
+	}
+
+out:
+	regmap_write(data->regmap, SX9310_REG_PROX_CTRL0, ctrl0);
+	return ret;
+}
+
+static int sx9310_init_device(struct iio_dev *indio_dev)
+{
+	struct sx9310_data *data = iio_priv(indio_dev);
+	const struct sx9310_reg_default *initval;
+	int ret;
+	unsigned int i, val;
+
+	ret = regmap_write(data->regmap, SX9310_REG_RESET, SX9310_SOFT_RESET);
+	if (ret < 0)
+		return ret;
+
+	usleep_range(1000, 2000); /* power-up time is ~1ms. */
+
+	/* Clear reset interrupt state by reading SX9310_REG_IRQ_SRC. */
+	ret = regmap_read(data->regmap, SX9310_REG_IRQ_SRC, &val);
+	if (ret < 0)
+		return ret;
+
+	/* Program some sane defaults. */
+	for (i = 0; i < ARRAY_SIZE(sx9310_default_regs); i++) {
+		initval = &sx9310_default_regs[i];
+		ret = regmap_write(data->regmap, initval->reg, initval->def);
+		if (ret < 0)
+			return ret;
+	}
+
+	return sx9310_init_compensation(indio_dev);
+}
+
+static int sx9310_set_indio_dev_name(struct device *dev,
+				     struct iio_dev *indio_dev,
+				     const struct i2c_device_id *id, int whoami)
+{
+	const struct acpi_device_id *acpi_id;
+
+	/* id will be NULL when enumerated via ACPI */
+	if (id) {
+		if (id->driver_data != whoami)
+			dev_err(dev, "WHOAMI does not match i2c_device_id: %s",
+				id->name);
+	} else if (ACPI_HANDLE(dev)) {
+		acpi_id = acpi_match_device(dev->driver->acpi_match_table, dev);
+		if (!acpi_id)
+			return -ENODEV;
+		if (acpi_id->driver_data != whoami)
+			dev_err(dev, "WHOAMI does not match acpi_device_id: %s",
+				acpi_id->id);
+	} else
+		return -ENODEV;
+
+	switch (whoami) {
+	case SX9310_WHOAMI_VALUE:
+		indio_dev->name = "sx9310";
+		break;
+	case SX9311_WHOAMI_VALUE:
+		indio_dev->name = "sx9311";
+		break;
+	default:
+		dev_err(dev, "unexpected WHOAMI response: %u", whoami);
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+static int sx9310_probe(struct i2c_client *client,
+			const struct i2c_device_id *id)
+{
+	int ret;
+	struct iio_dev *indio_dev;
+	struct sx9310_data *data;
+
+	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
+	if (indio_dev == NULL)
+		return -ENOMEM;
+
+	data = iio_priv(indio_dev);
+	data->client = client;
+	mutex_init(&data->mutex);
+	init_completion(&data->completion);
+
+	data->regmap = devm_regmap_init_i2c(client, &sx9310_regmap_config);
+	if (IS_ERR(data->regmap))
+		return PTR_ERR(data->regmap);
+
+	ret = regmap_read(data->regmap, SX9310_REG_WHOAMI, &data->whoami);
+	if (ret < 0) {
+		dev_err(&client->dev, "error in reading WHOAMI register: %d",
+			ret);
+		return ret;
+	}
+
+	ret = sx9310_set_indio_dev_name(&client->dev, indio_dev, id,
+					data->whoami);
+	if (ret < 0)
+		return ret;
+
+	ACPI_COMPANION_SET(&indio_dev->dev, ACPI_COMPANION(&client->dev));
+	indio_dev->dev.parent = &client->dev;
+	indio_dev->channels = sx9310_channels;
+	indio_dev->num_channels = ARRAY_SIZE(sx9310_channels);
+	indio_dev->info = &sx9310_info;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	i2c_set_clientdata(client, indio_dev);
+
+	ret = sx9310_init_device(indio_dev);
+	if (ret < 0)
+		return ret;
+
+	if (client->irq) {
+		ret = devm_request_threaded_irq(&client->dev, client->irq,
+						sx9310_irq_handler,
+						sx9310_irq_thread_handler,
+						IRQF_TRIGGER_LOW | IRQF_ONESHOT,
+						"sx9310_event", indio_dev);
+		if (ret < 0)
+			return ret;
+
+		data->trig =
+			devm_iio_trigger_alloc(&client->dev, "%s-dev%d",
+					       indio_dev->name, indio_dev->id);
+		if (!data->trig)
+			return -ENOMEM;
+
+		data->trig->dev.parent = &client->dev;
+		data->trig->ops = &sx9310_trigger_ops;
+		iio_trigger_set_drvdata(data->trig, indio_dev);
+
+		ret = devm_iio_trigger_register(&client->dev, data->trig);
+		if (ret)
+			return ret;
+	}
+
+	ret = devm_iio_triggered_buffer_setup(&client->dev, indio_dev,
+					      iio_pollfunc_store_time,
+					      sx9310_trigger_handler,
+					      &sx9310_buffer_setup_ops);
+	if (ret < 0)
+		return ret;
+
+	return devm_iio_device_register(&client->dev, indio_dev);
+}
+
+static int __maybe_unused sx9310_suspend(struct device *dev)
+{
+	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
+	struct sx9310_data *data = iio_priv(indio_dev);
+	u8 ctrl0;
+	int ret;
+
+	disable_irq_nosync(data->client->irq);
+
+	mutex_lock(&data->mutex);
+	ret = regmap_read(data->regmap, SX9310_REG_PROX_CTRL0,
+			  &data->suspend_ctrl0);
+
+	if (ret)
+		goto out;
+
+	ctrl0 = data->suspend_ctrl0 & ~SX9310_REG_PROX_CTRL0_EN_MASK;
+	ret = regmap_write(data->regmap, SX9310_REG_PROX_CTRL0, ctrl0);
+	if (ret)
+		goto out;
+
+	ret = regmap_write(data->regmap, SX9310_REG_PAUSE, 0);
+
+out:
+	mutex_unlock(&data->mutex);
+	return ret;
+}
+
+static int __maybe_unused sx9310_resume(struct device *dev)
+{
+	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
+	struct sx9310_data *data = iio_priv(indio_dev);
+	int ret;
+
+	mutex_lock(&data->mutex);
+	ret = regmap_write(data->regmap, SX9310_REG_PAUSE, 1);
+	if (ret)
+		goto out;
+
+	ret = regmap_write(data->regmap, SX9310_REG_PROX_CTRL0,
+			   data->suspend_ctrl0);
+
+out:
+	mutex_unlock(&data->mutex);
+
+	enable_irq(data->client->irq);
+
+	return ret;
+}
+
+static const struct dev_pm_ops sx9310_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(sx9310_suspend, sx9310_resume)
+};
+
+static const struct acpi_device_id sx9310_acpi_match[] = {
+	{ "STH9310", SX9310_WHOAMI_VALUE },
+	{ "STH9311", SX9311_WHOAMI_VALUE },
+	{},
+};
+MODULE_DEVICE_TABLE(acpi, sx9310_acpi_match);
+
+static const struct of_device_id sx9310_of_match[] = {
+	{ .compatible = "semtech,sx9310" },
+	{ .compatible = "semtech,sx9311" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, sx9310_of_match);
+
+static const struct i2c_device_id sx9310_id[] = {
+	{ "sx9310", SX9310_WHOAMI_VALUE },
+	{ "sx9311", SX9311_WHOAMI_VALUE },
+	{},
+};
+MODULE_DEVICE_TABLE(i2c, sx9310_id);
+
+static struct i2c_driver sx9310_driver = {
+	.driver = {
+		.name	= "sx9310",
+		.acpi_match_table = ACPI_PTR(sx9310_acpi_match),
+		.of_match_table = of_match_ptr(sx9310_of_match),
+		.pm = &sx9310_pm_ops,
+	},
+	.probe		= sx9310_probe,
+	.id_table	= sx9310_id,
+};
+module_i2c_driver(sx9310_driver);
+
+MODULE_AUTHOR("Gwendal Grignou <[e-mail]>");
+MODULE_AUTHOR("Daniel Campello <[e-mail]>");
+MODULE_DESCRIPTION("Driver for Semtech SX9310/SX9311 proximity sensor");
+MODULE_LICENSE("GPL v2");