Merge tag 'iio-for-6.9a' of http://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio into char-misc-next

Jonathan writes:

IIO: 1st set of new device support, features and cleanup for 6.9

IIO Backend support
===================

New approach from Nuno Sa to the problem of reuse of drivers with
IIO devices that are actually the combination of a highspeed chip
and an FPGA core handling the data capture and flows. It will hopefully
also apply to some other split designs. The ad9467 and axi-adi drivers
are converted over to this framework.

New device support
==================

adi,admfm2000
- New driver for this dual microwave down converter.
ams,as73211
- Add support for as7331 UV sensor.
richtek,rtq6056
- Add support for related parts RTQ6053 and RTQ6059
st,lsm6dsx
- Add ASM330LHHXG1 accelerometer and gyro support (mainly IDs)
ti,ads1298
- New driver for this medical ADC.

Features
========

tests
- Unit tests for the gain-time-scale helper library.
bosch,bmi088
- I2C support.
bosh,bmi160
- Add 10EC5280 ACPI ID. Used in a number of devices that won't get fixed.
  The ID is actually a PCI ID belonging to realtech. No response was received
  to earlier attempts to notify them of this.
  The manufacturers of some devices have replied to say they will not fix
  this incorrect ID. Add the ID and hope it isn't a problem.
bosch,bmi323
- Add BOSC0200 ACPI ID. Note this is a duplicate of one in the bmc150
  driver (it appears these parts share a windows driver).
  Both drivers perform an ID check that is safe on the other part before
  successfully probing.
hid-sensors-als
- Add color temperature and chromaticity support. Note this is a replacement
  for the series reverted in 6.8 that correctly handles all the potential
  channel combinations.
honeywell,hsc030pa
- Triggered buffer support (after driver cleanup).
honeywell,mprls00025pa
- Improved error handling.
- New DT binding to allow use of part number triplet as provided in data sheet
  to specify equivalent of most of the binding more efficiently.
- SPI support.
memsic,mxc4005
- ACPI ID MDA6655 as seen in the Chuwi Minibook X 2023
ti,hdc3020
- Add threshold event support (after some driver cleanup)
veml,vcnl4000
- Switch to high resolution proximity measurement.

Cleanup
=======
Various minor typo fixes and better use of defines etc.

Treewide
- Stop using ACPI_PTR(). The savings in space are small and not worth
  the complexity of __maybe_unused of ifdef guards.  To avoid use in
  new IIO drivers based on copy and paste, clean it out.
- cleanup.h based handling of iio_device_claim_direct_mode()/
  iio_device_release_direct_mode() using scope_cond_guard().
  In many drivers this is combined with other automated cleanup
  to give maximum simplifications.
  An initial set of drivers are converted over to this infrastructure.

Tools
- Use rewinddir() instead of seekdir() to return to start of file.

core
- Make iio_bus_type constant.

adi,ad16475
- Use irq_get_trigger_type() instead of opencoding.
adi,ad16480
- Use irq_get_trigger_type() instead of opencoding.
adi,ad-sigma-delta
- Avoid overwriting IRQ flags if provided by firmware.
ams,as73211
- Use IIO_VAL_FRACTIONAL for scales to simplify the code and potentially
  improve accuracy.
gts-library
- Use a div64_u64() instead of a loop to do a division.
honeywell,mprls00025pa
- Clean up dt-binding doc.
- Drop defaults when DT binding not providing values. Very unlikely
  these were useful given they were wrong for vast majority of supported
  devices.
- Whitespace cleanup
miramems,da280
- Use i2c_get_match_data() to replace hand rolled ACPI matching code.
semtech,sx9324
- Avoid unnecessary copying of property strings.
st,lsm6dsx
- Improve docs, particularly wrt to making addition of new device
  support less noisy.
st,lsm9ds0
- Use dev_err_probe() in all probe() error handling.
- Improved header includes.
- Tidy up termination of ID tables.
ti,ads1014
- Correct upper bound on PGA (wrong value had no actual impact)
ti,afe4403/4404
- devm_ useage to simplify error handling in probe() and allow() remove to
  be dropped.
voltage-divider
- Add dt-binding for io-channel-cells to allow such a device to be both
  an IIO consumer and IIO producer at the same time.

* tag 'iio-for-6.9a' of http://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio: (106 commits)
  iio: imu: bmi323: Add ACPI Match Table
  iio: accel: bmc150: Document duplicate ACPI entries with bmi323 driver
  iio: adc: ti-ads1298: Add driver
  dt-bindings: iio: adc: ti-ads1298: Add bindings
  iio: pressure: hsc030pa add triggered buffer
  iio: pressure: hsc030pa add mandatory delay
  iio: pressure: hsc030pa: update datasheet URLs
  iio: pressure: hsc030pa: include cleanup
  iio: pressure: hsc030pa: use signed type to hold div_64() result
  dt-bindings: iio: pressure: honeywell,hsc030pa.yaml add spi props
  iio: st_sensors: lsm9ds0: Use common style for terminator in ID tables
  iio: st_sensors: lsm9ds0: Don't use "proxy" headers
  iio: st_sensors: lsm9ds0: Use dev_err_probe() everywhere
  iio: adc: adi-axi-adc: move to backend framework
  iio: adc: ad9467: convert to backend framework
  iio: add the IIO backend framework
  iio: buffer-dmaengine: export buffer alloc and free functions
  of: property: add device link support for io-backends
  dt-bindings: adc: axi-adc: update bindings for backend framework
  dt-bindings: adc: ad9467: add new io-backend property
  ...

2 files changed, 311 insertions, 138 deletions

diff --git a/drivers/iio/humidity/hdc3020.c b/drivers/iio/humidity/hdc3020.c
index ed70415512f6..1e5d0d4797b1 100644
--- a/drivers/iio/humidity/hdc3020.c
+++ b/drivers/iio/humidity/hdc3020.c
@@ -5,41 +5,66 @@
  *
  * Copyright (C) 2023
  *
+ * Copyright (C) 2024 Liebherr-Electronics and Drives GmbH
+ *
  * Datasheet: https://www.ti.com/lit/ds/symlink/hdc3020.pdf
  */
 
+#include <linux/bitfield.h>
 #include <linux/bitops.h>
 #include <linux/cleanup.h>
 #include <linux/crc8.h>
 #include <linux/delay.h>
 #include <linux/i2c.h>
 #include <linux/init.h>
+#include <linux/interrupt.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
+#include <linux/units.h>
 
 #include <asm/unaligned.h>
 
+#include <linux/iio/events.h>
 #include <linux/iio/iio.h>
 
-#define HDC3020_HEATER_CMD_MSB		0x30 /* shared by all heater commands */
-#define HDC3020_HEATER_ENABLE		0x6D
-#define HDC3020_HEATER_DISABLE		0x66
-#define HDC3020_HEATER_CONFIG		0x6E
+#define HDC3020_S_AUTO_10HZ_MOD0	0x2737
+#define HDC3020_S_STATUS		0x3041
+#define HDC3020_HEATER_DISABLE		0x3066
+#define HDC3020_HEATER_ENABLE		0x306D
+#define HDC3020_HEATER_CONFIG		0x306E
+#define HDC3020_EXIT_AUTO		0x3093
+#define HDC3020_S_T_RH_THRESH_LOW	0x6100
+#define HDC3020_S_T_RH_THRESH_LOW_CLR	0x610B
+#define HDC3020_S_T_RH_THRESH_HIGH_CLR	0x6116
+#define HDC3020_S_T_RH_THRESH_HIGH	0x611D
+#define HDC3020_R_T_RH_AUTO		0xE000
+#define HDC3020_R_T_LOW_AUTO		0xE002
+#define HDC3020_R_T_HIGH_AUTO		0xE003
+#define HDC3020_R_RH_LOW_AUTO		0xE004
+#define HDC3020_R_RH_HIGH_AUTO		0xE005
+#define HDC3020_R_T_RH_THRESH_LOW	0xE102
+#define HDC3020_R_T_RH_THRESH_LOW_CLR	0xE109
+#define HDC3020_R_T_RH_THRESH_HIGH_CLR	0xE114
+#define HDC3020_R_T_RH_THRESH_HIGH	0xE11F
+#define HDC3020_R_STATUS		0xF32D
+
+#define HDC3020_THRESH_TEMP_MASK	GENMASK(8, 0)
+#define HDC3020_THRESH_TEMP_TRUNC_SHIFT	7
+#define HDC3020_THRESH_HUM_MASK		GENMASK(15, 9)
+#define HDC3020_THRESH_HUM_TRUNC_SHIFT	9
+
+#define HDC3020_STATUS_T_LOW_ALERT	BIT(6)
+#define HDC3020_STATUS_T_HIGH_ALERT	BIT(7)
+#define HDC3020_STATUS_RH_LOW_ALERT	BIT(8)
+#define HDC3020_STATUS_RH_HIGH_ALERT	BIT(9)
 
 #define HDC3020_READ_RETRY_TIMES	10
 #define HDC3020_BUSY_DELAY_MS		10
 
 #define HDC3020_CRC8_POLYNOMIAL		0x31
 
-static const u8 HDC3020_S_AUTO_10HZ_MOD0[2] = { 0x27, 0x37 };
-
-static const u8 HDC3020_EXIT_AUTO[2] = { 0x30, 0x93 };
-
-static const u8 HDC3020_R_T_RH_AUTO[2] = { 0xE0, 0x00 };
-static const u8 HDC3020_R_T_LOW_AUTO[2] = { 0xE0, 0x02 };
-static const u8 HDC3020_R_T_HIGH_AUTO[2] = { 0xE0, 0x03 };
-static const u8 HDC3020_R_RH_LOW_AUTO[2] = { 0xE0, 0x04 };
-static const u8 HDC3020_R_RH_HIGH_AUTO[2] = { 0xE0, 0x05 };
+#define HDC3020_MIN_TEMP		-40
+#define HDC3020_MAX_TEMP		125
 
 struct hdc3020_data {
 	struct i2c_client *client;
@@ -54,18 +79,37 @@ struct hdc3020_data {
 
 static const int hdc3020_heater_vals[] = {0, 1, 0x3FFF};
 
+static const struct iio_event_spec hdc3020_t_rh_event[] = {
+	{
+		.type = IIO_EV_TYPE_THRESH,
+		.dir = IIO_EV_DIR_RISING,
+		.mask_separate = BIT(IIO_EV_INFO_VALUE) |
+		BIT(IIO_EV_INFO_HYSTERESIS),
+	},
+	{
+		.type = IIO_EV_TYPE_THRESH,
+		.dir = IIO_EV_DIR_FALLING,
+		.mask_separate = BIT(IIO_EV_INFO_VALUE) |
+		BIT(IIO_EV_INFO_HYSTERESIS),
+	},
+};
+
 static const struct iio_chan_spec hdc3020_channels[] = {
 	{
 		.type = IIO_TEMP,
 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
 		BIT(IIO_CHAN_INFO_SCALE) | BIT(IIO_CHAN_INFO_PEAK) |
 		BIT(IIO_CHAN_INFO_TROUGH) | BIT(IIO_CHAN_INFO_OFFSET),
+		.event_spec = hdc3020_t_rh_event,
+		.num_event_specs = ARRAY_SIZE(hdc3020_t_rh_event),
 	},
 	{
 		.type = IIO_HUMIDITYRELATIVE,
 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
 		BIT(IIO_CHAN_INFO_SCALE) | BIT(IIO_CHAN_INFO_PEAK) |
 		BIT(IIO_CHAN_INFO_TROUGH),
+		.event_spec = hdc3020_t_rh_event,
+		.num_event_specs = ARRAY_SIZE(hdc3020_t_rh_event),
 	},
 	{
 		/*
@@ -82,7 +126,7 @@ static const struct iio_chan_spec hdc3020_channels[] = {
 
 DECLARE_CRC8_TABLE(hdc3020_crc8_table);
 
-static int hdc3020_write_bytes(struct hdc3020_data *data, const u8 *buf, u8 len)
+static int hdc3020_write_bytes(struct hdc3020_data *data, u8 *buf, u8 len)
 {
 	struct i2c_client *client = data->client;
 	struct i2c_msg msg;
@@ -90,7 +134,7 @@ static int hdc3020_write_bytes(struct hdc3020_data *data, const u8 *buf, u8 len)
 
 	msg.addr = client->addr;
 	msg.flags = 0;
-	msg.buf = (char *)buf;
+	msg.buf = buf;
 	msg.len = len;
 
 	/*
@@ -109,26 +153,28 @@ static int hdc3020_write_bytes(struct hdc3020_data *data, const u8 *buf, u8 len)
 	return -ETIMEDOUT;
 }
 
-static int hdc3020_read_bytes(struct hdc3020_data *data, const u8 *buf,
-			      void *val, int len)
+static
+int hdc3020_read_bytes(struct hdc3020_data *data, u16 reg, u8 *buf, int len)
 {
+	u8 reg_buf[2];
 	int ret, cnt;
 	struct i2c_client *client = data->client;
 	struct i2c_msg msg[2] = {
 		[0] = {
 			.addr = client->addr,
 			.flags = 0,
-			.buf = (char *)buf,
+			.buf = reg_buf,
 			.len = 2,
 		},
 		[1] = {
 			.addr = client->addr,
 			.flags = I2C_M_RD,
-			.buf = val,
+			.buf = buf,
 			.len = len,
 		},
 	};
 
+	put_unaligned_be16(reg, reg_buf);
 	/*
 	 * During the measurement process, HDC3020 will not return data.
 	 * So wait for a while and try again
@@ -145,48 +191,12 @@ static int hdc3020_read_bytes(struct hdc3020_data *data, const u8 *buf,
 	return -ETIMEDOUT;
 }
 
-static int hdc3020_read_measurement(struct hdc3020_data *data,
-				    enum iio_chan_type type, int *val)
-{
-	u8 crc, buf[6];
-	int ret;
-
-	ret = hdc3020_read_bytes(data, HDC3020_R_T_RH_AUTO, buf, 6);
-	if (ret < 0)
-		return ret;
-
-	/* CRC check of the temperature measurement */
-	crc = crc8(hdc3020_crc8_table, buf, 2, CRC8_INIT_VALUE);
-	if (crc != buf[2])
-		return -EINVAL;
-
-	/* CRC check of the relative humidity measurement */
-	crc = crc8(hdc3020_crc8_table, buf + 3, 2, CRC8_INIT_VALUE);
-	if (crc != buf[5])
-		return -EINVAL;
-
-	if (type == IIO_TEMP)
-		*val = get_unaligned_be16(buf);
-	else if (type == IIO_HUMIDITYRELATIVE)
-		*val = get_unaligned_be16(&buf[3]);
-	else
-		return -EINVAL;
-
-	return 0;
-}
-
-/*
- * After exiting the automatic measurement mode or resetting, the peak
- * value will be reset to the default value
- * This method is used to get the highest temp measured during automatic
- * measurement
- */
-static int hdc3020_read_high_peak_t(struct hdc3020_data *data, int *val)
+static int hdc3020_read_be16(struct hdc3020_data *data, u16 reg)
 {
 	u8 crc, buf[3];
 	int ret;
 
-	ret = hdc3020_read_bytes(data, HDC3020_R_T_HIGH_AUTO, buf, 3);
+	ret = hdc3020_read_bytes(data, reg, buf, 3);
 	if (ret < 0)
 		return ret;
 
@@ -194,73 +204,43 @@ static int hdc3020_read_high_peak_t(struct hdc3020_data *data, int *val)
 	if (crc != buf[2])
 		return -EINVAL;
 
-	*val = get_unaligned_be16(buf);
-
-	return 0;
+	return get_unaligned_be16(buf);
 }
 
-/*
- * This method is used to get the lowest temp measured during automatic
- * measurement
- */
-static int hdc3020_read_low_peak_t(struct hdc3020_data *data, int *val)
+static int hdc3020_exec_cmd(struct hdc3020_data *data, u16 reg)
 {
-	u8 crc, buf[3];
-	int ret;
+	u8 reg_buf[2];
 
-	ret = hdc3020_read_bytes(data, HDC3020_R_T_LOW_AUTO, buf, 3);
-	if (ret < 0)
-		return ret;
-
-	crc = crc8(hdc3020_crc8_table, buf, 2, CRC8_INIT_VALUE);
-	if (crc != buf[2])
-		return -EINVAL;
-
-	*val = get_unaligned_be16(buf);
-
-	return 0;
+	put_unaligned_be16(reg, reg_buf);
+	return hdc3020_write_bytes(data, reg_buf, 2);
 }
 
-/*
- * This method is used to get the highest humidity measured during automatic
- * measurement
- */
-static int hdc3020_read_high_peak_rh(struct hdc3020_data *data, int *val)
+static int hdc3020_read_measurement(struct hdc3020_data *data,
+				    enum iio_chan_type type, int *val)
 {
-	u8 crc, buf[3];
+	u8 crc, buf[6];
 	int ret;
 
-	ret = hdc3020_read_bytes(data, HDC3020_R_RH_HIGH_AUTO, buf, 3);
+	ret = hdc3020_read_bytes(data, HDC3020_R_T_RH_AUTO, buf, 6);
 	if (ret < 0)
 		return ret;
 
+	/* CRC check of the temperature measurement */
 	crc = crc8(hdc3020_crc8_table, buf, 2, CRC8_INIT_VALUE);
 	if (crc != buf[2])
 		return -EINVAL;
 
-	*val = get_unaligned_be16(buf);
-
-	return 0;
-}
-
-/*
- * This method is used to get the lowest humidity measured during automatic
- * measurement
- */
-static int hdc3020_read_low_peak_rh(struct hdc3020_data *data, int *val)
-{
-	u8 crc, buf[3];
-	int ret;
-
-	ret = hdc3020_read_bytes(data, HDC3020_R_RH_LOW_AUTO, buf, 3);
-	if (ret < 0)
-		return ret;
-
-	crc = crc8(hdc3020_crc8_table, buf, 2, CRC8_INIT_VALUE);
-	if (crc != buf[2])
+	/* CRC check of the relative humidity measurement */
+	crc = crc8(hdc3020_crc8_table, buf + 3, 2, CRC8_INIT_VALUE);
+	if (crc != buf[5])
 		return -EINVAL;
 
-	*val = get_unaligned_be16(buf);
+	if (type == IIO_TEMP)
+		*val = get_unaligned_be16(buf);
+	else if (type == IIO_HUMIDITYRELATIVE)
+		*val = get_unaligned_be16(&buf[3]);
+	else
+		return -EINVAL;
 
 	return 0;
 }
@@ -286,28 +266,28 @@ static int hdc3020_read_raw(struct iio_dev *indio_dev,
 	}
 	case IIO_CHAN_INFO_PEAK: {
 		guard(mutex)(&data->lock);
-		if (chan->type == IIO_TEMP) {
-			ret = hdc3020_read_high_peak_t(data, val);
-			if (ret < 0)
-				return ret;
-		} else {
-			ret = hdc3020_read_high_peak_rh(data, val);
-			if (ret < 0)
-				return ret;
-		}
+		if (chan->type == IIO_TEMP)
+			ret = hdc3020_read_be16(data, HDC3020_R_T_HIGH_AUTO);
+		else
+			ret = hdc3020_read_be16(data, HDC3020_R_RH_HIGH_AUTO);
+
+		if (ret < 0)
+			return ret;
+
+		*val = ret;
 		return IIO_VAL_INT;
 	}
 	case IIO_CHAN_INFO_TROUGH: {
 		guard(mutex)(&data->lock);
-		if (chan->type == IIO_TEMP) {
-			ret = hdc3020_read_low_peak_t(data, val);
-			if (ret < 0)
-				return ret;
-		} else {
-			ret = hdc3020_read_low_peak_rh(data, val);
-			if (ret < 0)
-				return ret;
-		}
+		if (chan->type == IIO_TEMP)
+			ret = hdc3020_read_be16(data, HDC3020_R_T_LOW_AUTO);
+		else
+			ret = hdc3020_read_be16(data, HDC3020_R_RH_LOW_AUTO);
+
+		if (ret < 0)
+			return ret;
+
+		*val = ret;
 		return IIO_VAL_INT;
 	}
 	case IIO_CHAN_INFO_SCALE:
@@ -352,23 +332,17 @@ static int hdc3020_update_heater(struct hdc3020_data *data, int val)
 	if (val < hdc3020_heater_vals[0] || val > hdc3020_heater_vals[2])
 		return -EINVAL;
 
-	buf[0] = HDC3020_HEATER_CMD_MSB;
+	if (!val)
+		hdc3020_exec_cmd(data, HDC3020_HEATER_DISABLE);
 
-	if (!val) {
-		buf[1] = HDC3020_HEATER_DISABLE;
-		return hdc3020_write_bytes(data, buf, 2);
-	}
-
-	buf[1] = HDC3020_HEATER_CONFIG;
+	put_unaligned_be16(HDC3020_HEATER_CONFIG, buf);
 	put_unaligned_be16(val & GENMASK(13, 0), &buf[2]);
 	buf[4] = crc8(hdc3020_crc8_table, buf + 2, 2, CRC8_INIT_VALUE);
 	ret = hdc3020_write_bytes(data, buf, 5);
 	if (ret < 0)
 		return ret;
 
-	buf[1] = HDC3020_HEATER_ENABLE;
-
-	return hdc3020_write_bytes(data, buf, 2);
+	return hdc3020_exec_cmd(data, HDC3020_HEATER_ENABLE);
 }
 
 static int hdc3020_write_raw(struct iio_dev *indio_dev,
@@ -389,15 +363,197 @@ static int hdc3020_write_raw(struct iio_dev *indio_dev,
 	return -EINVAL;
 }
 
+static int hdc3020_write_thresh(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 hdc3020_data *data = iio_priv(indio_dev);
+	u8 buf[5];
+	u64 tmp;
+	u16 reg;
+	int ret;
+
+	/* Supported temperature range is from –40 to 125 degree celsius */
+	if (val < HDC3020_MIN_TEMP || val > HDC3020_MAX_TEMP)
+		return -EINVAL;
+
+	/* Select threshold register */
+	if (info == IIO_EV_INFO_VALUE) {
+		if (dir == IIO_EV_DIR_RISING)
+			reg = HDC3020_S_T_RH_THRESH_HIGH;
+		else
+			reg = HDC3020_S_T_RH_THRESH_LOW;
+	} else {
+		if (dir == IIO_EV_DIR_RISING)
+			reg = HDC3020_S_T_RH_THRESH_HIGH_CLR;
+		else
+			reg = HDC3020_S_T_RH_THRESH_LOW_CLR;
+	}
+
+	guard(mutex)(&data->lock);
+	ret = hdc3020_read_be16(data, reg);
+	if (ret < 0)
+		return ret;
+
+	switch (chan->type) {
+	case IIO_TEMP:
+		/*
+		 * Calculate temperature threshold, shift it down to get the
+		 * truncated threshold representation in the 9LSBs while keeping
+		 * the current humidity threshold in the 7 MSBs.
+		 */
+		tmp = ((u64)(((val + 45) * MICRO) + val2)) * 65535ULL;
+		tmp = div_u64(tmp, MICRO * 175);
+		val = tmp >> HDC3020_THRESH_TEMP_TRUNC_SHIFT;
+		val = FIELD_PREP(HDC3020_THRESH_TEMP_MASK, val);
+		val |= (FIELD_GET(HDC3020_THRESH_HUM_MASK, ret) <<
+			HDC3020_THRESH_HUM_TRUNC_SHIFT);
+		break;
+	case IIO_HUMIDITYRELATIVE:
+		/*
+		 * Calculate humidity threshold, shift it down and up to get the
+		 * truncated threshold representation in the 7MSBs while keeping
+		 * the current temperature threshold in the 9 LSBs.
+		 */
+		tmp = ((u64)((val * MICRO) + val2)) * 65535ULL;
+		tmp = div_u64(tmp, MICRO * 100);
+		val = tmp >> HDC3020_THRESH_HUM_TRUNC_SHIFT;
+		val = FIELD_PREP(HDC3020_THRESH_HUM_MASK, val);
+		val |= FIELD_GET(HDC3020_THRESH_TEMP_MASK, ret);
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	put_unaligned_be16(reg, buf);
+	put_unaligned_be16(val, buf + 2);
+	buf[4] = crc8(hdc3020_crc8_table, buf + 2, 2, CRC8_INIT_VALUE);
+	return hdc3020_write_bytes(data, buf, 5);
+}
+
+static int hdc3020_read_thresh(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 hdc3020_data *data = iio_priv(indio_dev);
+	u16 reg;
+	int ret;
+
+	/* Select threshold register */
+	if (info == IIO_EV_INFO_VALUE) {
+		if (dir == IIO_EV_DIR_RISING)
+			reg = HDC3020_R_T_RH_THRESH_HIGH;
+		else
+			reg = HDC3020_R_T_RH_THRESH_LOW;
+	} else {
+		if (dir == IIO_EV_DIR_RISING)
+			reg = HDC3020_R_T_RH_THRESH_HIGH_CLR;
+		else
+			reg = HDC3020_R_T_RH_THRESH_LOW_CLR;
+	}
+
+	guard(mutex)(&data->lock);
+	ret = hdc3020_read_be16(data, reg);
+	if (ret < 0)
+		return ret;
+
+	switch (chan->type) {
+	case IIO_TEMP:
+		/*
+		 * Get the temperature threshold from 9 LSBs, shift them to get
+		 * the truncated temperature threshold representation and
+		 * calculate the threshold according to the formula in the
+		 * datasheet.
+		 */
+		*val = FIELD_GET(HDC3020_THRESH_TEMP_MASK, ret);
+		*val = *val << HDC3020_THRESH_TEMP_TRUNC_SHIFT;
+		*val = -2949075 + (175 * (*val));
+		*val2 = 65535;
+		return IIO_VAL_FRACTIONAL;
+	case IIO_HUMIDITYRELATIVE:
+		/*
+		 * Get the humidity threshold from 7 MSBs, shift them to get the
+		 * truncated humidity threshold representation and calculate the
+		 * threshold according to the formula in the datasheet.
+		 */
+		*val = FIELD_GET(HDC3020_THRESH_HUM_MASK, ret);
+		*val = (*val << HDC3020_THRESH_HUM_TRUNC_SHIFT) * 100;
+		*val2 = 65535;
+		return IIO_VAL_FRACTIONAL;
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static irqreturn_t hdc3020_interrupt_handler(int irq, void *private)
+{
+	struct iio_dev *indio_dev = private;
+	struct hdc3020_data *data;
+	s64 time;
+	int ret;
+
+	data = iio_priv(indio_dev);
+	ret = hdc3020_read_be16(data, HDC3020_R_STATUS);
+	if (ret < 0)
+		return IRQ_HANDLED;
+
+	if (!(ret & (HDC3020_STATUS_T_HIGH_ALERT | HDC3020_STATUS_T_LOW_ALERT |
+		HDC3020_STATUS_RH_HIGH_ALERT | HDC3020_STATUS_RH_LOW_ALERT)))
+		return IRQ_NONE;
+
+	time = iio_get_time_ns(indio_dev);
+	if (ret & HDC3020_STATUS_T_HIGH_ALERT)
+		iio_push_event(indio_dev,
+			       IIO_MOD_EVENT_CODE(IIO_TEMP, 0,
+						  IIO_NO_MOD,
+						  IIO_EV_TYPE_THRESH,
+						  IIO_EV_DIR_RISING),
+						  time);
+
+	if (ret & HDC3020_STATUS_T_LOW_ALERT)
+		iio_push_event(indio_dev,
+			       IIO_MOD_EVENT_CODE(IIO_TEMP, 0,
+						  IIO_NO_MOD,
+						  IIO_EV_TYPE_THRESH,
+						  IIO_EV_DIR_FALLING),
+						  time);
+
+	if (ret & HDC3020_STATUS_RH_HIGH_ALERT)
+		iio_push_event(indio_dev,
+			       IIO_MOD_EVENT_CODE(IIO_HUMIDITYRELATIVE, 0,
+						  IIO_NO_MOD,
+						  IIO_EV_TYPE_THRESH,
+						  IIO_EV_DIR_RISING),
+						  time);
+
+	if (ret & HDC3020_STATUS_RH_LOW_ALERT)
+		iio_push_event(indio_dev,
+			       IIO_MOD_EVENT_CODE(IIO_HUMIDITYRELATIVE, 0,
+						  IIO_NO_MOD,
+						  IIO_EV_TYPE_THRESH,
+						  IIO_EV_DIR_FALLING),
+						  time);
+
+	return IRQ_HANDLED;
+}
+
 static const struct iio_info hdc3020_info = {
 	.read_raw = hdc3020_read_raw,
 	.write_raw = hdc3020_write_raw,
 	.read_avail = hdc3020_read_available,
+	.read_event_value = hdc3020_read_thresh,
+	.write_event_value = hdc3020_write_thresh,
 };
 
 static void hdc3020_stop(void *data)
 {
-	hdc3020_write_bytes((struct hdc3020_data *)data, HDC3020_EXIT_AUTO, 2);
+	hdc3020_exec_cmd((struct hdc3020_data *)data, HDC3020_EXIT_AUTO);
 }
 
 static int hdc3020_probe(struct i2c_client *client)
@@ -424,8 +580,25 @@ static int hdc3020_probe(struct i2c_client *client)
 	indio_dev->info = &hdc3020_info;
 	indio_dev->channels = hdc3020_channels;
 	indio_dev->num_channels = ARRAY_SIZE(hdc3020_channels);
+	if (client->irq) {
+		ret = devm_request_threaded_irq(&client->dev, client->irq,
+						NULL, hdc3020_interrupt_handler,
+						IRQF_ONESHOT, "hdc3020",
+						indio_dev);
+		if (ret)
+			return dev_err_probe(&client->dev, ret,
+					     "Failed to request IRQ\n");
+
+		/*
+		 * The alert output is activated by default upon power up,
+		 * hardware reset, and soft reset. Clear the status register.
+		 */
+		ret = hdc3020_exec_cmd(data, HDC3020_S_STATUS);
+		if (ret)
+			return ret;
+	}
 
-	ret = hdc3020_write_bytes(data, HDC3020_S_AUTO_10HZ_MOD0, 2);
+	ret = hdc3020_exec_cmd(data, HDC3020_S_AUTO_10HZ_MOD0);
 	if (ret)
 		return dev_err_probe(&client->dev, ret,
 				     "Unable to set up measurement\n");
diff --git a/drivers/iio/humidity/hts221_i2c.c b/drivers/iio/humidity/hts221_i2c.c
index 30f2068ea156..5cb263e0ef5a 100644
--- a/drivers/iio/humidity/hts221_i2c.c
+++ b/drivers/iio/humidity/hts221_i2c.c
@@ -9,7 +9,7 @@
 
 #include <linux/kernel.h>
 #include <linux/module.h>
-#include <linux/acpi.h>
+#include <linux/mod_devicetable.h>
 #include <linux/i2c.h>
 #include <linux/slab.h>
 #include <linux/regmap.h>
@@ -63,7 +63,7 @@ static struct i2c_driver hts221_driver = {
 		.name = "hts221_i2c",
 		.pm = pm_sleep_ptr(&hts221_pm_ops),
 		.of_match_table = hts221_i2c_of_match,
-		.acpi_match_table = ACPI_PTR(hts221_acpi_match),
+		.acpi_match_table = hts221_acpi_match,
 	},
 	.probe = hts221_i2c_probe,
 	.id_table = hts221_i2c_id_table,