[PATCH v4 0/3] iio: humidity: hdc3020: add threshold events support

[PATCH v4 0/3] iio: humidity: hdc3020: add threshold events support

[Dimitri Fedrau]

Based on Fix:
a69eeaad093d "iio: humidity: hdc3020: fix temperature offset" in branch
fixes-togreg

Changes in V2:
  - Fix alphabetical order of includes(Christophe)
  - Fix typo: change varibale name "HDC3020_R_R_RH_THRESH_LOW_CLR" to
    HDC3020_R_T_RH_THRESH_LOW_CLR to match variable name pattern(Christophe)
  - Add constants HDC3020_MIN_TEMP and HDC3020_MAX_TEMP for min/max threshold
    inputs (Christophe)
  - Change HDC3020_MIN_TEMP to -40, as stated in the datasheet(Javier)

Changes in V3:
  - drop u8 register pairs and switch to 16bit defines(Jonathan)
  - create helper functions to avoid code duplication(Jonathan)
  - Add interrupt bindings in example
  - use the decimal part for setting thresholds(Javier)
  - use return in switch cases hdc3020_read_thresh(Jonathan)
  - fix interrupt handler:(Jonathan)
    - return IRQ_HANDLED when we get a read back failure
    - take the timestamp into a local variable
  - fix multiline comments(Jonathan)
  - use fixed value "hdc3020" instead of dev_id in probe
  - clear interrupt after registering the interrupt handler
  - remove interrupt polarity

Changes in V4:
  - fix commit message of patch "iio: humidity: hdc3020: switch to 16bit
    register defines". (Jonathan)
  - add missing include in bindings example. (Javier, Rob)
  - added copyright information

Dimitri Fedrau (3):
  iio: humidity: hdc3020: switch to 16bit register defines
  dt-bindings: iio: humidity: hdc3020: add interrupt bindings in example
  iio: humidity: hdc3020: add threshold events support

 .../bindings/iio/humidity/ti,hdc3020.yaml     |   3 +
 drivers/iio/humidity/hdc3020.c                | 445 ++++++++++++------
 2 files changed, 312 insertions(+), 136 deletions(-)

-- 
2.39.2

[PATCH v4 1/3] iio: humidity: hdc3020: switch to 16bit register defines

[Dimitri Fedrau]

Switch to 16bit register defines and drop the const u8 register pairs.
By doing so we change the parameter of functions for reading and writing
to the device. Additionally create helper functions that are aware of the
new register format and apply them wherever possible.

Signed-off-by: Dimitri Fedrau <dima.fedrau@gmail.com>
---
 drivers/iio/humidity/hdc3020.c | 200 +++++++++++----------------------
 1 file changed, 63 insertions(+), 137 deletions(-)

diff --git a/drivers/iio/humidity/hdc3020.c b/drivers/iio/humidity/hdc3020.c
index ed70415512f6..4ae4dd3187db 100644
--- a/drivers/iio/humidity/hdc3020.c
+++ b/drivers/iio/humidity/hdc3020.c
@@ -21,26 +21,22 @@
 
 #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_HEATER_DISABLE		0x3066
+#define HDC3020_HEATER_ENABLE		0x306D
+#define HDC3020_HEATER_CONFIG		0x306E
+#define HDC3020_EXIT_AUTO		0x3093
+#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_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 };
-
 struct hdc3020_data {
 	struct i2c_client *client;
 	/*
@@ -82,7 +78,7 @@ 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 +86,7 @@ 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 +105,28 @@ 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 +143,12 @@ 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 +156,43 @@ 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;
-
-	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);
+	u8 reg_buf[2];
 
-	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 +218,28 @@ 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 +284,17 @@ 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,
@@ -397,7 +323,7 @@ static const struct iio_info hdc3020_info = {
 
 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)
@@ -425,7 +351,7 @@ static int hdc3020_probe(struct i2c_client *client)
 	indio_dev->channels = hdc3020_channels;
 	indio_dev->num_channels = ARRAY_SIZE(hdc3020_channels);
 
-	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");
-- 
2.39.2

[PATCH v4 2/3] dt-bindings: iio: humidity: hdc3020: add interrupt bindings in example

[Dimitri Fedrau]

Add interrupt bindings in example.

Signed-off-by: Dimitri Fedrau <dima.fedrau@gmail.com>
---
 Documentation/devicetree/bindings/iio/humidity/ti,hdc3020.yaml | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/Documentation/devicetree/bindings/iio/humidity/ti,hdc3020.yaml b/Documentation/devicetree/bindings/iio/humidity/ti,hdc3020.yaml
index 7f6d0f9edc75..8b5dedd1a598 100644
--- a/Documentation/devicetree/bindings/iio/humidity/ti,hdc3020.yaml
+++ b/Documentation/devicetree/bindings/iio/humidity/ti,hdc3020.yaml
@@ -43,6 +43,7 @@ additionalProperties: false
 
 examples:
   - |
+    #include <dt-bindings/interrupt-controller/irq.h>
     i2c {
         #address-cells = <1>;
         #size-cells = <0>;
@@ -51,5 +52,7 @@ examples:
             compatible = "ti,hdc3021", "ti,hdc3020";
             reg = <0x47>;
             vdd-supply = <&vcc_3v3>;
+            interrupt-parent = <&gpio3>;
+            interrupts = <23 IRQ_TYPE_EDGE_RISING>;
         };
     };
-- 
2.39.2

[PATCH v4 3/3] iio: humidity: hdc3020: add threshold events support

[Dimitri Fedrau]

Add threshold events support for temperature and relative humidity. To
enable them the higher and lower threshold registers must be programmed
and the higher threshold must be greater then or equal to the lower
threshold. Otherwise the event is disabled. Invalid hysteresis values
are ignored by the device. There is no further configuration possible.

Tested by setting thresholds/hysteresis and turning the heater on/off.
Used iio_event_monitor in tools/iio to catch events while constantly
displaying temperature and humidity values.

Signed-off-by: Dimitri Fedrau <dima.fedrau@gmail.com>
---
 drivers/iio/humidity/hdc3020.c | 247 +++++++++++++++++++++++++++++++++
 1 file changed, 247 insertions(+)

diff --git a/drivers/iio/humidity/hdc3020.c b/drivers/iio/humidity/hdc3020.c
index 4ae4dd3187db..1e5d0d4797b1 100644
--- a/drivers/iio/humidity/hdc3020.c
+++ b/drivers/iio/humidity/hdc3020.c
@@ -5,38 +5,67 @@
  *
  * 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_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
 
+#define HDC3020_MIN_TEMP		-40
+#define HDC3020_MAX_TEMP		125
+
 struct hdc3020_data {
 	struct i2c_client *client;
 	/*
@@ -50,18 +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),
 	},
 	{
 		/*
@@ -315,10 +363,192 @@ 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)
@@ -350,6 +580,23 @@ 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_exec_cmd(data, HDC3020_S_AUTO_10HZ_MOD0);
 	if (ret)
-- 
2.39.2

Re: [PATCH v4 3/3] iio: humidity: hdc3020: add threshold events support

[Javier Carrasco]

On 14.02.24 09:53, Dimitri Fedrau wrote:
> Add threshold events support for temperature and relative humidity. To
> enable them the higher and lower threshold registers must be programmed
> and the higher threshold must be greater then or equal to the lower
> threshold. Otherwise the event is disabled. Invalid hysteresis values
> are ignored by the device. There is no further configuration possible.
> 
> Tested by setting thresholds/hysteresis and turning the heater on/off.
> Used iio_event_monitor in tools/iio to catch events while constantly
> displaying temperature and humidity values.
> 
> Signed-off-by: Dimitri Fedrau <dima.fedrau@gmail.com>
> ---

Hi Dimitri,

now that the decimal part is used, the resolution loss is within the
ranges mentioned in the datasheet.

For the records: the truncated values lead to alerts slightly lower than
the target alerts. Therefore, measured values below the "comfort zone"
defined by the user (but close to the low alert) will not trigger
events. The other way around is "more secure" because the target comfort
zone is guaranteed:

-------- High val -> event (as expected)

******** Target High Alert

-------- Meas -> **event** (still in target comfort zone)

######## Truncated High Alert

...

******** Target Low Alert

-------- Meas -> **no event** (out of target comfort zone)

######## Truncated Low Alert

-------- Meas -> event (as expected)

But as I said, the resolution loss is in the valid range anyway:

Tested-by: Javier Carrasco <javier.carrasco.cruz@gmail.com>

Thank you for adding this feature.

Best regards,
Javier Carrasco

Re: [PATCH v4 2/3] dt-bindings: iio: humidity: hdc3020: add interrupt bindings in example

[Rob Herring]

On Wed, 14 Feb 2024 09:53:44 +0100, Dimitri Fedrau wrote:
> Add interrupt bindings in example.
> 
> Signed-off-by: Dimitri Fedrau <dima.fedrau@gmail.com>
> ---
>  Documentation/devicetree/bindings/iio/humidity/ti,hdc3020.yaml | 3 +++
>  1 file changed, 3 insertions(+)
> 

Acked-by: Rob Herring <robh@kernel.org>

Re: [PATCH v4 0/3] iio: humidity: hdc3020: add threshold events support

[Jonathan Cameron]

On Wed, 14 Feb 2024 09:53:42 +0100
Dimitri Fedrau <dima.fedrau@gmail.com> wrote:

> Based on Fix:
> a69eeaad093d "iio: humidity: hdc3020: fix temperature offset" in branch
> fixes-togreg

This applies fine independent of that (they will meet each other upstream!)
so I'll take this via my tree now rather than waiting to get that dependency
after a pull request  / rebase.  It will also actually get built in next
where the missing Kconfig / Makefile fix is in place.

Applied to the togreg branch of iio.git. Normally I'd push it out as testing but
given I haven't yet queued anything up today and this won't get built
until it hits next I've pushed it out as togreg directly after a quick local
build test.

Thanks,

Jonathan

> 
> Changes in V2:
>   - Fix alphabetical order of includes(Christophe)
>   - Fix typo: change varibale name "HDC3020_R_R_RH_THRESH_LOW_CLR" to
>     HDC3020_R_T_RH_THRESH_LOW_CLR to match variable name pattern(Christophe)
>   - Add constants HDC3020_MIN_TEMP and HDC3020_MAX_TEMP for min/max threshold
>     inputs (Christophe)
>   - Change HDC3020_MIN_TEMP to -40, as stated in the datasheet(Javier)
> 
> Changes in V3:
>   - drop u8 register pairs and switch to 16bit defines(Jonathan)
>   - create helper functions to avoid code duplication(Jonathan)
>   - Add interrupt bindings in example
>   - use the decimal part for setting thresholds(Javier)
>   - use return in switch cases hdc3020_read_thresh(Jonathan)
>   - fix interrupt handler:(Jonathan)
>     - return IRQ_HANDLED when we get a read back failure
>     - take the timestamp into a local variable
>   - fix multiline comments(Jonathan)
>   - use fixed value "hdc3020" instead of dev_id in probe
>   - clear interrupt after registering the interrupt handler
>   - remove interrupt polarity
> 
> Changes in V4:
>   - fix commit message of patch "iio: humidity: hdc3020: switch to 16bit
>     register defines". (Jonathan)
>   - add missing include in bindings example. (Javier, Rob)
>   - added copyright information
> 
> Dimitri Fedrau (3):
>   iio: humidity: hdc3020: switch to 16bit register defines
>   dt-bindings: iio: humidity: hdc3020: add interrupt bindings in example
>   iio: humidity: hdc3020: add threshold events support
> 
>  .../bindings/iio/humidity/ti,hdc3020.yaml     |   3 +
>  drivers/iio/humidity/hdc3020.c                | 445 ++++++++++++------
>  2 files changed, 312 insertions(+), 136 deletions(-)
> 

Re: [PATCH v4 3/3] iio: humidity: hdc3020: add threshold events support

[Dimitri Fedrau]

Am Thu, Feb 15, 2024 at 12:18:41AM +0100 schrieb Javier Carrasco:
> On 14.02.24 09:53, Dimitri Fedrau wrote:
> > Add threshold events support for temperature and relative humidity. To
> > enable them the higher and lower threshold registers must be programmed
> > and the higher threshold must be greater then or equal to the lower
> > threshold. Otherwise the event is disabled. Invalid hysteresis values
> > are ignored by the device. There is no further configuration possible.
> > 
> > Tested by setting thresholds/hysteresis and turning the heater on/off.
> > Used iio_event_monitor in tools/iio to catch events while constantly
> > displaying temperature and humidity values.
> > 
> > Signed-off-by: Dimitri Fedrau <dima.fedrau@gmail.com>
> > ---
> 
> Hi Dimitri,
>
Hi Javier,

> now that the decimal part is used, the resolution loss is within the
> ranges mentioned in the datasheet.
> 
> For the records: the truncated values lead to alerts slightly lower than
> the target alerts. Therefore, measured values below the "comfort zone"
> defined by the user (but close to the low alert) will not trigger
> events. The other way around is "more secure" because the target comfort
> zone is guaranteed:
> 
> -------- High val -> event (as expected)
> 
> ******** Target High Alert
> 
> -------- Meas -> **event** (still in target comfort zone)
> 
> ######## Truncated High Alert
> 
> ...
> 
> ******** Target Low Alert
> 
> -------- Meas -> **no event** (out of target comfort zone)
> 
> ######## Truncated Low Alert
> 
> -------- Meas -> event (as expected)
> 
> But as I said, the resolution loss is in the valid range anyway:
> 
> Tested-by: Javier Carrasco <javier.carrasco.cruz@gmail.com>
> 
> Thank you for adding this feature.
>
thanks for testing.

Best regards,
Dimitri Fedrau

Re: [PATCH v4 0/3] iio: humidity: hdc3020: add threshold events support

[Dimitri Fedrau]

Am Fri, Feb 16, 2024 at 01:17:21PM +0000 schrieb Jonathan Cameron:
> On Wed, 14 Feb 2024 09:53:42 +0100
> Dimitri Fedrau <dima.fedrau@gmail.com> wrote:
> 
> > Based on Fix:
> > a69eeaad093d "iio: humidity: hdc3020: fix temperature offset" in branch
> > fixes-togreg
> 
> This applies fine independent of that (they will meet each other upstream!)
> so I'll take this via my tree now rather than waiting to get that dependency
> after a pull request  / rebase.  It will also actually get built in next
> where the missing Kconfig / Makefile fix is in place.
> 
> Applied to the togreg branch of iio.git. Normally I'd push it out as testing but
> given I haven't yet queued anything up today and this won't get built
> until it hits next I've pushed it out as togreg directly after a quick local
> build test.
>
Great, thanks for reviewing. :)

Best regards,
Dimitri Fedrau