[PATCH v4 0/3] iio: mpl3115: support for events

[PATCH v4 0/3] iio: mpl3115: support for events

[Antoni Pokusinski]

Hello,
The mpl3115 device can raise interrupts when a pressure or temperature
threshold is crossed, this patchset adds support for them using IIO's
events interface.

In v4 mostly some minor variable rename changes and a comment in
read_info_raw according to the review in v3.

Kind regards,
Antoni Pokusinski

---
Changes since v3:
(patch 1/3 "use get_unaligned_be24() to retrieve pressure data")
* commit msg: "get_unaligned_be24" -> "get_unaligned_be24()"
* read_info_raw: renamed "tmp[3]" -> "press_be24[3]"
* read_info_raw: added comment at pressure val computation
(patch 2/3 "add threshold support")
* interrupt_handler: added sizeof() in a i2c_read_i2c_block call
* read_thresh: renamed "tmp" -> "press_tgt"
* write_thresh: renamed "tmp" -> "press_tgt"

Changes since v2:
(general)
* added the patch tidying up the pressure data retrieval (u8[3] used)
(patch 2/3 "add threshold support")
* includes: removed unused linux/units.h
* read_thresh: fixed comment formatting
* interrupt_handler: val_press is now u8[3] instead of __be32

Changes since v1:
(general)
* squashed the cleanup patch
* added the patch with the documentation update
(patch 1/2 "add threshold event support")
* patch description: explained changes in locking
* read_event_config: replaced switch with ifs
* read_event_config: return as early as possible, got rid of int_en_mask
* read/write_thresh: pressure: calculation changes to comply with raw ABI
* interrupt_handler: reordered the INT_SRC_* bits in if condition
* read/write_thresh: used sizeof() and values from limits.h
* write_thresh: replaced `u8 tmp[2]` with `__be16 tmp`
* dropped the space between casting `(u8 *) &tmp`


Antoni Pokusinski (3):
  iio: mpl3115: use get_unaligned_be24() to retrieve pressure data
  iio: mpl3115: add threshold events support
  iio: ABI: document pressure event attributes

 Documentation/ABI/testing/sysfs-bus-iio |   2 +
 drivers/iio/pressure/mpl3115.c          | 234 ++++++++++++++++++++++--
 2 files changed, 223 insertions(+), 13 deletions(-)


base-commit: 1d09cf18cc91d29f650ad9811ed4868d9304d6c7
-- 
2.25.1

[PATCH v4 1/3] iio: mpl3115: use get_unaligned_be24() to retrieve pressure data

[Antoni Pokusinski]

The pressure measurement result is arranged as 20-bit unsigned value
residing in three 8-bit registers. Hence, it can be retrieved using
get_unaligned_be24() and by applying 4-bit shift.

Reviewed-by: Marcelo Schmitt <marcelo.schmitt1@gmail.com>
Signed-off-by: Antoni Pokusinski <apokusinski01@gmail.com>
---
 drivers/iio/pressure/mpl3115.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/drivers/iio/pressure/mpl3115.c b/drivers/iio/pressure/mpl3115.c
index c212dfdf59ff..5594256fffbd 100644
--- a/drivers/iio/pressure/mpl3115.c
+++ b/drivers/iio/pressure/mpl3115.c
@@ -16,6 +16,7 @@
 #include <linux/i2c.h>
 #include <linux/module.h>
 #include <linux/property.h>
+#include <linux/unaligned.h>
 
 #include <linux/iio/buffer.h>
 #include <linux/iio/iio.h>
@@ -125,7 +126,7 @@ static int mpl3115_read_info_raw(struct mpl3115_data *data,
 
 	switch (chan->type) {
 	case IIO_PRESSURE: { /* in 0.25 pascal / LSB */
-		__be32 tmp = 0;
+		u8 press_be24[3];
 
 		guard(mutex)(&data->lock);
 		ret = mpl3115_request(data);
@@ -134,11 +135,17 @@ static int mpl3115_read_info_raw(struct mpl3115_data *data,
 
 		ret = i2c_smbus_read_i2c_block_data(data->client,
 						    MPL3115_OUT_PRESS,
-						    3, (u8 *) &tmp);
+						    sizeof(press_be24),
+						    press_be24);
 		if (ret < 0)
 			return ret;
 
-		*val = be32_to_cpu(tmp) >> chan->scan_type.shift;
+		/*
+		 * The pressure channel shift is applied in the case where the
+		 * data (24-bit big endian) is read into a 32-bit buffer. Here
+		 * the data is stored in a 24-bit buffer, so the shift is 4.
+		 */
+		*val = get_unaligned_be24(press_be24) >> 4;
 		return IIO_VAL_INT;
 	}
 	case IIO_TEMP: { /* in 0.0625 celsius / LSB */
-- 
2.25.1

[PATCH v4 2/3] iio: mpl3115: add threshold events support

[Antoni Pokusinski]

Add support for pressure and temperature rising threshold events. For
both channels *_en and *_value (in raw units) attributes are exposed.

Since in write_event_config() the ctrl_reg1.active and ctrl_reg4
are modified, accessing the data->ctrl_reg{1,4} in set_trigger_state()
and write_event_config() needs to be now guarded by data->lock.
Otherwise, it would be possible that 2 concurrent threads executing
these functions would access the data->ctrl_reg{1,4} at the same time
and then one would overwrite the other's result.

Signed-off-by: Antoni Pokusinski <apokusinski01@gmail.com>
---
 drivers/iio/pressure/mpl3115.c | 221 +++++++++++++++++++++++++++++++--
 1 file changed, 211 insertions(+), 10 deletions(-)

diff --git a/drivers/iio/pressure/mpl3115.c b/drivers/iio/pressure/mpl3115.c
index 5594256fffbd..aeac1586f12e 100644
--- a/drivers/iio/pressure/mpl3115.c
+++ b/drivers/iio/pressure/mpl3115.c
@@ -14,11 +14,13 @@
 #include <linux/cleanup.h>
 #include <linux/delay.h>
 #include <linux/i2c.h>
+#include <linux/limits.h>
 #include <linux/module.h>
 #include <linux/property.h>
 #include <linux/unaligned.h>
 
 #include <linux/iio/buffer.h>
+#include <linux/iio/events.h>
 #include <linux/iio/iio.h>
 #include <linux/iio/sysfs.h>
 #include <linux/iio/triggered_buffer.h>
@@ -31,6 +33,8 @@
 #define MPL3115_WHO_AM_I 0x0c
 #define MPL3115_INT_SOURCE 0x12
 #define MPL3115_PT_DATA_CFG 0x13
+#define MPL3115_PRESS_TGT 0x16 /* MSB first, 16 bit */
+#define MPL3115_TEMP_TGT 0x18
 #define MPL3115_CTRL_REG1 0x26
 #define MPL3115_CTRL_REG2 0x27
 #define MPL3115_CTRL_REG3 0x28
@@ -43,6 +47,8 @@
 #define MPL3115_STATUS_TEMP_RDY BIT(1)
 
 #define MPL3115_INT_SRC_DRDY BIT(7)
+#define MPL3115_INT_SRC_PTH BIT(3)
+#define MPL3115_INT_SRC_TTH BIT(2)
 
 #define MPL3115_PT_DATA_EVENT_ALL GENMASK(2, 0)
 
@@ -57,6 +63,8 @@
 #define MPL3115_CTRL3_IPOL2 BIT(1)
 
 #define MPL3115_CTRL4_INT_EN_DRDY BIT(7)
+#define MPL3115_CTRL4_INT_EN_PTH BIT(3)
+#define MPL3115_CTRL4_INT_EN_TTH BIT(2)
 
 #define MPL3115_CTRL5_INT_CFG_DRDY BIT(7)
 
@@ -84,6 +92,7 @@ struct mpl3115_data {
 	struct iio_trigger *drdy_trig;
 	struct mutex lock;
 	u8 ctrl_reg1;
+	u8 ctrl_reg4;
 };
 
 enum mpl3115_irq_pin {
@@ -313,6 +322,15 @@ static irqreturn_t mpl3115_trigger_handler(int irq, void *p)
 	return IRQ_HANDLED;
 }
 
+static const struct iio_event_spec mpl3115_temp_press_event[] = {
+	{
+		.type = IIO_EV_TYPE_THRESH,
+		.dir = IIO_EV_DIR_RISING,
+		.mask_separate = BIT(IIO_EV_INFO_ENABLE) |
+				 BIT(IIO_EV_INFO_VALUE),
+	},
+};
+
 static const struct iio_chan_spec mpl3115_channels[] = {
 	{
 		.type = IIO_PRESSURE,
@@ -328,7 +346,9 @@ static const struct iio_chan_spec mpl3115_channels[] = {
 			.storagebits = 32,
 			.shift = 12,
 			.endianness = IIO_BE,
-		}
+		},
+		.event_spec = mpl3115_temp_press_event,
+		.num_event_specs = ARRAY_SIZE(mpl3115_temp_press_event),
 	},
 	{
 		.type = IIO_TEMP,
@@ -344,7 +364,9 @@ static const struct iio_chan_spec mpl3115_channels[] = {
 			.storagebits = 16,
 			.shift = 4,
 			.endianness = IIO_BE,
-		}
+		},
+		.event_spec = mpl3115_temp_press_event,
+		.num_event_specs = ARRAY_SIZE(mpl3115_temp_press_event),
 	},
 	IIO_CHAN_SOFT_TIMESTAMP(2),
 };
@@ -354,15 +376,46 @@ static irqreturn_t mpl3115_interrupt_handler(int irq, void *private)
 	struct iio_dev *indio_dev = private;
 	struct mpl3115_data *data = iio_priv(indio_dev);
 	int ret;
+	u8 val_press[3];
+	__be16 val_temp;
 
 	ret = i2c_smbus_read_byte_data(data->client, MPL3115_INT_SOURCE);
 	if (ret < 0)
 		return IRQ_HANDLED;
 
-	if (!(ret & MPL3115_INT_SRC_DRDY))
+	if (!(ret & (MPL3115_INT_SRC_TTH | MPL3115_INT_SRC_PTH |
+		     MPL3115_INT_SRC_DRDY)))
 		return IRQ_NONE;
 
-	iio_trigger_poll_nested(data->drdy_trig);
+	if (ret & MPL3115_INT_SRC_DRDY)
+		iio_trigger_poll_nested(data->drdy_trig);
+
+	if (ret & MPL3115_INT_SRC_PTH) {
+		iio_push_event(indio_dev,
+			       IIO_UNMOD_EVENT_CODE(IIO_PRESSURE, 0,
+						    IIO_EV_TYPE_THRESH,
+						    IIO_EV_DIR_RISING),
+						    iio_get_time_ns(indio_dev));
+
+		/* Reset the SRC_PTH bit in INT_SOURCE */
+		i2c_smbus_read_i2c_block_data(data->client,
+					      MPL3115_OUT_PRESS,
+					      sizeof(val_press), val_press);
+	}
+
+	if (ret & MPL3115_INT_SRC_TTH) {
+		iio_push_event(indio_dev,
+			       IIO_UNMOD_EVENT_CODE(IIO_TEMP, 0,
+						    IIO_EV_TYPE_THRESH,
+						    IIO_EV_DIR_RISING),
+						    iio_get_time_ns(indio_dev));
+
+		/* Reset the SRC_TTH bit in INT_SOURCE */
+		i2c_smbus_read_i2c_block_data(data->client,
+					      MPL3115_OUT_TEMP,
+					      sizeof(val_temp),
+					      (u8 *)&val_temp);
+	}
 
 	return IRQ_HANDLED;
 }
@@ -383,6 +436,7 @@ static int mpl3115_config_interrupt(struct mpl3115_data *data,
 		goto reg1_cleanup;
 
 	data->ctrl_reg1 = ctrl_reg1;
+	data->ctrl_reg4 = ctrl_reg4;
 
 	return 0;
 
@@ -396,15 +450,22 @@ static int mpl3115_set_trigger_state(struct iio_trigger *trig, bool state)
 {
 	struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
 	struct mpl3115_data *data = iio_priv(indio_dev);
-	u8 ctrl_reg1 = data->ctrl_reg1;
-	u8 ctrl_reg4 = state ? MPL3115_CTRL4_INT_EN_DRDY : 0;
+	u8 ctrl_reg1, ctrl_reg4;
 
-	if (state)
+	guard(mutex)(&data->lock);
+
+	ctrl_reg1 = data->ctrl_reg1;
+	ctrl_reg4 = data->ctrl_reg4;
+
+	if (state) {
 		ctrl_reg1 |= MPL3115_CTRL1_ACTIVE;
-	else
-		ctrl_reg1 &= ~MPL3115_CTRL1_ACTIVE;
+		ctrl_reg4 |= MPL3115_CTRL4_INT_EN_DRDY;
+	} else {
+		ctrl_reg4 &= ~MPL3115_CTRL4_INT_EN_DRDY;
 
-	guard(mutex)(&data->lock);
+		if (!ctrl_reg4)
+			ctrl_reg1 &= ~MPL3115_CTRL1_ACTIVE;
+	}
 
 	return mpl3115_config_interrupt(data, ctrl_reg1, ctrl_reg4);
 }
@@ -413,10 +474,150 @@ static const struct iio_trigger_ops mpl3115_trigger_ops = {
 	.set_trigger_state = mpl3115_set_trigger_state,
 };
 
+static int mpl3115_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 mpl3115_data *data = iio_priv(indio_dev);
+
+	if (chan->type == IIO_PRESSURE)
+		return !!(data->ctrl_reg4 & MPL3115_CTRL4_INT_EN_PTH);
+
+	if (chan->type == IIO_TEMP)
+		return !!(data->ctrl_reg4 & MPL3115_CTRL4_INT_EN_TTH);
+
+	return -EINVAL;
+}
+
+static int mpl3115_write_event_config(struct iio_dev *indio_dev,
+				      const struct iio_chan_spec *chan,
+				      enum iio_event_type type,
+				      enum iio_event_direction dir,
+				      bool state)
+{
+	struct mpl3115_data *data = iio_priv(indio_dev);
+	u8 int_en_mask;
+	u8 ctrl_reg1, ctrl_reg4;
+
+	switch (chan->type) {
+	case IIO_PRESSURE:
+		int_en_mask = MPL3115_CTRL4_INT_EN_PTH;
+		break;
+	case IIO_TEMP:
+		int_en_mask = MPL3115_CTRL4_INT_EN_TTH;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	guard(mutex)(&data->lock);
+
+	ctrl_reg1 = data->ctrl_reg1;
+	ctrl_reg4 = data->ctrl_reg4;
+
+	if (state) {
+		ctrl_reg1 |= MPL3115_CTRL1_ACTIVE;
+		ctrl_reg4 |= int_en_mask;
+	} else {
+		ctrl_reg4 &= ~int_en_mask;
+
+		if (!ctrl_reg4)
+			ctrl_reg1 &= ~MPL3115_CTRL1_ACTIVE;
+	}
+
+	return mpl3115_config_interrupt(data, ctrl_reg1, ctrl_reg4);
+}
+
+static int mpl3115_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 mpl3115_data *data = iio_priv(indio_dev);
+	int ret;
+	__be16 press_tgt;
+
+	if (info != IIO_EV_INFO_VALUE)
+		return -EINVAL;
+
+	switch (chan->type) {
+	case IIO_PRESSURE:
+		ret = i2c_smbus_read_i2c_block_data(data->client,
+						    MPL3115_PRESS_TGT,
+						    sizeof(press_tgt),
+						    (u8 *)&press_tgt);
+		if (ret < 0)
+			return ret;
+
+		/*
+		 * Target value for the pressure is 16-bit unsigned value,
+		 * expressed in 2 Pa units
+		 */
+		*val = be16_to_cpu(press_tgt) << 1;
+
+		return IIO_VAL_INT;
+	case IIO_TEMP:
+		ret = i2c_smbus_read_byte_data(data->client, MPL3115_TEMP_TGT);
+		if (ret < 0)
+			return ret;
+
+		/* Target value for the temperature is 8-bit 2's complement */
+		*val = sign_extend32(ret, 7);
+
+		return IIO_VAL_INT;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int mpl3115_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 mpl3115_data *data = iio_priv(indio_dev);
+	__be16 press_tgt;
+
+	if (info != IIO_EV_INFO_VALUE)
+		return -EINVAL;
+
+	switch (chan->type) {
+	case IIO_PRESSURE:
+		val >>= 1;
+
+		if (val < 0 || val > U16_MAX)
+			return -EINVAL;
+
+		press_tgt = cpu_to_be16(val);
+
+		return i2c_smbus_write_i2c_block_data(data->client,
+						      MPL3115_PRESS_TGT,
+						      sizeof(press_tgt),
+						      (u8 *)&press_tgt);
+	case IIO_TEMP:
+		if (val < S8_MIN || val > S8_MAX)
+			return -EINVAL;
+
+		return i2c_smbus_write_byte_data(data->client,
+						 MPL3115_TEMP_TGT, val);
+	default:
+		return -EINVAL;
+	}
+}
+
 static const struct iio_info mpl3115_info = {
 	.read_raw = &mpl3115_read_raw,
 	.read_avail = &mpl3115_read_avail,
 	.write_raw = &mpl3115_write_raw,
+	.read_event_config = mpl3115_read_event_config,
+	.write_event_config = mpl3115_write_event_config,
+	.read_event_value = mpl3115_read_thresh,
+	.write_event_value = mpl3115_write_thresh,
 };
 
 static int mpl3115_trigger_probe(struct mpl3115_data *data,
-- 
2.25.1

[PATCH v4 3/3] iio: ABI: document pressure event attributes

[Antoni Pokusinski]

Add sysfs pressure event attributes exposed by the mpl3115 driver. These
allow controlling the threshold value and the enable state.

Reviewed-by: Marcelo Schmitt <marcelo.schmitt1@gmail.com>
Signed-off-by: Antoni Pokusinski <apokusinski01@gmail.com>
---
 Documentation/ABI/testing/sysfs-bus-iio | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-bus-iio b/Documentation/ABI/testing/sysfs-bus-iio
index 352ab7b8476c..5f87dcee78f7 100644
--- a/Documentation/ABI/testing/sysfs-bus-iio
+++ b/Documentation/ABI/testing/sysfs-bus-iio
@@ -898,6 +898,7 @@ What:		/sys/.../iio:deviceX/events/in_tempY_thresh_rising_en
 What:		/sys/.../iio:deviceX/events/in_tempY_thresh_falling_en
 What:		/sys/.../iio:deviceX/events/in_capacitanceY_thresh_rising_en
 What:		/sys/.../iio:deviceX/events/in_capacitanceY_thresh_falling_en
+What:		/sys/.../iio:deviceX/events/in_pressure_thresh_rising_en
 KernelVersion:	2.6.37
 Contact:	linux-iio@vger.kernel.org
 Description:
@@ -1047,6 +1048,7 @@ What:		/sys/.../events/in_capacitanceY_thresh_rising_value
 What:		/sys/.../events/in_capacitanceY_thresh_falling_value
 What:		/sys/.../events/in_capacitanceY_thresh_adaptive_rising_value
 What:		/sys/.../events/in_capacitanceY_thresh_falling_rising_value
+What:		/sys/.../events/in_pressure_thresh_rising_value
 KernelVersion:	2.6.37
 Contact:	linux-iio@vger.kernel.org
 Description:
-- 
2.25.1

Re: [PATCH v4 0/3] iio: mpl3115: support for events

[Jonathan Cameron]

On Wed, 12 Nov 2025 23:56:58 +0100
Antoni Pokusinski <apokusinski01@gmail.com> wrote:

> Hello,
> The mpl3115 device can raise interrupts when a pressure or temperature
> threshold is crossed, this patchset adds support for them using IIO's
> events interface.
> 
> In v4 mostly some minor variable rename changes and a comment in
> read_info_raw according to the review in v3.
Looks good to me, thanks.

Applied to the togreg branch of iio.git but initially pushed out as
testing to let the build bots poke at it and see if they can find
anything we missed.

Thanks,

Jonathan

> 
> Kind regards,
> Antoni Pokusinski
> 
> ---
> Changes since v3:
> (patch 1/3 "use get_unaligned_be24() to retrieve pressure data")
> * commit msg: "get_unaligned_be24" -> "get_unaligned_be24()"
> * read_info_raw: renamed "tmp[3]" -> "press_be24[3]"
> * read_info_raw: added comment at pressure val computation
> (patch 2/3 "add threshold support")
> * interrupt_handler: added sizeof() in a i2c_read_i2c_block call
> * read_thresh: renamed "tmp" -> "press_tgt"
> * write_thresh: renamed "tmp" -> "press_tgt"
> 
> Changes since v2:
> (general)
> * added the patch tidying up the pressure data retrieval (u8[3] used)
> (patch 2/3 "add threshold support")
> * includes: removed unused linux/units.h
> * read_thresh: fixed comment formatting
> * interrupt_handler: val_press is now u8[3] instead of __be32
> 
> Changes since v1:
> (general)
> * squashed the cleanup patch
> * added the patch with the documentation update
> (patch 1/2 "add threshold event support")
> * patch description: explained changes in locking
> * read_event_config: replaced switch with ifs
> * read_event_config: return as early as possible, got rid of int_en_mask
> * read/write_thresh: pressure: calculation changes to comply with raw ABI
> * interrupt_handler: reordered the INT_SRC_* bits in if condition
> * read/write_thresh: used sizeof() and values from limits.h
> * write_thresh: replaced `u8 tmp[2]` with `__be16 tmp`
> * dropped the space between casting `(u8 *) &tmp`
> 
> 
> Antoni Pokusinski (3):
>   iio: mpl3115: use get_unaligned_be24() to retrieve pressure data
>   iio: mpl3115: add threshold events support
>   iio: ABI: document pressure event attributes
> 
>  Documentation/ABI/testing/sysfs-bus-iio |   2 +
>  drivers/iio/pressure/mpl3115.c          | 234 ++++++++++++++++++++++--
>  2 files changed, 223 insertions(+), 13 deletions(-)
> 
> 
> base-commit: 1d09cf18cc91d29f650ad9811ed4868d9304d6c7