[2/2] iio: st_sensors: support open drain mode

Message ID 1447445915-12704-1-git-send-email-linus.walleij@linaro.org
State New
Headers show

Commit Message

Linus Walleij Nov. 13, 2015, 8:18 p.m.
Some types of ST Sensors can be connected to the same IRQ line
as other peripherals using open drain. Add a device tree binding
and a sensor data property to flip the right bit in the interrupt
control register to enable open drain mode on the INT line.

If the line is set to be open drain, also tag on IRQF_SHARED
to the IRQ flags when requesting the interrupt, as the whole
point of using open drain interrupt lines is to share them with
more than one peripheral (wire-or).

Cc: devicetree@vger.kernel.org
Cc: Giuseppe Barba <giuseppe.barba@st.com>
Cc: Denis Ciocca <denis.ciocca@st.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

---
 Documentation/devicetree/bindings/iio/st-sensors.txt |  3 +++
 drivers/iio/accel/st_accel_core.c                    |  8 ++++++++
 drivers/iio/common/st_sensors/st_sensors_core.c      | 20 ++++++++++++++++++++
 drivers/iio/common/st_sensors/st_sensors_trigger.c   |  9 +++++++++
 drivers/iio/gyro/st_gyro_core.c                      | 12 ++++++++++++
 drivers/iio/pressure/st_pressure_core.c              |  8 ++++++++
 include/linux/iio/common/st_sensors.h                |  6 ++++++
 include/linux/platform_data/st_sensors_pdata.h       |  2 ++
 8 files changed, 68 insertions(+)

-- 
2.4.3

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Comments

Rob Herring Nov. 15, 2015, 2:20 a.m. | #1
On Fri, Nov 13, 2015 at 09:18:35PM +0100, Linus Walleij wrote:
> Some types of ST Sensors can be connected to the same IRQ line

> as other peripherals using open drain. Add a device tree binding

> and a sensor data property to flip the right bit in the interrupt

> control register to enable open drain mode on the INT line.

> 

> If the line is set to be open drain, also tag on IRQF_SHARED

> to the IRQ flags when requesting the interrupt, as the whole

> point of using open drain interrupt lines is to share them with

> more than one peripheral (wire-or).

> 

> Cc: devicetree@vger.kernel.org

> Cc: Giuseppe Barba <giuseppe.barba@st.com>

> Cc: Denis Ciocca <denis.ciocca@st.com>

> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

> ---

>  Documentation/devicetree/bindings/iio/st-sensors.txt |  3 +++


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


>  drivers/iio/accel/st_accel_core.c                    |  8 ++++++++

>  drivers/iio/common/st_sensors/st_sensors_core.c      | 20 ++++++++++++++++++++

>  drivers/iio/common/st_sensors/st_sensors_trigger.c   |  9 +++++++++

>  drivers/iio/gyro/st_gyro_core.c                      | 12 ++++++++++++

>  drivers/iio/pressure/st_pressure_core.c              |  8 ++++++++

>  include/linux/iio/common/st_sensors.h                |  6 ++++++

>  include/linux/platform_data/st_sensors_pdata.h       |  2 ++

>  8 files changed, 68 insertions(+)

> 

> diff --git a/Documentation/devicetree/bindings/iio/st-sensors.txt b/Documentation/devicetree/bindings/iio/st-sensors.txt

> index d3ccdb190c53..4ac20cb2ae8d 100644

> --- a/Documentation/devicetree/bindings/iio/st-sensors.txt

> +++ b/Documentation/devicetree/bindings/iio/st-sensors.txt

> @@ -16,6 +16,9 @@ Optional properties:

>  - st,drdy-int-pin: the pin on the package that will be used to signal

>    "data ready" (valid values: 1 or 2). This property is not configurable

>    on all sensors.

> +- st,int-pin-open-drain: the interrupt/data ready line will be configured

> +  as open drain, which is useful if several sensors share the same

> +  interrupt line.

>  

>  Sensors may also have applicable pin control settings, those use the

>  standard bindings from pinctrl/pinctrl-bindings.txt.

> diff --git a/drivers/iio/accel/st_accel_core.c b/drivers/iio/accel/st_accel_core.c

> index 1132224cbc10..888682b95693 100644

> --- a/drivers/iio/accel/st_accel_core.c

> +++ b/drivers/iio/accel/st_accel_core.c

> @@ -96,6 +96,8 @@

>  #define ST_ACCEL_2_DRDY_IRQ_INT2_MASK		0x10

>  #define ST_ACCEL_2_IHL_IRQ_ADDR			0x22

>  #define ST_ACCEL_2_IHL_IRQ_MASK			0x80

> +#define ST_ACCEL_2_OD_IRQ_ADDR			0x22

> +#define ST_ACCEL_2_OD_IRQ_MASK			0x40

>  #define ST_ACCEL_2_MULTIREAD_BIT		true

>  

>  /* CUSTOM VALUES FOR SENSOR 3 */

> @@ -177,6 +179,8 @@

>  #define ST_ACCEL_5_DRDY_IRQ_INT2_MASK		0x20

>  #define ST_ACCEL_5_IHL_IRQ_ADDR			0x22

>  #define ST_ACCEL_5_IHL_IRQ_MASK			0x80

> +#define ST_ACCEL_5_OD_IRQ_ADDR			0x22

> +#define ST_ACCEL_5_OD_IRQ_MASK			0x40

>  #define ST_ACCEL_5_IG1_EN_ADDR			0x21

>  #define ST_ACCEL_5_IG1_EN_MASK			0x08

>  #define ST_ACCEL_5_MULTIREAD_BIT		false

> @@ -366,6 +370,8 @@ static const struct st_sensor_settings st_accel_sensors_settings[] = {

>  			.mask_int2 = ST_ACCEL_2_DRDY_IRQ_INT2_MASK,

>  			.addr_ihl = ST_ACCEL_2_IHL_IRQ_ADDR,

>  			.mask_ihl = ST_ACCEL_2_IHL_IRQ_MASK,

> +			.addr_od = ST_ACCEL_2_OD_IRQ_ADDR,

> +			.mask_od = ST_ACCEL_2_OD_IRQ_MASK,

>  		},

>  		.multi_read_bit = ST_ACCEL_2_MULTIREAD_BIT,

>  		.bootime = 2,

> @@ -552,6 +558,8 @@ static const struct st_sensor_settings st_accel_sensors_settings[] = {

>  			.mask_int2 = ST_ACCEL_5_DRDY_IRQ_INT2_MASK,

>  			.addr_ihl = ST_ACCEL_5_IHL_IRQ_ADDR,

>  			.mask_ihl = ST_ACCEL_5_IHL_IRQ_MASK,

> +			.addr_od = ST_ACCEL_5_OD_IRQ_ADDR,

> +			.mask_od = ST_ACCEL_5_OD_IRQ_MASK,

>  		},

>  		.multi_read_bit = ST_ACCEL_5_MULTIREAD_BIT,

>  		.bootime = 2, /* guess */

> diff --git a/drivers/iio/common/st_sensors/st_sensors_core.c b/drivers/iio/common/st_sensors/st_sensors_core.c

> index ed6f54d5c932..bff469dd9583 100644

> --- a/drivers/iio/common/st_sensors/st_sensors_core.c

> +++ b/drivers/iio/common/st_sensors/st_sensors_core.c

> @@ -302,6 +302,14 @@ static int st_sensors_set_drdy_int_pin(struct iio_dev *indio_dev,

>  		return -EINVAL;

>  	}

>  

> +	if (pdata->open_drain) {

> +		if (!sdata->sensor_settings->drdy_irq.addr_od)

> +			dev_err(&indio_dev->dev,

> +				"open drain requested but unsupported.\n");

> +		else

> +			sdata->int_pin_open_drain = true;

> +	}

> +

>  	return 0;

>  }

>  

> @@ -322,6 +330,8 @@ static struct st_sensors_platform_data *st_sensors_of_probe(struct device *dev,

>  	else

>  		pdata->drdy_int_pin = defdata ? defdata->drdy_int_pin : 0;

>  

> +	pdata->open_drain = of_property_read_bool(np, "st,int-pin-open-drain");

> +

>  	return pdata;

>  }

>  #else

> @@ -375,6 +385,16 @@ int st_sensors_init_sensor(struct iio_dev *indio_dev,

>  			return err;

>  	}

>  

> +	if (sdata->int_pin_open_drain) {

> +		dev_info(&indio_dev->dev,

> +			 "set interrupt line to open drain mode\n");

> +		err = st_sensors_write_data_with_mask(indio_dev,

> +				sdata->sensor_settings->drdy_irq.addr_od,

> +				sdata->sensor_settings->drdy_irq.mask_od, 1);

> +		if (err < 0)

> +			return err;

> +	}

> +

>  	err = st_sensors_set_axis_enable(indio_dev, ST_SENSORS_ENABLE_ALL_AXIS);

>  

>  	return err;

> diff --git a/drivers/iio/common/st_sensors/st_sensors_trigger.c b/drivers/iio/common/st_sensors/st_sensors_trigger.c

> index cb53d14aca94..4283468fd502 100644

> --- a/drivers/iio/common/st_sensors/st_sensors_trigger.c

> +++ b/drivers/iio/common/st_sensors/st_sensors_trigger.c

> @@ -67,6 +67,15 @@ int st_sensors_allocate_trigger(struct iio_dev *indio_dev,

>  			"rising edge\n", irq_trig);

>  		irq_trig = IRQF_TRIGGER_RISING;

>  	}

> +

> +	/*

> +	 * If the interrupt pin is Open Drain, by definition this

> +	 * means that the interrupt line may be shared with other

> +	 * peripherals.

> +	 */

> +	if (sdata->int_pin_open_drain)

> +		irq_trig |= IRQF_SHARED;

> +

>  	err = request_any_context_irq(irq,

>  			iio_trigger_generic_data_rdy_poll,

>  			irq_trig,

> diff --git a/drivers/iio/gyro/st_gyro_core.c b/drivers/iio/gyro/st_gyro_core.c

> index 260bfe021904..d53622b0e430 100644

> --- a/drivers/iio/gyro/st_gyro_core.c

> +++ b/drivers/iio/gyro/st_gyro_core.c

> @@ -63,6 +63,8 @@

>  #define ST_GYRO_1_DRDY_IRQ_INT2_MASK		0x08

>  #define ST_GYRO_1_IHL_IRQ_ADDR			0x22

>  #define ST_GYRO_1_IHL_IRQ_MASK			0x20

> +#define ST_GYRO_1_OD_IRQ_ADDR			0x22

> +#define ST_GYRO_1_OD_IRQ_MASK			0x10

>  #define ST_GYRO_1_MULTIREAD_BIT			true

>  

>  /* CUSTOM VALUES FOR SENSOR 2 */

> @@ -89,6 +91,8 @@

>  #define ST_GYRO_2_DRDY_IRQ_INT2_MASK		0x08

>  #define ST_GYRO_2_IHL_IRQ_ADDR			0x22

>  #define ST_GYRO_2_IHL_IRQ_MASK			0x20

> +#define ST_GYRO_2_OD_IRQ_ADDR			0x22

> +#define ST_GYRO_2_OD_IRQ_MASK			0x10

>  #define ST_GYRO_2_MULTIREAD_BIT			true

>  

>  /* CUSTOM VALUES FOR SENSOR 3 */

> @@ -115,6 +119,8 @@

>  #define ST_GYRO_3_DRDY_IRQ_INT2_MASK		0x08

>  #define ST_GYRO_3_IHL_IRQ_ADDR			0x22

>  #define ST_GYRO_3_IHL_IRQ_MASK			0x20

> +#define ST_GYRO_3_OD_IRQ_ADDR			0x22

> +#define ST_GYRO_3_OD_IRQ_MASK			0x10

>  #define ST_GYRO_3_MULTIREAD_BIT			true

>  

>  

> @@ -193,6 +199,8 @@ static const struct st_sensor_settings st_gyro_sensors_settings[] = {

>  			.mask_int2 = ST_GYRO_1_DRDY_IRQ_INT2_MASK,

>  			.addr_ihl = ST_GYRO_1_IHL_IRQ_ADDR,

>  			.mask_ihl = ST_GYRO_1_IHL_IRQ_MASK,

> +			.addr_od = ST_GYRO_1_OD_IRQ_ADDR,

> +			.mask_od = ST_GYRO_1_OD_IRQ_MASK,

>  		},

>  		.multi_read_bit = ST_GYRO_1_MULTIREAD_BIT,

>  		.bootime = 2,

> @@ -258,6 +266,8 @@ static const struct st_sensor_settings st_gyro_sensors_settings[] = {

>  			.mask_int2 = ST_GYRO_2_DRDY_IRQ_INT2_MASK,

>  			.addr_ihl = ST_GYRO_2_IHL_IRQ_ADDR,

>  			.mask_ihl = ST_GYRO_2_IHL_IRQ_MASK,

> +			.addr_od = ST_GYRO_2_OD_IRQ_ADDR,

> +			.mask_od = ST_GYRO_2_OD_IRQ_MASK,

>  		},

>  		.multi_read_bit = ST_GYRO_2_MULTIREAD_BIT,

>  		.bootime = 2,

> @@ -319,6 +329,8 @@ static const struct st_sensor_settings st_gyro_sensors_settings[] = {

>  			.mask_int2 = ST_GYRO_3_DRDY_IRQ_INT2_MASK,

>  			.addr_ihl = ST_GYRO_3_IHL_IRQ_ADDR,

>  			.mask_ihl = ST_GYRO_3_IHL_IRQ_MASK,

> +			.addr_od = ST_GYRO_3_OD_IRQ_ADDR,

> +			.mask_od = ST_GYRO_3_OD_IRQ_MASK,

>  		},

>  		.multi_read_bit = ST_GYRO_3_MULTIREAD_BIT,

>  		.bootime = 2,

> diff --git a/drivers/iio/pressure/st_pressure_core.c b/drivers/iio/pressure/st_pressure_core.c

> index 172393ad34af..38186288f79c 100644

> --- a/drivers/iio/pressure/st_pressure_core.c

> +++ b/drivers/iio/pressure/st_pressure_core.c

> @@ -64,6 +64,8 @@

>  #define ST_PRESS_LPS331AP_DRDY_IRQ_INT2_MASK	0x20

>  #define ST_PRESS_LPS331AP_IHL_IRQ_ADDR		0x22

>  #define ST_PRESS_LPS331AP_IHL_IRQ_MASK		0x80

> +#define ST_PRESS_LPS331AP_OD_IRQ_ADDR		0x22

> +#define ST_PRESS_LPS331AP_OD_IRQ_MASK		0x40

>  #define ST_PRESS_LPS331AP_MULTIREAD_BIT		true

>  #define ST_PRESS_LPS331AP_TEMP_OFFSET		42500

>  

> @@ -104,6 +106,8 @@

>  #define ST_PRESS_LPS25H_DRDY_IRQ_INT2_MASK	0x10

>  #define ST_PRESS_LPS25H_IHL_IRQ_ADDR		0x22

>  #define ST_PRESS_LPS25H_IHL_IRQ_MASK		0x80

> +#define ST_PRESS_LPS25H_OD_IRQ_ADDR		0x22

> +#define ST_PRESS_LPS25H_OD_IRQ_MASK		0x40

>  #define ST_PRESS_LPS25H_MULTIREAD_BIT		true

>  #define ST_PRESS_LPS25H_TEMP_OFFSET		42500

>  #define ST_PRESS_LPS25H_OUT_XL_ADDR		0x28

> @@ -226,6 +230,8 @@ static const struct st_sensor_settings st_press_sensors_settings[] = {

>  			.mask_int2 = ST_PRESS_LPS331AP_DRDY_IRQ_INT2_MASK,

>  			.addr_ihl = ST_PRESS_LPS331AP_IHL_IRQ_ADDR,

>  			.mask_ihl = ST_PRESS_LPS331AP_IHL_IRQ_MASK,

> +			.addr_od = ST_PRESS_LPS331AP_OD_IRQ_ADDR,

> +			.mask_od = ST_PRESS_LPS331AP_OD_IRQ_MASK,

>  		},

>  		.multi_read_bit = ST_PRESS_LPS331AP_MULTIREAD_BIT,

>  		.bootime = 2,

> @@ -312,6 +318,8 @@ static const struct st_sensor_settings st_press_sensors_settings[] = {

>  			.mask_int2 = ST_PRESS_LPS25H_DRDY_IRQ_INT2_MASK,

>  			.addr_ihl = ST_PRESS_LPS25H_IHL_IRQ_ADDR,

>  			.mask_ihl = ST_PRESS_LPS25H_IHL_IRQ_MASK,

> +			.addr_od = ST_PRESS_LPS25H_OD_IRQ_ADDR,

> +			.mask_od = ST_PRESS_LPS25H_OD_IRQ_MASK,

>  		},

>  		.multi_read_bit = ST_PRESS_LPS25H_MULTIREAD_BIT,

>  		.bootime = 2,

> diff --git a/include/linux/iio/common/st_sensors.h b/include/linux/iio/common/st_sensors.h

> index 6670c3d25c58..8972101224d9 100644

> --- a/include/linux/iio/common/st_sensors.h

> +++ b/include/linux/iio/common/st_sensors.h

> @@ -121,6 +121,8 @@ struct st_sensor_bdu {

>   * @mask_int2: mask to enable/disable IRQ on INT2 pin.

>   * @addr_ihl: address to enable/disable active low on the INT lines.

>   * @mask_ihl: mask to enable/disable active low on the INT lines.

> + * @addr_od: address to enable/disable Open Drain on the INT lines.

> + * @mask_od: mask to enable/disable Open Drain on the INT lines.

>   * struct ig1 - represents the Interrupt Generator 1 of sensors.

>   * @en_addr: address of the enable ig1 register.

>   * @en_mask: mask to write the on/off value for enable.

> @@ -131,6 +133,8 @@ struct st_sensor_data_ready_irq {

>  	u8 mask_int2;

>  	u8 addr_ihl;

>  	u8 mask_ihl;

> +	u8 addr_od;

> +	u8 mask_od;

>  	struct {

>  		u8 en_addr;

>  		u8 en_mask;

> @@ -212,6 +216,7 @@ struct st_sensor_settings {

>   * @odr: Output data rate of the sensor [Hz].

>   * num_data_channels: Number of data channels used in buffer.

>   * @drdy_int_pin: Redirect DRDY on pin 1 (1) or pin 2 (2).

> + * @int_pin_open_drain: Set the interrupt/DRDY to open drain.

>   * @get_irq_data_ready: Function to get the IRQ used for data ready signal.

>   * @tf: Transfer function structure used by I/O operations.

>   * @tb: Transfer buffers and mutex used by I/O operations.

> @@ -233,6 +238,7 @@ struct st_sensor_data {

>  	unsigned int num_data_channels;

>  

>  	u8 drdy_int_pin;

> +	bool int_pin_open_drain;

>  

>  	unsigned int (*get_irq_data_ready) (struct iio_dev *indio_dev);

>  

> diff --git a/include/linux/platform_data/st_sensors_pdata.h b/include/linux/platform_data/st_sensors_pdata.h

> index 753839187ba0..79b0e4cdb814 100644

> --- a/include/linux/platform_data/st_sensors_pdata.h

> +++ b/include/linux/platform_data/st_sensors_pdata.h

> @@ -16,9 +16,11 @@

>   * @drdy_int_pin: Redirect DRDY on pin 1 (1) or pin 2 (2).

>   *	Available only for accelerometer and pressure sensors.

>   *	Accelerometer DRDY on LSM330 available only on pin 1 (see datasheet).

> + * @open_drain: set the interrupt line to be open drain if possible.

>   */

>  struct st_sensors_platform_data {

>  	u8 drdy_int_pin;

> +	bool open_drain;

>  };

>  

>  #endif /* ST_SENSORS_PDATA_H */

> -- 

> 2.4.3

> 

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Linus Walleij Nov. 16, 2015, 8:57 a.m. | #2
On Mon, Nov 16, 2015 at 7:15 AM, Denis Ciocca <denis.ciocca@st.com> wrote:

> I'm not convinced about this one. If we declare sensors output as open drain,

> interrupt can be shared (as you also say).

>

> So, the irq management function should first check source registers if

> interrupt is really generated by sensor or not.


Yeah I was not testing actually using two sensors at the time so far, only
setting this property in the device tree for two sensors so that it was
possible to share a line between two sensors, but I only use one at a
time, I didn't try to start generic_buffer on both similtaneously...

OK I'll see if we can get the trigger to return IRQ_HANDLED or
IRQ_NO_IRQ.

Yours,
Linus Walleij
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Linus Walleij Nov. 16, 2015, 9:15 a.m. | #3
On Mon, Nov 16, 2015 at 9:57 AM, Linus Walleij <linus.walleij@linaro.org> wrote:
> On Mon, Nov 16, 2015 at 7:15 AM, Denis Ciocca <denis.ciocca@st.com> wrote:

>

>> I'm not convinced about this one. If we declare sensors output as open drain,

>> interrupt can be shared (as you also say).

>>

>> So, the irq management function should first check source registers if

>> interrupt is really generated by sensor or not.

>

> Yeah I was not testing actually using two sensors at the time so far, only

> setting this property in the device tree for two sensors so that it was

> possible to share a line between two sensors, but I only use one at a

> time, I didn't try to start generic_buffer on both similtaneously...

>

> OK I'll see if we can get the trigger to return IRQ_HANDLED or

> IRQ_NO_IRQ.


Actually this ties into the IRQ request discussion: to read the status from
the sensor, we need to do some I2C traffic, and for that, we need to have
a threaded IRQ handler (today we don't have that, we just request a
fastpath IRQ using the request_threaded() function), leading back to the
other discussion about any_context_irq() and how we should just call
down to the trigger layer if we are running a real thread in the IRQ handler.

It's a can of worms :D

Yours,
Linus Walleij
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Patch

diff --git a/Documentation/devicetree/bindings/iio/st-sensors.txt b/Documentation/devicetree/bindings/iio/st-sensors.txt
index d3ccdb190c53..4ac20cb2ae8d 100644
--- a/Documentation/devicetree/bindings/iio/st-sensors.txt
+++ b/Documentation/devicetree/bindings/iio/st-sensors.txt
@@ -16,6 +16,9 @@  Optional properties:
 - st,drdy-int-pin: the pin on the package that will be used to signal
   "data ready" (valid values: 1 or 2). This property is not configurable
   on all sensors.
+- st,int-pin-open-drain: the interrupt/data ready line will be configured
+  as open drain, which is useful if several sensors share the same
+  interrupt line.
 
 Sensors may also have applicable pin control settings, those use the
 standard bindings from pinctrl/pinctrl-bindings.txt.
diff --git a/drivers/iio/accel/st_accel_core.c b/drivers/iio/accel/st_accel_core.c
index 1132224cbc10..888682b95693 100644
--- a/drivers/iio/accel/st_accel_core.c
+++ b/drivers/iio/accel/st_accel_core.c
@@ -96,6 +96,8 @@ 
 #define ST_ACCEL_2_DRDY_IRQ_INT2_MASK		0x10
 #define ST_ACCEL_2_IHL_IRQ_ADDR			0x22
 #define ST_ACCEL_2_IHL_IRQ_MASK			0x80
+#define ST_ACCEL_2_OD_IRQ_ADDR			0x22
+#define ST_ACCEL_2_OD_IRQ_MASK			0x40
 #define ST_ACCEL_2_MULTIREAD_BIT		true
 
 /* CUSTOM VALUES FOR SENSOR 3 */
@@ -177,6 +179,8 @@ 
 #define ST_ACCEL_5_DRDY_IRQ_INT2_MASK		0x20
 #define ST_ACCEL_5_IHL_IRQ_ADDR			0x22
 #define ST_ACCEL_5_IHL_IRQ_MASK			0x80
+#define ST_ACCEL_5_OD_IRQ_ADDR			0x22
+#define ST_ACCEL_5_OD_IRQ_MASK			0x40
 #define ST_ACCEL_5_IG1_EN_ADDR			0x21
 #define ST_ACCEL_5_IG1_EN_MASK			0x08
 #define ST_ACCEL_5_MULTIREAD_BIT		false
@@ -366,6 +370,8 @@  static const struct st_sensor_settings st_accel_sensors_settings[] = {
 			.mask_int2 = ST_ACCEL_2_DRDY_IRQ_INT2_MASK,
 			.addr_ihl = ST_ACCEL_2_IHL_IRQ_ADDR,
 			.mask_ihl = ST_ACCEL_2_IHL_IRQ_MASK,
+			.addr_od = ST_ACCEL_2_OD_IRQ_ADDR,
+			.mask_od = ST_ACCEL_2_OD_IRQ_MASK,
 		},
 		.multi_read_bit = ST_ACCEL_2_MULTIREAD_BIT,
 		.bootime = 2,
@@ -552,6 +558,8 @@  static const struct st_sensor_settings st_accel_sensors_settings[] = {
 			.mask_int2 = ST_ACCEL_5_DRDY_IRQ_INT2_MASK,
 			.addr_ihl = ST_ACCEL_5_IHL_IRQ_ADDR,
 			.mask_ihl = ST_ACCEL_5_IHL_IRQ_MASK,
+			.addr_od = ST_ACCEL_5_OD_IRQ_ADDR,
+			.mask_od = ST_ACCEL_5_OD_IRQ_MASK,
 		},
 		.multi_read_bit = ST_ACCEL_5_MULTIREAD_BIT,
 		.bootime = 2, /* guess */
diff --git a/drivers/iio/common/st_sensors/st_sensors_core.c b/drivers/iio/common/st_sensors/st_sensors_core.c
index ed6f54d5c932..bff469dd9583 100644
--- a/drivers/iio/common/st_sensors/st_sensors_core.c
+++ b/drivers/iio/common/st_sensors/st_sensors_core.c
@@ -302,6 +302,14 @@  static int st_sensors_set_drdy_int_pin(struct iio_dev *indio_dev,
 		return -EINVAL;
 	}
 
+	if (pdata->open_drain) {
+		if (!sdata->sensor_settings->drdy_irq.addr_od)
+			dev_err(&indio_dev->dev,
+				"open drain requested but unsupported.\n");
+		else
+			sdata->int_pin_open_drain = true;
+	}
+
 	return 0;
 }
 
@@ -322,6 +330,8 @@  static struct st_sensors_platform_data *st_sensors_of_probe(struct device *dev,
 	else
 		pdata->drdy_int_pin = defdata ? defdata->drdy_int_pin : 0;
 
+	pdata->open_drain = of_property_read_bool(np, "st,int-pin-open-drain");
+
 	return pdata;
 }
 #else
@@ -375,6 +385,16 @@  int st_sensors_init_sensor(struct iio_dev *indio_dev,
 			return err;
 	}
 
+	if (sdata->int_pin_open_drain) {
+		dev_info(&indio_dev->dev,
+			 "set interrupt line to open drain mode\n");
+		err = st_sensors_write_data_with_mask(indio_dev,
+				sdata->sensor_settings->drdy_irq.addr_od,
+				sdata->sensor_settings->drdy_irq.mask_od, 1);
+		if (err < 0)
+			return err;
+	}
+
 	err = st_sensors_set_axis_enable(indio_dev, ST_SENSORS_ENABLE_ALL_AXIS);
 
 	return err;
diff --git a/drivers/iio/common/st_sensors/st_sensors_trigger.c b/drivers/iio/common/st_sensors/st_sensors_trigger.c
index cb53d14aca94..4283468fd502 100644
--- a/drivers/iio/common/st_sensors/st_sensors_trigger.c
+++ b/drivers/iio/common/st_sensors/st_sensors_trigger.c
@@ -67,6 +67,15 @@  int st_sensors_allocate_trigger(struct iio_dev *indio_dev,
 			"rising edge\n", irq_trig);
 		irq_trig = IRQF_TRIGGER_RISING;
 	}
+
+	/*
+	 * If the interrupt pin is Open Drain, by definition this
+	 * means that the interrupt line may be shared with other
+	 * peripherals.
+	 */
+	if (sdata->int_pin_open_drain)
+		irq_trig |= IRQF_SHARED;
+
 	err = request_any_context_irq(irq,
 			iio_trigger_generic_data_rdy_poll,
 			irq_trig,
diff --git a/drivers/iio/gyro/st_gyro_core.c b/drivers/iio/gyro/st_gyro_core.c
index 260bfe021904..d53622b0e430 100644
--- a/drivers/iio/gyro/st_gyro_core.c
+++ b/drivers/iio/gyro/st_gyro_core.c
@@ -63,6 +63,8 @@ 
 #define ST_GYRO_1_DRDY_IRQ_INT2_MASK		0x08
 #define ST_GYRO_1_IHL_IRQ_ADDR			0x22
 #define ST_GYRO_1_IHL_IRQ_MASK			0x20
+#define ST_GYRO_1_OD_IRQ_ADDR			0x22
+#define ST_GYRO_1_OD_IRQ_MASK			0x10
 #define ST_GYRO_1_MULTIREAD_BIT			true
 
 /* CUSTOM VALUES FOR SENSOR 2 */
@@ -89,6 +91,8 @@ 
 #define ST_GYRO_2_DRDY_IRQ_INT2_MASK		0x08
 #define ST_GYRO_2_IHL_IRQ_ADDR			0x22
 #define ST_GYRO_2_IHL_IRQ_MASK			0x20
+#define ST_GYRO_2_OD_IRQ_ADDR			0x22
+#define ST_GYRO_2_OD_IRQ_MASK			0x10
 #define ST_GYRO_2_MULTIREAD_BIT			true
 
 /* CUSTOM VALUES FOR SENSOR 3 */
@@ -115,6 +119,8 @@ 
 #define ST_GYRO_3_DRDY_IRQ_INT2_MASK		0x08
 #define ST_GYRO_3_IHL_IRQ_ADDR			0x22
 #define ST_GYRO_3_IHL_IRQ_MASK			0x20
+#define ST_GYRO_3_OD_IRQ_ADDR			0x22
+#define ST_GYRO_3_OD_IRQ_MASK			0x10
 #define ST_GYRO_3_MULTIREAD_BIT			true
 
 
@@ -193,6 +199,8 @@  static const struct st_sensor_settings st_gyro_sensors_settings[] = {
 			.mask_int2 = ST_GYRO_1_DRDY_IRQ_INT2_MASK,
 			.addr_ihl = ST_GYRO_1_IHL_IRQ_ADDR,
 			.mask_ihl = ST_GYRO_1_IHL_IRQ_MASK,
+			.addr_od = ST_GYRO_1_OD_IRQ_ADDR,
+			.mask_od = ST_GYRO_1_OD_IRQ_MASK,
 		},
 		.multi_read_bit = ST_GYRO_1_MULTIREAD_BIT,
 		.bootime = 2,
@@ -258,6 +266,8 @@  static const struct st_sensor_settings st_gyro_sensors_settings[] = {
 			.mask_int2 = ST_GYRO_2_DRDY_IRQ_INT2_MASK,
 			.addr_ihl = ST_GYRO_2_IHL_IRQ_ADDR,
 			.mask_ihl = ST_GYRO_2_IHL_IRQ_MASK,
+			.addr_od = ST_GYRO_2_OD_IRQ_ADDR,
+			.mask_od = ST_GYRO_2_OD_IRQ_MASK,
 		},
 		.multi_read_bit = ST_GYRO_2_MULTIREAD_BIT,
 		.bootime = 2,
@@ -319,6 +329,8 @@  static const struct st_sensor_settings st_gyro_sensors_settings[] = {
 			.mask_int2 = ST_GYRO_3_DRDY_IRQ_INT2_MASK,
 			.addr_ihl = ST_GYRO_3_IHL_IRQ_ADDR,
 			.mask_ihl = ST_GYRO_3_IHL_IRQ_MASK,
+			.addr_od = ST_GYRO_3_OD_IRQ_ADDR,
+			.mask_od = ST_GYRO_3_OD_IRQ_MASK,
 		},
 		.multi_read_bit = ST_GYRO_3_MULTIREAD_BIT,
 		.bootime = 2,
diff --git a/drivers/iio/pressure/st_pressure_core.c b/drivers/iio/pressure/st_pressure_core.c
index 172393ad34af..38186288f79c 100644
--- a/drivers/iio/pressure/st_pressure_core.c
+++ b/drivers/iio/pressure/st_pressure_core.c
@@ -64,6 +64,8 @@ 
 #define ST_PRESS_LPS331AP_DRDY_IRQ_INT2_MASK	0x20
 #define ST_PRESS_LPS331AP_IHL_IRQ_ADDR		0x22
 #define ST_PRESS_LPS331AP_IHL_IRQ_MASK		0x80
+#define ST_PRESS_LPS331AP_OD_IRQ_ADDR		0x22
+#define ST_PRESS_LPS331AP_OD_IRQ_MASK		0x40
 #define ST_PRESS_LPS331AP_MULTIREAD_BIT		true
 #define ST_PRESS_LPS331AP_TEMP_OFFSET		42500
 
@@ -104,6 +106,8 @@ 
 #define ST_PRESS_LPS25H_DRDY_IRQ_INT2_MASK	0x10
 #define ST_PRESS_LPS25H_IHL_IRQ_ADDR		0x22
 #define ST_PRESS_LPS25H_IHL_IRQ_MASK		0x80
+#define ST_PRESS_LPS25H_OD_IRQ_ADDR		0x22
+#define ST_PRESS_LPS25H_OD_IRQ_MASK		0x40
 #define ST_PRESS_LPS25H_MULTIREAD_BIT		true
 #define ST_PRESS_LPS25H_TEMP_OFFSET		42500
 #define ST_PRESS_LPS25H_OUT_XL_ADDR		0x28
@@ -226,6 +230,8 @@  static const struct st_sensor_settings st_press_sensors_settings[] = {
 			.mask_int2 = ST_PRESS_LPS331AP_DRDY_IRQ_INT2_MASK,
 			.addr_ihl = ST_PRESS_LPS331AP_IHL_IRQ_ADDR,
 			.mask_ihl = ST_PRESS_LPS331AP_IHL_IRQ_MASK,
+			.addr_od = ST_PRESS_LPS331AP_OD_IRQ_ADDR,
+			.mask_od = ST_PRESS_LPS331AP_OD_IRQ_MASK,
 		},
 		.multi_read_bit = ST_PRESS_LPS331AP_MULTIREAD_BIT,
 		.bootime = 2,
@@ -312,6 +318,8 @@  static const struct st_sensor_settings st_press_sensors_settings[] = {
 			.mask_int2 = ST_PRESS_LPS25H_DRDY_IRQ_INT2_MASK,
 			.addr_ihl = ST_PRESS_LPS25H_IHL_IRQ_ADDR,
 			.mask_ihl = ST_PRESS_LPS25H_IHL_IRQ_MASK,
+			.addr_od = ST_PRESS_LPS25H_OD_IRQ_ADDR,
+			.mask_od = ST_PRESS_LPS25H_OD_IRQ_MASK,
 		},
 		.multi_read_bit = ST_PRESS_LPS25H_MULTIREAD_BIT,
 		.bootime = 2,
diff --git a/include/linux/iio/common/st_sensors.h b/include/linux/iio/common/st_sensors.h
index 6670c3d25c58..8972101224d9 100644
--- a/include/linux/iio/common/st_sensors.h
+++ b/include/linux/iio/common/st_sensors.h
@@ -121,6 +121,8 @@  struct st_sensor_bdu {
  * @mask_int2: mask to enable/disable IRQ on INT2 pin.
  * @addr_ihl: address to enable/disable active low on the INT lines.
  * @mask_ihl: mask to enable/disable active low on the INT lines.
+ * @addr_od: address to enable/disable Open Drain on the INT lines.
+ * @mask_od: mask to enable/disable Open Drain on the INT lines.
  * struct ig1 - represents the Interrupt Generator 1 of sensors.
  * @en_addr: address of the enable ig1 register.
  * @en_mask: mask to write the on/off value for enable.
@@ -131,6 +133,8 @@  struct st_sensor_data_ready_irq {
 	u8 mask_int2;
 	u8 addr_ihl;
 	u8 mask_ihl;
+	u8 addr_od;
+	u8 mask_od;
 	struct {
 		u8 en_addr;
 		u8 en_mask;
@@ -212,6 +216,7 @@  struct st_sensor_settings {
  * @odr: Output data rate of the sensor [Hz].
  * num_data_channels: Number of data channels used in buffer.
  * @drdy_int_pin: Redirect DRDY on pin 1 (1) or pin 2 (2).
+ * @int_pin_open_drain: Set the interrupt/DRDY to open drain.
  * @get_irq_data_ready: Function to get the IRQ used for data ready signal.
  * @tf: Transfer function structure used by I/O operations.
  * @tb: Transfer buffers and mutex used by I/O operations.
@@ -233,6 +238,7 @@  struct st_sensor_data {
 	unsigned int num_data_channels;
 
 	u8 drdy_int_pin;
+	bool int_pin_open_drain;
 
 	unsigned int (*get_irq_data_ready) (struct iio_dev *indio_dev);
 
diff --git a/include/linux/platform_data/st_sensors_pdata.h b/include/linux/platform_data/st_sensors_pdata.h
index 753839187ba0..79b0e4cdb814 100644
--- a/include/linux/platform_data/st_sensors_pdata.h
+++ b/include/linux/platform_data/st_sensors_pdata.h
@@ -16,9 +16,11 @@ 
  * @drdy_int_pin: Redirect DRDY on pin 1 (1) or pin 2 (2).
  *	Available only for accelerometer and pressure sensors.
  *	Accelerometer DRDY on LSM330 available only on pin 1 (see datasheet).
+ * @open_drain: set the interrupt line to be open drain if possible.
  */
 struct st_sensors_platform_data {
 	u8 drdy_int_pin;
+	bool open_drain;
 };
 
 #endif /* ST_SENSORS_PDATA_H */