[PATCH v5 0/4] iio: magnetometer: ak8975: Add gpio reset support

[PATCH v5 0/4] iio: magnetometer: ak8975: Add gpio reset support

[Jonathan Albrieux]

v5:
 - add maintainer

v4:
 - fix some typo
 - use gpio's dt-bindings for more clarity in documentation
 - set compatible properties without vendor prefix as deprecated
https://lore.kernel.org/linux-iio/20200520073125.30808-1-jonathan.albrieux@gmail.com/

v3:
 - fix patch messages style
 - align reset gpio comment to kernel doc reccomendation
 - introduce changelog
https://lore.kernel.org/linux-iio/20200519124402.26076-1-jonathan.albrieux@gmail.com/

v2:
 - rewording of reset gpio comment and patch messages to better clarify
   reset gpio behaviour
https://lore.kernel.org/linux-iio/20200518133645.19127-1-jonathan.albrieux@gmail.com/

v1:
 - initial patch submission
https://lore.kernel.org/linux-iio/20200519065749.4624-1-jonathan.albrieux@gmail.com/

Convert documentation from txt format to yaml. Add documentation about
reset-gpio.

Deassert reset on ak8975_power_on(), assert reset on ak8975_power_off().

Without reset's deassertion during ak8975_power_on(), driver's probe fails
on ak8975_who_i_am() while checking for device identity for AK09911 chip.

AK09911 has an active low reset gpio to handle register's reset.
AK09911 datasheet says that, if not used, reset pin should be connected
to VID. This patch emulates this situation.

Jonathan Albrieux (4):
  dt-bindings: iio: magnetometer: ak8975: convert format to yaml, add
    maintainer
  dt-bindings: iio: magnetometer: ak8975: add gpio reset support
  iio: magnetometer: ak8975: Fix typo, uniform measurement unit style
  iio: magnetometer: ak8975: Add gpio reset support

 .../bindings/iio/magnetometer/ak8975.txt      | 30 --------
 .../bindings/iio/magnetometer/ak8975.yaml     | 77 +++++++++++++++++++
 drivers/iio/magnetometer/ak8975.c             | 22 +++++-
 3 files changed, 97 insertions(+), 32 deletions(-)
 delete mode 100644 Documentation/devicetree/bindings/iio/magnetometer/ak8975.txt
 create mode 100644 Documentation/devicetree/bindings/iio/magnetometer/ak8975.yaml

-- 
2.17.1

[PATCH v5 1/4] dt-bindings: iio: magnetometer: ak8975: convert format to yaml, add maintainer

[Jonathan Albrieux]

Converts documentation from txt format to yaml.

Signed-off-by: Jonathan Albrieux <jonathan.albrieux@gmail.com>
---
 .../bindings/iio/magnetometer/ak8975.txt      | 30 --------
 .../bindings/iio/magnetometer/ak8975.yaml     | 71 +++++++++++++++++++
 2 files changed, 71 insertions(+), 30 deletions(-)
 delete mode 100644 Documentation/devicetree/bindings/iio/magnetometer/ak8975.txt
 create mode 100644 Documentation/devicetree/bindings/iio/magnetometer/ak8975.yaml

diff --git a/Documentation/devicetree/bindings/iio/magnetometer/ak8975.txt b/Documentation/devicetree/bindings/iio/magnetometer/ak8975.txt
deleted file mode 100644
index aa67ceb0d4e0..000000000000
--- a/Documentation/devicetree/bindings/iio/magnetometer/ak8975.txt
+++ /dev/null
@@ -1,30 +0,0 @@
-* AsahiKASEI AK8975 magnetometer sensor
-
-Required properties:
-
-  - compatible : should be "asahi-kasei,ak8975"
-  - reg : the I2C address of the magnetometer
-
-Optional properties:
-
-  - gpios : should be device tree identifier of the magnetometer DRDY pin
-  - vdd-supply: an optional regulator that needs to be on to provide VDD
-  - mount-matrix: an optional 3x3 mounting rotation matrix
-
-Example:
-
-ak8975@c {
-        compatible = "asahi-kasei,ak8975";
-        reg = <0x0c>;
-        gpios = <&gpj0 7 0>;
-        vdd-supply = <&ldo_3v3_gnss>;
-        mount-matrix = "-0.984807753012208",  /* x0 */
-                       "0",                   /* y0 */
-                       "-0.173648177666930",  /* z0 */
-                       "0",                   /* x1 */
-                       "-1",                  /* y1 */
-                       "0",                   /* z1 */
-                       "-0.173648177666930",  /* x2 */
-                       "0",                   /* y2 */
-                       "0.984807753012208";   /* z2 */
-};
diff --git a/Documentation/devicetree/bindings/iio/magnetometer/ak8975.yaml b/Documentation/devicetree/bindings/iio/magnetometer/ak8975.yaml
new file mode 100644
index 000000000000..8bde423a2ffa
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/magnetometer/ak8975.yaml
@@ -0,0 +1,71 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/magnetometer/ak8975.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: AsahiKASEI AK8975 magnetometer sensor
+
+maintainers:
+  - Jonathan Albrieux <jonathan.albrieux@gmail.com>
+
+properties:
+  compatible:
+    oneOf:
+      - const: asahi-kasei,ak8975
+      - const: asahi-kasei,ak8963
+      - const: asahi-kasei,ak09911
+      - const: asahi-kasei,ak09912
+      - const: ak8975
+        deprecated: true
+      - const: ak8963
+        deprecated: true
+      - const: ak09911
+        deprecated: true
+      - const: ak09912
+        deprecated: true
+
+  reg:
+    maxItems: 1
+    description: the I2C address of the magnetometer
+
+  gpios:
+    description: should be device tree identifier of the magnetometer DRDY pin
+
+  vdd-supply:
+    maxItems: 1
+    description: |
+      an optional regulator that needs to be on to provide VDD power to
+      the sensor.
+
+  mount-matrix:
+    description: an optional 3x3 mounting rotation matrix
+
+required:
+  - compatible
+  - reg
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+    i2c@78b7000 {
+        reg = <0x78b6000 0x600>;
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        magnetometer@c {
+            compatible = "asahi-kasei,ak8975";
+            reg = <0x0c>;
+            gpios = <&gpj0 7 GPIO_ACTIVE_HIGH>;
+            vdd-supply = <&ldo_3v3_gnss>;
+            mount-matrix = "-0.984807753012208",  /* x0 */
+                           "0",                   /* y0 */
+                           "-0.173648177666930",  /* z0 */
+                           "0",                   /* x1 */
+                           "-1",                  /* y1 */
+                           "0",                   /* z1 */
+                           "-0.173648177666930",  /* x2 */
+                           "0",                   /* y2 */
+                           "0.984807753012208";   /* z2 */
+        };
+    };
-- 
2.17.1

[PATCH v5 2/4] dt-bindings: iio: magnetometer: ak8975: add gpio reset support

[Jonathan Albrieux]

Add reset-gpio support.

Without reset's deassertion during ak8975_power_on(), driver's probe fails
on ak8975_who_i_am() while checking for device identity for AK09911 chip.

AK09911 has an active low reset gpio to handle register's reset.
AK09911 datasheet says that, if not used, reset pin should be connected
to VID. This patch emulates this situation.

Signed-off-by: Jonathan Albrieux <jonathan.albrieux@gmail.com>
---
 .../devicetree/bindings/iio/magnetometer/ak8975.yaml        | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/Documentation/devicetree/bindings/iio/magnetometer/ak8975.yaml b/Documentation/devicetree/bindings/iio/magnetometer/ak8975.yaml
index 8bde423a2ffa..aba9ced7b6da 100644
--- a/Documentation/devicetree/bindings/iio/magnetometer/ak8975.yaml
+++ b/Documentation/devicetree/bindings/iio/magnetometer/ak8975.yaml
@@ -41,6 +41,11 @@ properties:
   mount-matrix:
     description: an optional 3x3 mounting rotation matrix
 
+  reset-gpio:
+    description: |
+      an optional pin needed for AK09911 to set the reset state. This should
+      be usually active low
+
 required:
   - compatible
   - reg
@@ -58,6 +63,7 @@ examples:
             reg = <0x0c>;
             gpios = <&gpj0 7 GPIO_ACTIVE_HIGH>;
             vdd-supply = <&ldo_3v3_gnss>;
+            reset-gpio = <&msmgpio 111 GPIO_ACTIVE_LOW>;
             mount-matrix = "-0.984807753012208",  /* x0 */
                            "0",                   /* y0 */
                            "-0.173648177666930",  /* z0 */
-- 
2.17.1

[PATCH v5 3/4] iio: magnetometer: ak8975: Fix typo, uniform measurement unit style

[Jonathan Albrieux]

Minor comment style edits.

Signed-off-by: Jonathan Albrieux <jonathan.albrieux@gmail.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 drivers/iio/magnetometer/ak8975.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/magnetometer/ak8975.c b/drivers/iio/magnetometer/ak8975.c
index 3c881541ae72..fd368455cd7b 100644
--- a/drivers/iio/magnetometer/ak8975.c
+++ b/drivers/iio/magnetometer/ak8975.c
@@ -385,9 +385,9 @@ static int ak8975_power_on(const struct ak8975_data *data)
 		return ret;
 	}
 	/*
-	 * According to the datasheet the power supply rise time i 200us
+	 * According to the datasheet the power supply rise time is 200us
 	 * and the minimum wait time before mode setting is 100us, in
-	 * total 300 us. Add some margin and say minimum 500us here.
+	 * total 300us. Add some margin and say minimum 500us here.
 	 */
 	usleep_range(500, 1000);
 	return 0;
-- 
2.17.1

[PATCH v5 4/4] iio: magnetometer: ak8975: Add gpio reset support

[Jonathan Albrieux]

According to AK09911 datasheet, if reset gpio is provided then
deassert reset on ak8975_power_on() and assert reset on ak8975_power_off().

Without reset's deassertion during ak8975_power_on(), driver's probe fails
on ak8975_who_i_am() while checking for device identity for AK09911 chip.

AK09911 has an active low reset gpio to handle register's reset.
AK09911 datasheet says that, if not used, reset pin should be connected
to VID. This patch emulates this situation.

Signed-off-by: Jonathan Albrieux <jonathan.albrieux@gmail.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Stephan Gerhold <stephan@gerhold.net>
---
 drivers/iio/magnetometer/ak8975.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/drivers/iio/magnetometer/ak8975.c b/drivers/iio/magnetometer/ak8975.c
index fd368455cd7b..a23422aad97d 100644
--- a/drivers/iio/magnetometer/ak8975.c
+++ b/drivers/iio/magnetometer/ak8975.c
@@ -358,6 +358,7 @@ struct ak8975_data {
 	u8			asa[3];
 	long			raw_to_gauss[3];
 	struct gpio_desc	*eoc_gpiod;
+	struct gpio_desc	*reset_gpiod;
 	int			eoc_irq;
 	wait_queue_head_t	data_ready_queue;
 	unsigned long		flags;
@@ -384,6 +385,9 @@ static int ak8975_power_on(const struct ak8975_data *data)
 			 "Failed to enable specified Vid supply\n");
 		return ret;
 	}
+
+	gpiod_set_value_cansleep(data->reset_gpiod, 0);
+
 	/*
 	 * According to the datasheet the power supply rise time is 200us
 	 * and the minimum wait time before mode setting is 100us, in
@@ -396,6 +400,8 @@ static int ak8975_power_on(const struct ak8975_data *data)
 /* Disable attached power regulator if any. */
 static void ak8975_power_off(const struct ak8975_data *data)
 {
+	gpiod_set_value_cansleep(data->reset_gpiod, 1);
+
 	regulator_disable(data->vid);
 	regulator_disable(data->vdd);
 }
@@ -839,6 +845,7 @@ static int ak8975_probe(struct i2c_client *client,
 	struct ak8975_data *data;
 	struct iio_dev *indio_dev;
 	struct gpio_desc *eoc_gpiod;
+	struct gpio_desc *reset_gpiod;
 	const void *match;
 	unsigned int i;
 	int err;
@@ -856,6 +863,16 @@ static int ak8975_probe(struct i2c_client *client,
 	if (eoc_gpiod)
 		gpiod_set_consumer_name(eoc_gpiod, "ak_8975");
 
+	/*
+	 * According to AK09911 datasheet, if reset GPIO is provided then
+	 * deassert reset on ak8975_power_on() and assert reset on
+	 * ak8975_power_off().
+	 */
+	reset_gpiod = devm_gpiod_get_optional(&client->dev,
+					      "reset", GPIOD_OUT_HIGH);
+	if (IS_ERR(reset_gpiod))
+		return PTR_ERR(reset_gpiod);
+
 	/* Register with IIO */
 	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 	if (indio_dev == NULL)
@@ -866,6 +883,7 @@ static int ak8975_probe(struct i2c_client *client,
 
 	data->client = client;
 	data->eoc_gpiod = eoc_gpiod;
+	data->reset_gpiod = reset_gpiod;
 	data->eoc_irq = 0;
 
 	err = iio_read_mount_matrix(&client->dev, "mount-matrix", &data->orientation);
-- 
2.17.1

Re: [PATCH v5 1/4] dt-bindings: iio: magnetometer: ak8975: convert format to yaml, add maintainer

[Jonathan Cameron]

On Wed, 20 May 2020 18:34:06 +0200
Jonathan Albrieux <jonathan.albrieux@gmail.com> wrote:

> Converts documentation from txt format to yaml.
> 
> Signed-off-by: Jonathan Albrieux <jonathan.albrieux@gmail.com>

An additional request inline.  Doesn't effect this patch 'as such'.

Also the file name thing just below here.

> ---
>  .../bindings/iio/magnetometer/ak8975.txt      | 30 --------
>  .../bindings/iio/magnetometer/ak8975.yaml     | 71 +++++++++++++++++++
File naming should match the compatible.

ashahi-kasei,ak8975.yaml

>  2 files changed, 71 insertions(+), 30 deletions(-)
>  delete mode 100644 Documentation/devicetree/bindings/iio/magnetometer/ak8975.txt
>  create mode 100644 Documentation/devicetree/bindings/iio/magnetometer/ak8975.yaml
> 
> diff --git a/Documentation/devicetree/bindings/iio/magnetometer/ak8975.txt b/Documentation/devicetree/bindings/iio/magnetometer/ak8975.txt
> deleted file mode 100644
> index aa67ceb0d4e0..000000000000
> --- a/Documentation/devicetree/bindings/iio/magnetometer/ak8975.txt
> +++ /dev/null
> @@ -1,30 +0,0 @@
> -* AsahiKASEI AK8975 magnetometer sensor
> -
> -Required properties:
> -
> -  - compatible : should be "asahi-kasei,ak8975"
> -  - reg : the I2C address of the magnetometer
> -
> -Optional properties:
> -
> -  - gpios : should be device tree identifier of the magnetometer DRDY pin
> -  - vdd-supply: an optional regulator that needs to be on to provide VDD
> -  - mount-matrix: an optional 3x3 mounting rotation matrix
> -
> -Example:
> -
> -ak8975@c {
> -        compatible = "asahi-kasei,ak8975";
> -        reg = <0x0c>;
> -        gpios = <&gpj0 7 0>;
> -        vdd-supply = <&ldo_3v3_gnss>;
> -        mount-matrix = "-0.984807753012208",  /* x0 */
> -                       "0",                   /* y0 */
> -                       "-0.173648177666930",  /* z0 */
> -                       "0",                   /* x1 */
> -                       "-1",                  /* y1 */
> -                       "0",                   /* z1 */
> -                       "-0.173648177666930",  /* x2 */
> -                       "0",                   /* y2 */
> -                       "0.984807753012208";   /* z2 */
> -};
> diff --git a/Documentation/devicetree/bindings/iio/magnetometer/ak8975.yaml b/Documentation/devicetree/bindings/iio/magnetometer/ak8975.yaml
> new file mode 100644
> index 000000000000..8bde423a2ffa
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/magnetometer/ak8975.yaml
> @@ -0,0 +1,71 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/iio/magnetometer/ak8975.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: AsahiKASEI AK8975 magnetometer sensor
> +
> +maintainers:
> +  - Jonathan Albrieux <jonathan.albrieux@gmail.com>
> +
> +properties:
> +  compatible:
> +    oneOf:
> +      - const: asahi-kasei,ak8975
> +      - const: asahi-kasei,ak8963
> +      - const: asahi-kasei,ak09911
> +      - const: asahi-kasei,ak09912
> +      - const: ak8975
> +        deprecated: true
> +      - const: ak8963
> +        deprecated: true
> +      - const: ak09911
> +        deprecated: true
> +      - const: ak09912
> +        deprecated: true
> +
> +  reg:
> +    maxItems: 1
> +    description: the I2C address of the magnetometer
> +
> +  gpios:
> +    description: should be device tree identifier of the magnetometer DRDY pin

Nothing to do with your patch obviously but this is horrible...
+ the driver will quite happily take an interrupt instead.

Do you mind documenting the interrupt here as well?

Should be a separate patch though.  So a follow up one to
this one.  The 
arch/arm/boot/dts/motorola-mapphone-common.dtsi
does it that way, unlike the samsung s3 which uses the gpio
binding (I think it's the only one against quite a few
using interrupts).

Also switch the example to an interrupts one so we don't
encourage anyone to go the gpios route.

Note can be a follow up if this series is otherwise ready to go.


> +
> +  vdd-supply:
> +    maxItems: 1
> +    description: |
> +      an optional regulator that needs to be on to provide VDD power to
> +      the sensor.
> +
> +  mount-matrix:
> +    description: an optional 3x3 mounting rotation matrix
> +
> +required:
> +  - compatible
> +  - reg
> +
> +examples:
> +  - |
> +    #include <dt-bindings/gpio/gpio.h>
> +    i2c@78b7000 {
> +        reg = <0x78b6000 0x600>;
> +        #address-cells = <1>;
> +        #size-cells = <0>;
> +
> +        magnetometer@c {
> +            compatible = "asahi-kasei,ak8975";
> +            reg = <0x0c>;
> +            gpios = <&gpj0 7 GPIO_ACTIVE_HIGH>;
> +            vdd-supply = <&ldo_3v3_gnss>;
> +            mount-matrix = "-0.984807753012208",  /* x0 */
> +                           "0",                   /* y0 */
> +                           "-0.173648177666930",  /* z0 */
> +                           "0",                   /* x1 */
> +                           "-1",                  /* y1 */
> +                           "0",                   /* z1 */
> +                           "-0.173648177666930",  /* x2 */
> +                           "0",                   /* y2 */
> +                           "0.984807753012208";   /* z2 */
> +        };
> +    };

Re: [PATCH v5 4/4] iio: magnetometer: ak8975: Add gpio reset support

[Jonathan Cameron]

On Wed, 20 May 2020 18:34:09 +0200
Jonathan Albrieux <jonathan.albrieux@gmail.com> wrote:

> According to AK09911 datasheet, if reset gpio is provided then
> deassert reset on ak8975_power_on() and assert reset on ak8975_power_off().
> 
> Without reset's deassertion during ak8975_power_on(), driver's probe fails
> on ak8975_who_i_am() while checking for device identity for AK09911 chip.
> 
> AK09911 has an active low reset gpio to handle register's reset.
> AK09911 datasheet says that, if not used, reset pin should be connected
> to VID. This patch emulates this situation.
> 
> Signed-off-by: Jonathan Albrieux <jonathan.albrieux@gmail.com>
> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> Reviewed-by: Stephan Gerhold <stephan@gerhold.net>
Looks good to me.  Just the minor stuff with the binding plus
giving time for a binding review to go.

Thanks,

Jonathan

> ---
>  drivers/iio/magnetometer/ak8975.c | 18 ++++++++++++++++++
>  1 file changed, 18 insertions(+)
> 
> diff --git a/drivers/iio/magnetometer/ak8975.c b/drivers/iio/magnetometer/ak8975.c
> index fd368455cd7b..a23422aad97d 100644
> --- a/drivers/iio/magnetometer/ak8975.c
> +++ b/drivers/iio/magnetometer/ak8975.c
> @@ -358,6 +358,7 @@ struct ak8975_data {
>  	u8			asa[3];
>  	long			raw_to_gauss[3];
>  	struct gpio_desc	*eoc_gpiod;
> +	struct gpio_desc	*reset_gpiod;
>  	int			eoc_irq;
>  	wait_queue_head_t	data_ready_queue;
>  	unsigned long		flags;
> @@ -384,6 +385,9 @@ static int ak8975_power_on(const struct ak8975_data *data)
>  			 "Failed to enable specified Vid supply\n");
>  		return ret;
>  	}
> +
> +	gpiod_set_value_cansleep(data->reset_gpiod, 0);
> +
>  	/*
>  	 * According to the datasheet the power supply rise time is 200us
>  	 * and the minimum wait time before mode setting is 100us, in
> @@ -396,6 +400,8 @@ static int ak8975_power_on(const struct ak8975_data *data)
>  /* Disable attached power regulator if any. */
>  static void ak8975_power_off(const struct ak8975_data *data)
>  {
> +	gpiod_set_value_cansleep(data->reset_gpiod, 1);
> +
>  	regulator_disable(data->vid);
>  	regulator_disable(data->vdd);
>  }
> @@ -839,6 +845,7 @@ static int ak8975_probe(struct i2c_client *client,
>  	struct ak8975_data *data;
>  	struct iio_dev *indio_dev;
>  	struct gpio_desc *eoc_gpiod;
> +	struct gpio_desc *reset_gpiod;
>  	const void *match;
>  	unsigned int i;
>  	int err;
> @@ -856,6 +863,16 @@ static int ak8975_probe(struct i2c_client *client,
>  	if (eoc_gpiod)
>  		gpiod_set_consumer_name(eoc_gpiod, "ak_8975");
>  
> +	/*
> +	 * According to AK09911 datasheet, if reset GPIO is provided then
> +	 * deassert reset on ak8975_power_on() and assert reset on
> +	 * ak8975_power_off().
> +	 */
> +	reset_gpiod = devm_gpiod_get_optional(&client->dev,
> +					      "reset", GPIOD_OUT_HIGH);
> +	if (IS_ERR(reset_gpiod))
> +		return PTR_ERR(reset_gpiod);
> +
>  	/* Register with IIO */
>  	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
>  	if (indio_dev == NULL)
> @@ -866,6 +883,7 @@ static int ak8975_probe(struct i2c_client *client,
>  
>  	data->client = client;
>  	data->eoc_gpiod = eoc_gpiod;
> +	data->reset_gpiod = reset_gpiod;
>  	data->eoc_irq = 0;
>  
>  	err = iio_read_mount_matrix(&client->dev, "mount-matrix", &data->orientation);

Re: [PATCH v5 1/4] dt-bindings: iio: magnetometer: ak8975: convert format to yaml, add maintainer

[Jonathan Albrieux]

On Sun, May 24, 2020 at 03:57:45PM +0100, Jonathan Cameron wrote:
> On Wed, 20 May 2020 18:34:06 +0200
> Jonathan Albrieux <jonathan.albrieux@gmail.com> wrote:
> 
> > Converts documentation from txt format to yaml.
> > 
> > Signed-off-by: Jonathan Albrieux <jonathan.albrieux@gmail.com>
> 
> An additional request inline.  Doesn't effect this patch 'as such'.
> 
> Also the file name thing just below here.
> 
> > ---
> >  .../bindings/iio/magnetometer/ak8975.txt      | 30 --------
> >  .../bindings/iio/magnetometer/ak8975.yaml     | 71 +++++++++++++++++++
> File naming should match the compatible.
> 
> ashahi-kasei,ak8975.yaml
>

Ok, I'll take this as general rule then :-)
 
> >  2 files changed, 71 insertions(+), 30 deletions(-)
> >  delete mode 100644 Documentation/devicetree/bindings/iio/magnetometer/ak8975.txt
> >  create mode 100644 Documentation/devicetree/bindings/iio/magnetometer/ak8975.yaml
> > 
> > diff --git a/Documentation/devicetree/bindings/iio/magnetometer/ak8975.txt b/Documentation/devicetree/bindings/iio/magnetometer/ak8975.txt
> > deleted file mode 100644
> > index aa67ceb0d4e0..000000000000
> > --- a/Documentation/devicetree/bindings/iio/magnetometer/ak8975.txt
> > +++ /dev/null
> > @@ -1,30 +0,0 @@
> > -* AsahiKASEI AK8975 magnetometer sensor
> > -
> > -Required properties:
> > -
> > -  - compatible : should be "asahi-kasei,ak8975"
> > -  - reg : the I2C address of the magnetometer
> > -
> > -Optional properties:
> > -
> > -  - gpios : should be device tree identifier of the magnetometer DRDY pin
> > -  - vdd-supply: an optional regulator that needs to be on to provide VDD
> > -  - mount-matrix: an optional 3x3 mounting rotation matrix
> > -
> > -Example:
> > -
> > -ak8975@c {
> > -        compatible = "asahi-kasei,ak8975";
> > -        reg = <0x0c>;
> > -        gpios = <&gpj0 7 0>;
> > -        vdd-supply = <&ldo_3v3_gnss>;
> > -        mount-matrix = "-0.984807753012208",  /* x0 */
> > -                       "0",                   /* y0 */
> > -                       "-0.173648177666930",  /* z0 */
> > -                       "0",                   /* x1 */
> > -                       "-1",                  /* y1 */
> > -                       "0",                   /* z1 */
> > -                       "-0.173648177666930",  /* x2 */
> > -                       "0",                   /* y2 */
> > -                       "0.984807753012208";   /* z2 */
> > -};
> > diff --git a/Documentation/devicetree/bindings/iio/magnetometer/ak8975.yaml b/Documentation/devicetree/bindings/iio/magnetometer/ak8975.yaml
> > new file mode 100644
> > index 000000000000..8bde423a2ffa
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/iio/magnetometer/ak8975.yaml
> > @@ -0,0 +1,71 @@
> > +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/iio/magnetometer/ak8975.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: AsahiKASEI AK8975 magnetometer sensor
> > +
> > +maintainers:
> > +  - Jonathan Albrieux <jonathan.albrieux@gmail.com>
> > +
> > +properties:
> > +  compatible:
> > +    oneOf:
> > +      - const: asahi-kasei,ak8975
> > +      - const: asahi-kasei,ak8963
> > +      - const: asahi-kasei,ak09911
> > +      - const: asahi-kasei,ak09912
> > +      - const: ak8975
> > +        deprecated: true
> > +      - const: ak8963
> > +        deprecated: true
> > +      - const: ak09911
> > +        deprecated: true
> > +      - const: ak09912
> > +        deprecated: true
> > +
> > +  reg:
> > +    maxItems: 1
> > +    description: the I2C address of the magnetometer
> > +
> > +  gpios:
> > +    description: should be device tree identifier of the magnetometer DRDY pin
> 
> Nothing to do with your patch obviously but this is horrible...
> + the driver will quite happily take an interrupt instead.
> 
> Do you mind documenting the interrupt here as well?
> 
> Should be a separate patch though.  So a follow up one to
> this one.  The 
> arch/arm/boot/dts/motorola-mapphone-common.dtsi
> does it that way, unlike the samsung s3 which uses the gpio
> binding (I think it's the only one against quite a few
> using interrupts).
> 
> Also switch the example to an interrupts one so we don't
> encourage anyone to go the gpios route.
> 
> Note can be a follow up if this series is otherwise ready to go.
> 

Oh ok, will add a new patch for that in this series if you don't
mind. It may even be better to split this series in two given
the amount of changes to the documentation outnumbered the changes
related to the driver itself, the first one regarding just the
conversion to yaml and clean-up-related changes to documentation
and the second one, depending on the first one, with the
reset-related changes.

Do you have advices on which of the two should be the best strategy?

I'll prepare both the versions today in order to choose the right
one once the path to follow has been decided,

Thank you,

Best regards,
Jonathan Albrieux

> 
> > +
> > +  vdd-supply:
> > +    maxItems: 1
> > +    description: |
> > +      an optional regulator that needs to be on to provide VDD power to
> > +      the sensor.
> > +
> > +  mount-matrix:
> > +    description: an optional 3x3 mounting rotation matrix
> > +
> > +required:
> > +  - compatible
> > +  - reg
> > +
> > +examples:
> > +  - |
> > +    #include <dt-bindings/gpio/gpio.h>
> > +    i2c@78b7000 {
> > +        reg = <0x78b6000 0x600>;
> > +        #address-cells = <1>;
> > +        #size-cells = <0>;
> > +
> > +        magnetometer@c {
> > +            compatible = "asahi-kasei,ak8975";
> > +            reg = <0x0c>;
> > +            gpios = <&gpj0 7 GPIO_ACTIVE_HIGH>;
> > +            vdd-supply = <&ldo_3v3_gnss>;
> > +            mount-matrix = "-0.984807753012208",  /* x0 */
> > +                           "0",                   /* y0 */
> > +                           "-0.173648177666930",  /* z0 */
> > +                           "0",                   /* x1 */
> > +                           "-1",                  /* y1 */
> > +                           "0",                   /* z1 */
> > +                           "-0.173648177666930",  /* x2 */
> > +                           "0",                   /* y2 */
> > +                           "0.984807753012208";   /* z2 */
> > +        };
> > +    };
>