[PATCH v7 3/5] dt-bindings: iio: magnetometer: ak8975: add gpio reset support

[PATCH v7 3/5] 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>
Reviewed-by: Rob Herring <robh@kernel.org>
---
 .../bindings/iio/magnetometer/asahi-kasei,ak8975.yaml      | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/Documentation/devicetree/bindings/iio/magnetometer/asahi-kasei,ak8975.yaml b/Documentation/devicetree/bindings/iio/magnetometer/asahi-kasei,ak8975.yaml
index 55b18784e503..e8af53d60759 100644
--- a/Documentation/devicetree/bindings/iio/magnetometer/asahi-kasei,ak8975.yaml
+++ b/Documentation/devicetree/bindings/iio/magnetometer/asahi-kasei,ak8975.yaml
@@ -47,6 +47,11 @@ properties:
   mount-matrix:
     description: an optional 3x3 mounting rotation matrix.
 
+  reset-gpios:
+    description: |
+      an optional pin needed for AK09911 to set the reset state. This should
+      be usually active low
+
 required:
   - compatible
   - reg
@@ -54,6 +59,7 @@ required:
 examples:
   - |
     #include <dt-bindings/interrupt-controller/irq.h>
+    #include <dt-bindings/gpio/gpio.h>
     i2c {
         #address-cells = <1>;
         #size-cells = <0>;
@@ -64,6 +70,7 @@ examples:
             interrupt-parent = <&gpio6>;
             interrupts = <15 IRQ_TYPE_EDGE_RISING>;
             vdd-supply = <&ldo_3v3_gnss>;
+            reset-gpios = <&msmgpio 111 GPIO_ACTIVE_LOW>;
             mount-matrix = "-0.984807753012208",  /* x0 */
                            "0",                   /* y0 */
                            "-0.173648177666930",  /* z0 */
-- 
2.17.1

Re: [PATCH v7 3/5] dt-bindings: iio: magnetometer: ak8975: add gpio reset support

[Jonathan Cameron]

On Thu, 28 May 2020 16:59:28 +0200
Jonathan Albrieux <jonathan.albrieux@gmail.com> wrote:

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

Applied to the togreg branch of iio.git and pushed out as testing
for the autobuilders to play with it.

thanks,

Jonathan

> ---
>  .../bindings/iio/magnetometer/asahi-kasei,ak8975.yaml      | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/iio/magnetometer/asahi-kasei,ak8975.yaml b/Documentation/devicetree/bindings/iio/magnetometer/asahi-kasei,ak8975.yaml
> index 55b18784e503..e8af53d60759 100644
> --- a/Documentation/devicetree/bindings/iio/magnetometer/asahi-kasei,ak8975.yaml
> +++ b/Documentation/devicetree/bindings/iio/magnetometer/asahi-kasei,ak8975.yaml
> @@ -47,6 +47,11 @@ properties:
>    mount-matrix:
>      description: an optional 3x3 mounting rotation matrix.
>  
> +  reset-gpios:
> +    description: |
> +      an optional pin needed for AK09911 to set the reset state. This should
> +      be usually active low
> +
>  required:
>    - compatible
>    - reg
> @@ -54,6 +59,7 @@ required:
>  examples:
>    - |
>      #include <dt-bindings/interrupt-controller/irq.h>
> +    #include <dt-bindings/gpio/gpio.h>
>      i2c {
>          #address-cells = <1>;
>          #size-cells = <0>;
> @@ -64,6 +70,7 @@ examples:
>              interrupt-parent = <&gpio6>;
>              interrupts = <15 IRQ_TYPE_EDGE_RISING>;
>              vdd-supply = <&ldo_3v3_gnss>;
> +            reset-gpios = <&msmgpio 111 GPIO_ACTIVE_LOW>;
>              mount-matrix = "-0.984807753012208",  /* x0 */
>                             "0",                   /* y0 */
>                             "-0.173648177666930",  /* z0 */