[PATCH v6 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@xxxxxxxxx>
---
 .../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 a603659d5fa5..04b895c7143c 100644
--- a/Documentation/devicetree/bindings/iio/magnetometer/asahi-kasei,ak8975.yaml
+++ b/Documentation/devicetree/bindings/iio/magnetometer/asahi-kasei,ak8975.yaml
@@ -48,6 +48,11 @@ 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
@@ -55,6 +60,7 @@ required:
 examples:
   - |
     #include <dt-bindings/interrupt-controller/irq.h>
+    #include <dt-bindings/gpio/gpio.h>
     i2c {
         #address-cells = <1>;
         #size-cells = <0>;
@@ -65,6 +71,7 @@ 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