[PATCH v3 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 datasheed 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>
---
 .../devicetree/bindings/iio/magnetometer/ak8975.yaml          | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Documentation/devicetree/bindings/iio/magnetometer/ak8975.yaml b/Documentation/devicetree/bindings/iio/magnetometer/ak8975.yaml
index 86e3efa693a8..a82c0ff5d098 100644
--- a/Documentation/devicetree/bindings/iio/magnetometer/ak8975.yaml
+++ b/Documentation/devicetree/bindings/iio/magnetometer/ak8975.yaml
@@ -37,6 +37,9 @@ properties:
   mount-matrix:
     description: an optional 3x3 mounting rotation matrix
 
+  reset-gpio:
+    description: an optional pin needed for AK09911 to set the reset state
+
 required:
   - compatible
   - reg
@@ -53,6 +56,7 @@ examples:
             reg = <0x0c>;
             gpios = <&gpj0 7 0>;
             vdd-supply = <&ldo_3v3_gnss>;
+            reset-gpio = <&msmgpio 111 1>;
             mount-matrix = "-0.984807753012208",  /* x0 */
                            "0",                   /* y0 */
                            "-0.173648177666930",  /* z0 */
-- 
2.17.1