dt-bindings: Add binding document for NOA1305

Document the ON Semiconductor NOA1305 ambient light sensor devicetree
bindings.
Signed-off-by: Martyn Welch <martyn.welch@collabora.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Documentation/devicetree/bindings/iio/light/noa1305.yaml

+# SPDX-License-Identifier: GPL-2.0
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/light/noa1305.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: ON Semiconductor NOA1305 Ambient Light Sensor
+
+maintainers:
+  - Martyn Welch <martyn.welch@collabora.com>
+
+description: |
+  Ambient sensing with an i2c interface.
+
+  https://www.onsemi.com/pub/Collateral/NOA1305-D.PDF
+
+properties:
+  compatible:
+    enum:
+      - onnn,noa1305
+
+  reg:
+    maxItems: 1
+
+  vin-supply:
+    description: Regulator that provides power to the sensor
+
+required:
+  - compatible
+  - reg
+
+examples:
+  - |
+    i2c {
+
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        light@39 {
+                compatible = "onnn,noa1305";
+                reg = <0x39>;
+        };
+    };
+...