dt-bindings: leds: document Panasonic AN30259A bindings

Signed-off-by: Simon Shields <simon@lineageos.org>
Acked-by: Pavel Machek <pavel@ucw.cz>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>

Documentation/devicetree/bindings/leds/leds-an30259a.txt

+* Panasonic AN30259A 3-channel LED driver
+
+The AN30259A is a LED controller capable of driving three LEDs independently. It supports
+constant current output and sloping current output modes. The chip is connected over I2C.
+
+Required properties:
+	- compatible: Must be "panasonic,an30259a".
+	- reg: I2C slave address.
+	- #address-cells: Must be 1.
+	- #size-cells: Must be 0.
+
+Each LED is represented as a sub-node of the panasonic,an30259a node.
+
+Required sub-node properties:
+	- reg: Pin that the LED is connected to. Must be 1, 2, or 3.
+
+Optional sub-node properties:
+	- label: see Documentation/devicetree/bindings/leds/common.txt
+	- linux,default-trigger: see Documentation/devicetree/bindings/leds/common.txt
+
+Example:
+led-controller@30 {
+	compatible = "panasonic,an30259a";
+	reg = <0x30>;
+	#address-cells = <1>;
+	#size-cells = <0>;
+
+	led@1 {
+		reg = <1>;
+		linux,default-trigger = "heartbeat";
+		label = "red:indicator";
+	};
+
+	led@2 {
+		reg = <2>;
+		label = "green:indicator";
+	};
+
+	led@3 {
+		reg = <3>;
+		label = "blue:indicator";
+	};
+};