dt-bindings: Add devicetree bindings

Add snapshot of device tree bindings from keystone common kernel, branch
"android-mainline-keystone-qcom-release" at c4c12103f9c0 ("Snap for 9228065
from e32903b9a63bb558df8b803b076619c53c16baad to
android-mainline-keystone-qcom-release").

Change-Id: I7682079615cbd9f29340a5c1f2a1d84ec441a1f1
Signed-off-by: Melody Olvera <quic_molvera@quicinc.com>

bindings/leds/backlight/gpio-backlight.yaml

@@ -0,0 +1,41 @@
+# SPDX-License-Identifier: GPL-2.0-only
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/leds/backlight/gpio-backlight.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: gpio-backlight bindings
+
+maintainers:
+  - Lee Jones <lee@kernel.org>
+  - Daniel Thompson <daniel.thompson@linaro.org>
+  - Jingoo Han <jingoohan1@gmail.com>
+
+properties:
+  compatible:
+    const: gpio-backlight
+
+  gpios:
+    description: The gpio that is used for enabling/disabling the backlight.
+    maxItems: 1
+
+  default-on:
+    description: enable the backlight at boot.
+    type: boolean
+
+required:
+  - compatible
+  - gpios
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+    backlight {
+        compatible = "gpio-backlight";
+        gpios = <&gpio3 4 GPIO_ACTIVE_HIGH>;
+        default-on;
+    };
+
+...