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/trigger-source.yaml

@@ -0,0 +1,26 @@
+# SPDX-License-Identifier: GPL-2.0-only
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/leds/trigger-source.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Trigger source providers
+
+maintainers:
+  - Jacek Anaszewski <jacek.anaszewski@gmail.com>
+  - Pavel Machek <pavel@ucw.cz>
+
+description:
+  Each trigger source provider should be represented by a device tree node. It
+  may be e.g. a USB port or an Ethernet device.
+
+properties:
+  '#trigger-source-cells':
+    description:
+      Number of cells in a source trigger. Typically 0 for nodes of simple
+      trigger sources (e.g. a specific USB port).
+    enum: [ 0, 1 ]
+
+additionalProperties: true
+
+...