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/input/pwm-beeper.txt

@@ -0,0 +1,24 @@
+* PWM beeper device tree bindings
+
+Registers a PWM device as beeper.
+
+Required properties:
+- compatible: should be "pwm-beeper"
+- pwms: phandle to the physical PWM device
+
+Optional properties:
+- amp-supply: phandle to a regulator that acts as an amplifier for the beeper
+- beeper-hz:  bell frequency in Hz
+
+Example:
+
+beeper_amp: amplifier {
+	compatible = "fixed-regulator";
+	gpios = <&gpio0 1 GPIO_ACTIVE_HIGH>;
+};
+
+beeper {
+	compatible = "pwm-beeper";
+	pwms = <&pwm0>;
+	amp-supply = <&beeper_amp>;
+};