Input: pwm-beeper - add devicetree probing support

A very simple binding, the only property is the phandle to the PWM.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Reviewed-by: Thierry Reding <thierry.reding@avionic-design.de>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
diff --git a/Documentation/devicetree/bindings/input/pwm-beeper.txt b/Documentation/devicetree/bindings/input/pwm-beeper.txt
new file mode 100644
index 0000000..be332ae
--- /dev/null
+++ b/Documentation/devicetree/bindings/input/pwm-beeper.txt
@@ -0,0 +1,7 @@
+* 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