linux/Documentation/devicetree/bindings/input/pwm-beeper.txt
<<
>>
Prefs
   1* PWM beeper device tree bindings
   2
   3Registers a PWM device as beeper.
   4
   5Required properties:
   6- compatible: should be "pwm-beeper"
   7- pwms: phandle to the physical PWM device
   8
   9Optional properties:
  10- amp-supply: phandle to a regulator that acts as an amplifier for the beeper
  11- beeper-hz:  bell frequency in Hz
  12
  13Example:
  14
  15beeper_amp: amplifier {
  16        compatible = "fixed-regulator";
  17        gpios = <&gpio0 1 GPIO_ACTIVE_HIGH>;
  18};
  19
  20beeper {
  21        compatible = "pwm-beeper";
  22        pwms = <&pwm0>;
  23        amp-supply = <&beeper_amp>;
  24};
  25