pwm-audio-pi-zero-overlay.dts

/dts-v1/;
/plugin/;

/ {
  compatible = "brcm,bcm2708";

  fragment@0 {
    target = <&gpio>;
    __overlay__ {
      pinctrl-names = "default";
      pinctrl-0 = <&pwm_audio_pins>;

    pwm_audio_pins: pwm_audio_pins {
	brcm,pins = <13 18>;   /* gpio no ('BCM' number) */
	brcm,function = <4 2>; /* 0:in, 1:out, 2: alt5, 3: alt4, 4: alt0, 5: alt1, 6: alt2, 7: alt3 */
	brcm,pull = <0 0>;     /* 2:up 1:down 0:none */
      };
    };
  };
 };