CHIP-linux-libre/Documentation/devicetree/bindings/sound/sirf-audio.txt

* SiRF atlas6 and prima2 internal audio codec and port based audio setups

Required properties:
- compatible: "sirf,sirf-audio-card"
- sirf,audio-platform: phandle for the platform node
- sirf,audio-codec: phandle for the SiRF internal codec node

Optional properties:
- hp-pa-gpios: Need to be present if the board need control external
  headphone amplifier.
- spk-pa-gpios: Need to be present if the board need control external
  speaker amplifier.
- hp-switch-gpios: Need to be present if the board capable to detect jack
  insertion, removal.

Available audio endpoints for the audio-routing table:

Board connectors:
 * Headset Stereophone
 * Ext Spk
 * Line In
 * Mic

SiRF internal audio codec pins:
 * HPOUTL
 * HPOUTR
 * SPKOUT
 * Ext Mic
 * Mic Bias

Example:

sound {
		compatible = "sirf,sirf-audio-card";
		sirf,audio-codec = <&audiocodec>;
		sirf,audio-platform = <&audioport>;
		hp-pa-gpios = <&gpio 44 0>;
		spk-pa-gpios = <&gpio 46 0>;
		hp-switch-gpios = <&gpio 45 0>;
};