ubuntu-linux-kernel/Documentation/devicetree/bindings/sound/audio-graph-card.txt

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Audio Graph Card:
Audio Graph Card specifies audio DAI connections of SoC <-> codec.
It is based on common bindings for device graphs.
see ${LINUX}/Documentation/devicetree/bindings/graph.txt
Basically, Audio Graph Card property is same as Simple Card.
see ${LINUX}/Documentation/devicetree/bindings/sound/simple-card.txt
Below are same as Simple-Card.
- label
- widgets
- routing
- dai-format
- frame-master
- bitclock-master
- bitclock-inversion
- frame-inversion
- mclk-fs
- dai-tdm-slot-num
- dai-tdm-slot-width
- clocks / system-clock-frequency
Required properties:
- compatible : "audio-graph-card";
- dais : list of CPU DAI port{s}
Optional properties:
- pa-gpios: GPIO used to control external amplifier.
Example: Single DAI case
sound_card {
compatible = "audio-graph-card";
dais = <&cpu_port>;
};
dai-controller {
...
cpu_port: port {
cpu_endpoint: endpoint {
remote-endpoint = <&codec_endpoint>;
dai-format = "left_j";
...
};
};
};
audio-codec {
...
port {
codec_endpoint: endpoint {
remote-endpoint = <&cpu_endpoint>;
};
};
};
Example: Multi DAI case
sound-card {
compatible = "audio-graph-card";
label = "sound-card";
dais = <&cpu_port0
&cpu_port1
&cpu_port2>;
};
audio-codec@0 {
...
port {
codec0_endpoint: endpoint {
remote-endpoint = <&cpu_endpoint0>;
};
};
};
audio-codec@1 {
...
port {
codec1_endpoint: endpoint {
remote-endpoint = <&cpu_endpoint1>;
};
};
};
audio-codec@2 {
...
port {
codec2_endpoint: endpoint {
remote-endpoint = <&cpu_endpoint2>;
};
};
};
dai-controller {
...
ports {
cpu_port0: port@0 {
cpu_endpoint0: endpoint {
remote-endpoint = <&codec0_endpoint>;
dai-format = "left_j";
...
};
};
cpu_port1: port@1 {
cpu_endpoint1: endpoint {
remote-endpoint = <&codec1_endpoint>;
dai-format = "i2s";
...
};
};
cpu_port2: port@2 {
cpu_endpoint2: endpoint {
remote-endpoint = <&codec2_endpoint>;
dai-format = "i2s";
...
};
};
};
};