Kernel-4.18.0-80.el8_audio-graph-car

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";
                ...
            };
        };
    };
};