Re: [PATCH v2 09/14] ASoC: audio-graph-card2: add Yaml Document

[Rob Herring <robh@kernel.org>]

On Mon, Jul 19, 2021 at 7:48 PM Kuninori Morimoto
<kuninori.morimoto.gx@renesas.com> wrote:
>
>
> From: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
>
> This patch adds Audio Graph Card2 Yaml bindings.
> It is similar to Audio Graph Card, but different.
>
>         - audio-graph-card  used "dais"  to indicate DAI-links,
>           audio-graph-card2 uses "links" to it.
>
>         - audio-graph-card  used "phandle" to indicate bitclock/frame-master,
>           audio-graph-card2 uses flag to it.
>
>         - audio-graph-card  used "format" to indicate DAI format,
>           audio-graph-card2 assumes CPU/Codec drivers have .get_fmt support.

Why do we need these changes? I'm not wild about a new generic binding
replacing an existing one which only has 2 or 3 users IIRC. Plus
there's already the Renesas variant. (On the flip side, only a few
users, easier to deprecate the old binding.)

I also would like to see the graph card replace the simple card
binding. Surely it can handle the 'simple' case too.

> Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
> ---
>  .../sound/audio-graph-card2-items.yaml        | 80 +++++++++++++++++++
>  .../bindings/sound/audio-graph-card2.yaml     | 51 ++++++++++++
>  2 files changed, 131 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/sound/audio-graph-card2-items.yaml
>  create mode 100644 Documentation/devicetree/bindings/sound/audio-graph-card2.yaml
>
> diff --git a/Documentation/devicetree/bindings/sound/audio-graph-card2-items.yaml b/Documentation/devicetree/bindings/sound/audio-graph-card2-items.yaml
> new file mode 100644
> index 000000000000..ec94cad6b939
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/sound/audio-graph-card2-items.yaml
> @@ -0,0 +1,80 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/sound/audio-graph-card2-items.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Audio Graph Card2 Items Bindings
> +
> +maintainers:
> +  - Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
> +
> +properties:
> +  compatible:
> +    enum:
> +      - audio-graph-card2-dsp
> +      - audio-graph-card2-multi
> +      - audio-graph-card2-codec2codec

This appears to be a significant change. Why do we need to encode this
info into the compatible? Can't walking the graph tell us this info?

> +
> +  "#address-cells":
> +    const: 1
> +
> +  "#size-cells":
> +    const: 0
> +
> +patternProperties:
> +  "^ports(@[0-1])?$":
> +    $ref: /schemas/graph.yaml#/properties/ports
> +    properties:
> +      port(@[0-9a-f]+)?:
> +        $ref: audio-graph-port.yaml#
> +        unevaluatedProperties: false
> +    additionalProperties: true
> +
> +required:
> +  - compatible
> +
> +additionalProperties: true
> +
> +examples:
> +  - |
> +    mix {
> +        compatible = "audio-graph-card2-dsp";
> +
> +        /* sample ports
> +        ports@0 {
> +            port@0 { mix_fe0_ep: endpoint { remote-endpoint = <&cpu0_ep>; }; };
> +            port@1 { mix_fe1_ep: endpoint { remote-endpoint = <&cpu1_ep>; }; };
> +        };
> +        ports@1 {
> +            port@0 { mix_be0_ep: endpoint { remote-endpoint = <&codec0_ep>; }; };
> +        };
> +        */
> +    };
> +
> +    multi {
> +        compatible = "audio-graph-card2-multi";
> +
> +        /* sample ports
> +        ports@0 {
> +            port@0 { multi_00_ep: endpoint { remote-endpoint = <&cpu2_ep>; }; };
> +            port@1 { multi_01_ep: endpoint { remote-endpoint = <&cpu3_ep>; }; };
> +        };
> +        ports@1 {
> +            port@0 { multi_10_ep: endpoint { remote-endpoint = <&codec1_ep>; }; };
> +            port@1 { multi_11_ep: endpoint { remote-endpoint = <&codec2_ep>; }; };
> +        };
> +        */
> +    };
> +
> +    codec2codec {
> +        compatible = "audio-graph-card2-codec2codec";
> +
> +        /* sample ports
> +        rate = <48000>;
> +        ports {
> +            port@0 { c2c_0_ep: endpoint { remote-endpoint = <&codec3_ep>; }; };
> +            port@1 { c2c_1_ep: endpoint { remote-endpoint = <&codec4_ep>; }; };
> +        };
> +        */
> +    };
> diff --git a/Documentation/devicetree/bindings/sound/audio-graph-card2.yaml b/Documentation/devicetree/bindings/sound/audio-graph-card2.yaml
> new file mode 100644
> index 000000000000..4975f88de025
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/sound/audio-graph-card2.yaml
> @@ -0,0 +1,51 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/sound/audio-graph-card2.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Audio Graph Card2 Device Tree Bindings
> +
> +maintainers:
> +  - Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
> +
> +properties:
> +  compatible:
> +    enum:
> +      - audio-graph-card2
> +  links:
> +    $ref: /schemas/types.yaml#/definitions/phandle-array
> +  label:
> +    maxItems: 1
> +  routing:
> +    description: |
> +      A list of the connections between audio components.
> +      Each entry is a pair of strings, the first being the
> +      connection's sink, the second being the connection's source.
> +    $ref: /schemas/types.yaml#/definitions/non-unique-string-array
> +
> +required:
> +  - compatible
> +  - links
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    sound {
> +        compatible = "audio-graph-card2";
> +
> +        links = <&cpu_port>;
> +    };
> +
> +    cpu {
> +        compatible = "cpu-driver";
> +
> +        cpu_port: port { cpu_ep: endpoint { remote-endpoint = <&codec_ep>; }; };
> +    };
> +
> +    codec {
> +        compatible = "codec-driver";
> +
> +        port { codec_ep: endpoint { remote-endpoint = <&cpu_ep>; }; };
> +    };
> --
> 2.25.1
>