Re: [PATCHv4 9/9] ASoC: dt-bindings: fsl-asoc-card: add compatible for generic codec

Rob Herring
2024-05-20T18:31:50Z

On Wed, May 15, 2024 at 03:54:11PM +0200, Elinor Montmasson wrote:
> Add documentation about new dts bindings following new support
> for compatible "fsl,imx-audio-generic".
>
> Some CPU DAI don't require a real audio codec. The new compatible
> "fsl,imx-audio-generic" allows using the driver with codec drivers
> SPDIF DIT and SPDIF DIR as dummy codecs.
> It also allows using not pre-configured audio codecs which
> don't require specific control through a codec driver.
>
> The new dts properties give the possibility to set some parameters
> about the CPU DAI usually set through the codec configuration.
>
> Signed-off-by: Elinor Montmasson <elinor.montmasson@savoirfairelinux.com>
> ---
> .../bindings/sound/fsl-asoc-card.yaml | 96 ++++++++++++++++++-
> 1 file changed, 92 insertions(+), 4 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/sound/fsl-asoc-card.yaml b/Documentation/devicetree/bindings/sound/fsl-asoc-card.yaml
> index 9922664d5ccc..332d8bf96e06 100644
> --- a/Documentation/devicetree/bindings/sound/fsl-asoc-card.yaml
> +++ b/Documentation/devicetree/bindings/sound/fsl-asoc-card.yaml
> @@ -23,6 +23,16 @@ description:
> and PCM DAI formats. However, it'll be also possible to support those non
> AC'97/I2S/PCM type sound cards, such as S/PDIF audio and HDMI audio, as
> long as the driver has been properly upgraded.
> + To use CPU DAIs that do not require a codec such as an S/PDIF controller,
> + or to use a DAI to output or capture raw I2S/TDM data, you can
> + use the compatible "fsl,imx-audio-generic".
> +
> +definitions:
> + imx-audio-generic-dependency:
> + properties:
> + compatible:
> + contains:
> + const: fsl,imx-audio-generic
>
> maintainers:
> - Shengjiu Wang <shengjiu.wang@nxp.com>
> @@ -81,6 +91,7 @@ properties:
> - fsl,imx-audio-wm8960
> - fsl,imx-audio-wm8962
> - fsl,imx-audio-wm8958
> + - fsl,imx-audio-generic
>
> model:
> $ref: /schemas/types.yaml#/definitions/string
> @@ -93,8 +104,14 @@ properties:
> need to add ASRC support via DPCM.
>
> audio-codec:
> - $ref: /schemas/types.yaml#/definitions/phandle
> - description: The phandle of an audio codec
> + $ref: /schemas/types.yaml#/definitions/phandle-array
> + description: |
> + The phandle of an audio codec.
> + If using the "fsl,imx-audio-generic" compatible, give instead a pair of
> + phandles with the spdif_transmitter first (driver SPDIF DIT) and the
> + spdif_receiver second (driver SPDIF DIR).

minItems: 1
maxItems: 2

> + items:
> + maxItems: 1
>
> audio-cpu:
> $ref: /schemas/types.yaml#/definitions/phandle
> @@ -150,8 +167,8 @@ properties:
> description: dai-link uses bit clock inversion.
>
> mclk-id:
> - $ref: /schemas/types.yaml#/definitions/uint32
> - description: main clock id, specific for each card configuration.
> + $ref: /schemas/types.yaml#/definitions/uint32-array
> + description: Main clock id for each codec, specific for each card configuration.

minItems: 1
maxItems: 2
>
> mux-int-port:
> $ref: /schemas/types.yaml#/definitions/uint32
> @@ -167,10 +184,68 @@ properties:
> $ref: /schemas/types.yaml#/definitions/phandle
> description: The phandle of an CPU DAI controller
>
> + # Properties relevant only with "fsl,imx-audio-generic" compatible
> + dai-tdm-slot-width:
> + description: See tdm-slot.txt.
> + $ref: /schemas/types.yaml#/definitions/uint32
> +
> + dai-tdm-slot-num:
> + description: See tdm-slot.txt.
> + $ref: /schemas/types.yaml#/definitions/uint32
> +
> + clocks:
> + description: |
> + The CPU DAI system clock, used to retrieve
> + the CPU DAI system clock frequency with the generic codec.
> + maxItems: 1
> +
> + clock-names:
> + items:
> + - const: cpu_sysclk
> +
> + cpu-system-clock-direction-out:
> + description: |
> + Specifies cpu system clock direction as 'out' on initialization.
> + If not set, direction is 'in'.
> + $ref: /schemas/types.yaml#/definitions/flag
> +
> +dependencies:
> + dai-tdm-slot-width:
> + $ref: "#/definitions/imx-audio-generic-dependency"
> + dai-tdm-slot-num:
> + $ref: "#/definitions/imx-audio-generic-dependency"
> + clocks:
> + $ref: "#/definitions/imx-audio-generic-dependency"
> + cpu-system-clock-direction-out:
> + $ref: "#/definitions/imx-audio-generic-dependency"

This works, but is an unusual pattern...

> +
> required:
> - compatible
> - model
>
> +allOf:
> + - if:
> + $ref: "#/definitions/imx-audio-generic-dependency"
> + then:
> + properties:
> + audio-codec:
> + items:
> + - description: SPDIF DIT phandle
> + - description: SPDIF DIR phandle
> + mclk-id:
> + maxItems: 1
> + items:
> + minItems: 1
> + maxItems: 2
> + else:
> + properties:
> + audio-codec:
> + maxItems: 1
> + mclk-id:
> + maxItems: 1
> + items:
> + maxItems: 1

You can handle the dependency like this instead:

dai-tdm-slot-width: false
dai-tdm-slot-num: false

And then you don't need the definitions.

> +
> unevaluatedProperties: false
>
> examples:
> @@ -195,3 +270,16 @@ examples:
> "AIN2L", "Line In Jack",
> "AIN2R", "Line In Jack";
> };
> +
> + - |
> + #include <dt-bindings/clock/imx8mn-clock.h>
> + sound-spdif-asrc {
> + compatible = "fsl,imx-audio-generic";
> + model = "spdif-asrc-audio";
> + audio-cpu = <&spdif>;
> + audio-asrc = <&easrc>;
> + audio-codec = <&spdifdit>, <&spdifdir>;
> + clocks = <&clk IMX8MN_CLK_SAI5_ROOT>;
> + clock-names = "cpu_sysclk";
> + cpu-system-clock-direction-out;
> + };
> --
> 2.34.1
>