Re: [PATCH v5 6/7] ASoC: dt-bindings: fsl_easrc: Add document for EASRC

[Rob Herring <robh@kernel.org>]

On Mon, Mar 09, 2020 at 11:58:33AM +0800, Shengjiu Wang wrote:
> EASRC (Enhanced Asynchronous Sample Rate Converter) is a new
> IP module found on i.MX8MN.
> 
> Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
> ---
>  .../devicetree/bindings/sound/fsl,easrc.yaml  | 101 ++++++++++++++++++
>  1 file changed, 101 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/sound/fsl,easrc.yaml
> 
> diff --git a/Documentation/devicetree/bindings/sound/fsl,easrc.yaml b/Documentation/devicetree/bindings/sound/fsl,easrc.yaml
> new file mode 100644
> index 000000000000..ff22f8056a63
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/sound/fsl,easrc.yaml
> @@ -0,0 +1,101 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/sound/fsl,easrc.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: NXP Asynchronous Sample Rate Converter (ASRC) Controller
> +
> +maintainers:
> +  - Shengjiu Wang <shengjiu.wang@nxp.com>
> +
> +properties:
> +  $nodename:
> +    pattern: "^easrc@.*"
> +
> +  compatible:
> +    const: fsl,imx8mn-easrc
> +
> +  reg:
> +    maxItems: 1
> +
> +  interrupts:
> +    maxItems: 1
> +
> +  clocks:
> +    items:
> +      - description: Peripheral clock
> +
> +  clock-names:
> +    items:
> +      - const: mem
> +
> +  dmas:
> +    maxItems: 8
> +
> +  dma-names:
> +    items:
> +      - const: ctx0_rx
> +      - const: ctx0_tx
> +      - const: ctx1_rx
> +      - const: ctx1_tx
> +      - const: ctx2_rx
> +      - const: ctx2_tx
> +      - const: ctx3_rx
> +      - const: ctx3_tx
> +
> +  fsl,easrc-ram-script-name:

'firmware-name' is the established property name for this.

> +    allOf:
> +      - $ref: /schemas/types.yaml#/definitions/string
> +      - const: imx/easrc/easrc-imx8mn.bin

Though if there's only 1 possible value, why does this need to be in DT?

> +    description: The coefficient table for the filters

If the firmware is only 1 thing, then perhaps this should just be a DT 
property rather than a separate file. It depends on who owns/creates 
this file. If fixed for the platform, then DT is a good fit. If updated 
separately from DT and boot firmware, then keeping it separate makes 
sense.

> +
> +  fsl,asrc-rate:
> +    allOf:
> +      - $ref: /schemas/types.yaml#/definitions/uint32
> +      - minimum: 8000
> +      - maximum: 192000
> +    description: Defines a mutual sample rate used by DPCM Back Ends
> +
> +  fsl,asrc-format:
> +    allOf:
> +      - $ref: /schemas/types.yaml#/definitions/uint32
> +      - enum: [2, 6, 10, 32, 36]
> +        default: 2
> +    description:
> +      Defines a mutual sample format used by DPCM Back Ends
> +
> +required:
> +  - compatible
> +  - reg
> +  - interrupts
> +  - clocks
> +  - clock-names
> +  - dmas
> +  - dma-names
> +  - fsl,easrc-ram-script-name
> +  - fsl,asrc-rate
> +  - fsl,asrc-format
> +
> +examples:
> +  - |
> +    #include <dt-bindings/clock/imx8mn-clock.h>
> +
> +    easrc: easrc@300C0000 {
> +           compatible = "fsl,imx8mn-easrc";
> +           reg = <0x0 0x300C0000 0x0 0x10000>;
> +           interrupts = <0x0 122 0x4>;
> +           clocks = <&clk IMX8MN_CLK_ASRC_ROOT>;
> +           clock-names = "mem";
> +           dmas = <&sdma2 16 23 0> , <&sdma2 17 23 0>,
> +                  <&sdma2 18 23 0> , <&sdma2 19 23 0>,
> +                  <&sdma2 20 23 0> , <&sdma2 21 23 0>,
> +                  <&sdma2 22 23 0> , <&sdma2 23 23 0>;
> +           dma-names = "ctx0_rx", "ctx0_tx",
> +                       "ctx1_rx", "ctx1_tx",
> +                       "ctx2_rx", "ctx2_tx",
> +                       "ctx3_rx", "ctx3_tx";
> +           fsl,easrc-ram-script-name = "imx/easrc/easrc-imx8mn.bin";
> +           fsl,asrc-rate  = <8000>;
> +           fsl,asrc-format = <2>;
> +    };
> -- 
> 2.21.0
>