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

From: Rob Herring
Date: Fri Mar 20 2020 - 13:48:18 EST


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@xxxxxxx>
> ---
> .../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@xxxxxxx>
> +
> +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
>