Re: [PATCH v5 23/32] ASoC: dt-bindings: Add Q6USB backend

[Rob Herring <robh@kernel.org>]

On Tue, Aug 29, 2023 at 02:06:48PM -0700, Wesley Cheng wrote:
> Add a dt-binding to describe the definition of enabling the Q6 USB backend
> device for audio offloading.  The node carries information, which is passed
> along to the QC USB SND class driver counterpart.  These parameters will be
> utilized during QMI stream enable requests.
> 
> Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>
> ---
>  .../bindings/sound/qcom,q6usb-dais.yaml       | 53 +++++++++++++++++++

filename should match the compatible.

>  1 file changed, 53 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/sound/qcom,q6usb-dais.yaml
> 
> diff --git a/Documentation/devicetree/bindings/sound/qcom,q6usb-dais.yaml b/Documentation/devicetree/bindings/sound/qcom,q6usb-dais.yaml
> new file mode 100644
> index 000000000000..72254d7e70d2
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/sound/qcom,q6usb-dais.yaml
> @@ -0,0 +1,53 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/sound/qcom,q6usb-dais.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Qualcomm ASoC DPCM USB backend DAI
> +
> +maintainers:
> +  - Wesley Cheng <quic_wcheng@quicinc.com>
> +
> +description:
> +  The USB port is a supported AFE path on the Q6 DSP.  This ASoC DPCM
> +  backend DAI will communicate the required settings to initialize the
> +  XHCI host controller properly for enabling the offloaded audio stream.
> +  Parameters defined under this node will carry settings, which will be
> +  passed along during the QMI stream enable request and configuration of
> +  the XHCI host controller.
> +
> +allOf:
> +  - $ref: dai-common.yaml#
> +
> +properties:
> +  compatible:
> +    enum:
> +      - qcom,q6usb
> +
> +  iommus:
> +    maxItems: 1
> +
> +  "#sound-dai-cells":
> +    const: 1
> +
> +  qcom,usb-audio-intr-num:
> +    description:
> +      Desired XHCI interrupter number to use.
> +    $ref: /schemas/types.yaml#/definitions/uint32

This is the range as num-hc-interrupters, right?

Perhaps this should also be uint16 and limited to 1024 (or 8).

But why does this need to be in DT? Can't the OS just pick one to 
assign? (the description should answer this)

> +
> +required:
> +  - compatible
> +  - "#sound-dai-cells"
> +  - qcom,usb-audio-intr-num
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    dais {
> +      compatible = "qcom,q6usb";
> +      #sound-dai-cells = <1>;
> +      iommus = <&apps_smmu 0x180f 0x0>;
> +      qcom,usb-audio-intr-num = <2>;
> +    };