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

[Wesley Cheng]

Hi Rob,

On 8/31/2023 10:29 AM, Rob Herring wrote:
> 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@xxxxxxxxxxx>
> > ---
> >   .../bindings/sound/qcom,q6usb-dais.yaml       | 53 +++++++++++++++++++
>
> filename should match the compatible.

Got it.

> >   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@xxxxxxxxxxx>
> > +
> > +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).

True, will change that accordingly.

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

Intention of this is because the user of the secondary interrupter ring 
is listening to a particular event ring.  For example, the audio DSP 
would only work on interrupter ring#2 for SM8350, but can possibly 
differ on other platforms.

Thanks
Wesley Cheng