Re: [PATCH v3 20/28] ASoC: dt-bindings: Add Q6USB backend bindings

From: Wesley Cheng <quic_wcheng@quicinc.com>
To: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>,
	<srinivas.kandagatla@linaro.org>, <mathias.nyman@intel.com>,
	<perex@perex.cz>, <broonie@kernel.org>, <lgirdwood@gmail.com>,
	<krzysztof.kozlowski+dt@linaro.org>, <agross@kernel.org>,
	<Thinh.Nguyen@synopsys.com>, <bgoswami@quicinc.com>,
	<andersson@kernel.org>, <robh+dt@kernel.org>,
	<gregkh@linuxfoundation.org>, <tiwai@suse.com>
Cc: <linux-kernel@vger.kernel.org>, <linux-arm-msm@vger.kernel.org>,
	<alsa-devel@alsa-project.org>, <devicetree@vger.kernel.org>,
	<linux-usb@vger.kernel.org>, <quic_jackp@quicinc.com>,
	<quic_plai@quicinc.com>
Subject: Re: [PATCH v3 20/28] ASoC: dt-bindings: Add Q6USB backend bindings
Date: Thu, 22 Jun 2023 17:15:20 -0700	[thread overview]
Message-ID: <82734575-4dc4-b65b-533b-6a7d7eebacc9@quicinc.com> (raw)
In-Reply-To: <499ee440-0c52-bb21-d04d-086aebc0cf4e@linaro.org>

Hi Krzysztof,

On 3/10/2023 12:54 AM, Krzysztof Kozlowski wrote:
> On 09/03/2023 00:57, 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       | 49 +++++++++++++++++++
>>   1 file changed, 49 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..8477abc511dd
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/sound/qcom,q6usb-dais.yaml
>> @@ -0,0 +1,49 @@
>> +# 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 USB backend DAI
>> +
>> +maintainers:
>> +  - Wesley Cheng <quic_wcheng@quicinc.com>
>> +
>> +description:
>> +  The Q6USB backend is a supported AFE port on the Q6DSP. This backend
>> +  driver will communicate the required settings to the QC USB SND class
> 
> What does the "driver" mean? Linux driver? Then drop and focus on
> hardware/Q6DSP.
> 

Sorry for the late reply, was side tracked on some other priorities, and 
reviving this series again.

The driver here is a Linux ASoC based DPCM backend driver, which will 
interface with the CPU dai (q6afe).

>> +  driver for properly enabling the audio stream.  Parameters defined
>> +  under this node will carry settings, which will be passed along during
>> +  the QMI stream enable request.
>> +
>> +properties:
>> +  compatible:
>> +    enum:
>> +      - qcom,q6usb-dais
> 
> Can q6usb mean anything else? Why "-dais" suffix?
> 

As of now, no...will remove the dai suffix.

>> +
>> +  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
> 
> Why this should be configurable per board or SoC? It's the first use in
> DT and in the same time sounds generic...
> 

Would depend on which interrupter we want to use.  This should be 
configurable per platform in case the audio DSP decides to work off a 
specific interrupter.

Thanks
Wesley Cheng

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