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SubjectRe: [Patch V7 02/10] ASoC: qcom: Document LPASS CPU bindings
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On Mar 5, 2015, at 7:51 PM, Kenneth Westfield <kwestfie@codeaurora.org> wrote:

> On Thu, Mar 05, 2015 at 12:52:30PM -0600, Kumar Gala wrote:
>>
>> On Mar 3, 2015, at 6:21 PM, Kenneth Westfield <kwestfie@codeaurora.org> wrote:
>>
>>> +++ b/Documentation/devicetree/bindings/sound/qcom,lpass-cpu.txt
>>> @@ -0,0 +1,49 @@
>>> +* Qualcomm Technologies LPASS CPU DAI
>>> +
>>> +Required subnodes:
>>> +
>>> +- qcom,adsp : Audio DSP sub-node
>>> +
>>> +Optional Audio DSP subnode properties:
>>> +
>>> +- status : "disabled" indicates the adsp is not available.
>>> +
>>
>> What is the intent of this subnode?
>>
>
> From the cover letter:
> Even though the ipq806x LPASS does not contain an audio DSP, other SOCs
> do have one. For those SOCs, the audio DSP typically controls the
> hardware blocks in the LPASS. Hence, different CPU DAI driver(s) would
> need to be used in order to facilitate audio with the DSP. As such, the
> LPASS DT contains an adsp subnode, which is disabled for this SOC. The
> same subnode should be enabled and populated for other SOCs that do
> contain an audio DSP. Not using the audio DSP would require different
> CPU DAI driver(s), in addition to possible bootloader and/or firmware
> changes.
>
> This was the result of a request from Mark. See here:
> http://thread.gmane.org/gmane.linux.drivers.devicetree/109331/focus=11633

Two quick comments before I read Mark’s comments.

1. Its not normal practice to put something into a DT that does not exist. Having a node, but marking it disabled implies existence.
2. How would one normally address the audio DSP if it did exist. I’m just wondering if having a subnode is the proper solution vs maybe a phandle

- k
--
Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project



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