Re: [PATCH v4 10/23] ASoC: simple-card: Wrong daifmt for CPU end of DPCM DAI link

[Sameer Pujar <spujar-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>]

On 6/30/2020 6:26 AM, Kuninori Morimoto wrote:
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>
>
> Hi Sameer
>
>>   snd_soc_runtime_set_dai_fmt() {
>>       ...
>>
>>       if (cpu_dai->component->driver->non_legacy_dai_naming)
>>           fmt = inv_dai_fmt;
>>
>>       ...
>>   }
>>
>> Above flips polarity for 'cpu_dai' if 'non_legacy_dai_naming' flag is set.
>>
>> 1. Hence example mentioned in the commit message does not work if my 'cpu_dai'
>> driver does not have this flag set.
> ?
> Do you want fo flip it ? or don't flip?
> It is for Codec <-> Codec connection.

For DPCM links I don't want to flip based on one Codec reference. My 
goal was to make the binding work for multiple CPU/Codec link. Hence I 
thought it would be better to explicitly describe the 'Master' DAI. We 
can eventually get rid of 'codec' argument from simple_dai_link_of_dpcm().
>> 2. While it is true that we consider reference of 'Codec' mode for simple CPU<->
>> Codec DAI links, for DPCM this does not seem flexible. For DPCM links CPU and
>> Codec are not directly connected (CPU<->Dummy or Dummy<->Codec). Please
>> consider, for example, if the DAI link has multiple CPU/Codecs. Which 'Codec'
>> reference needs to be considered? Isn't it better if we explicitly mention which
>> DAI we want to operate as 'Master'?
> I think Lars-Peter has (had ?) plan for this SND_SOC_DAIFMT_CBx_CFx
> flag flexibility ? Yes maybe it is needed for multi CPU/Codec system.
>
> Thank you for your help !!
>
> Best regards
> ---
> Kuninori Morimoto