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

[Sameer Pujar]

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