On Wed, Jun 23, 2021 at 12:10:53AM +0800, Judy Hsiao wrote:

> Thanks for your review comment.
> This patch is used to support multi-channel where we want one codec to
> control the only GPIO shared by 4 amps.

So you've got 4 instances of the same CODEC?  Then I'd expect to see
those all individually represented in DT.  Or if there's a single
physical CODEC then I'm not sure what the dummies are for?

> In snd_soc_runtime_calc_hw(), by creating dummy codecs that share a
> DAI link with a real codec:
>   1. The min/ max channel of  CPU DAI will be directly adopted.
>   2. The formats and sample rates of the DAI link will be determined
> by the real codec unless the real codec supports the rate
>       and format that do not intersect with the rate and format of
> snd-soc-dummy.
> That is the reason why we don’t specify the format and sample rates of
> the dummy codec with the real codec determining the properties .

It's not clear to me why you'd not just describe the actual CODECs here
rather than using a dummy CODEC, the fact that the dummy CODEC is doing
what you want is just an accident of the implementation rather than a
description of the hardware.