[PATCH 6/6] ASoC: audio-graph: remove Platform support

[Kuninori Morimoto]

Hi Olivier

Thank you for conntacting me

> I have seen that the STM32MP15 audio sound card is no more functional
> with recent kernels (5.13 or 5.14)
> The sound card is registered, but the all devices are issuing an error
> at runtime. These devices are using stm32_sai.c or stm32_i2s.c
> drivers.
> 
> I found that the regression is linked to the commit
> 63f2f9cceb09f8e5f668e36c1cf764eea468ebed "ASoC: audio-graph: remove
> Platform support", as reverting this commit fixes the issue.
> 
> When the platform component is missing the pcm_construct ops in the
> pcm dmaengine, is never called, resulting in an incomplete
> initialization of the sound card.
> I can't figure out what is the right way to handle this change, however.
> Do I need to update the CPU drivers to work without a platform component
> or does the audio-graph card has to be changed in some way ?

Ahh, OK, I see.
Indeed the dev which is used for CPU is used at soc-generic-dmaengine as Platform,
without indicating it at DT (= simple-card has "plat" support for platform at DT,
but audio-graph doesn't ).

I think key funciton is asoc_simple_canonicalize_platform().

> What do you mean "We can respawn it when we need it", in the commit
> message ?

This means we can revert this patch if needed, and yes it is needed :)
Could you please respawn the feature ? or I can do it if you want.

Thank you for your help !!

Best regards
---
Kuninori Morimoto