Re: [PATCH 5/5] ASoC: rsnd: dma: use extended audio dmac registers when available

[Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>]

Hi Geert

> > I can agree to have both basic/extend register
> > if driver need to switch its behavior.
> > But this case, there is nothing to do on driver side.
> > In other words, SoC always need to use extend
> > register if it has.
> > I don't know why datasheet is indicating both area.
> > Maybe it is because for Gen3 all-in ? I'm not sure.
> >
> > Anyway, Simon, can you agree about it ?
> > Having both basic/extend register is just noise for driver.
> 
> I can follow your rationale of only describing the extended register set,
> if available.

Thank you

> However:
>   1) The DT bindings should state clearly that the AUDMAPP register
>      block should point to the extended register set, if available,

Yes, indeed.
I re-used your sample patch, and posted.

>   2) Can the driver distinguish between an old DTB describing the basic
>      register set, and a new DTB describing the extended register set?
>      I.e. will the driver avoid using busif4-7 when using an old DTB
>      describing the basic register set, to maintain backwards compatibility?

The situation which need to use busif4-7 is
TDM 16ch Split mode. It is very rare case.
And it is not yet supported on driver.
This means, there is zero chance to access to busif4-7 under old DTB.

Best regards
---
Kuninori Morimoto