Re: [PATCH 2/6] ASoC: sun4i-codec: Add playback only flag to quirks

[Andre Przywara <andre.przywara@arm.com>]

On Sun, 20 Oct 2024 19:04:24 +1300
"Ryan Walklin" <ryan@testtoast.com> wrote:

Hi Ryan,

> On Wed, 9 Oct 2024, at 1:32 AM, Andre Przywara wrote:
> 
> Hi Andre, thanks for reviewing! 
> 
> > On Sun, 29 Sep 2024 23:06:03 +1300
> > Ryan Walklin <ryan@testtoast.com> wrote:
> >  
> >> From: Marcus Cooper <codekipper@gmail.com>
> >> 
> >> Some devices only have the playback side of the codec implemented
> >> so add a quirk to check for this.  
> >
> > That's odd, is this really the only place where we need to 
> > consider the lack of sampling functionality? I mean it just prevents the
> > fields to be populated in our internal struct, how does the rest of the
> > kernel know that there is no capture? Is that magically achieved by those
> > fields being zero now?  
> 
> Yes this is only used internally by the codec driver. The playback only nature of an individual codec is communicated to the DAI when the machine driver is created, for example in sun50i_h616_codec_create_card():
> 
> 	card->dai_link->playback_only = true;
> 	card->dai_link->capture_only = false;

Ah, that makes sense indeed, I now see those lines.

Many thanks for the explanation!

Cheers,
Andre