linux-kernel - Re: [PATCH 03/16] ASoC: tas2781: disable regmap regcache

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Date: Fri, 15 Dec 2023 15:42:43 +0100
From: Gergo Koteles <soyer@....hu>
To: Mark Brown <broonie@...nel.org>
Cc: Shenghao Ding <shenghao-ding@...com>, Kevin Lu <kevin-lu@...com>,
  Baojun Xu <baojun.xu@...com>, Jaroslav Kysela <perex@...ex.cz>,
  Takashi Iwai <tiwai@...e.com>, Liam Girdwood <lgirdwood@...il.com>,
  linux-kernel@...r.kernel.org, alsa-devel@...a-project.org
Subject: Re: [PATCH 03/16] ASoC: tas2781: disable regmap regcache

On Fri, 2023-12-15 at 12:55 +0000, Mark Brown wrote:
> On Fri, Dec 15, 2023 at 02:17:01AM +0100, Gergo Koteles wrote:
> > On Thu, 2023-12-07 at 22:39 +0000, Mark Brown wrote:
> > > On Thu, Dec 07, 2023 at 10:12:13PM +0100, Gergo Koteles wrote:
> > > > On Thu, 2023-12-07 at 20:36 +0000, Mark Brown wrote:
> 
> > > > > The code creates the impression that writing to one tas2781 writes to
> > > > > all of them, is that not the case?
> 
> > > > Yes, the tasdevice_* functions, but the regcache_sync doesn't know
> > > > this.
> 
> > > So this syncing is done in software not hardware?  My understanding was
> > > that this was a hardware thing.
> 
> > If you mean that the amplifier does not know that there are several
> > programs or configurations or profiles, but only runs the current one,
> > yes.
> 
> No, I mean that the amplifiers don't talk to each other at a hardware
> level and the grouping is all in software.

No, they don't talk to each other. But they have a global i2c address
to speed up configuration, but the module doesn't use it yet.