[alsa-devel] [PATCH] ASoC: da732x: Mark DC offset control registers volatile

Mark Brown broonie at kernel.org
Mon Feb 24 13:42:30 CET 2014

On Mon, Feb 24, 2014 at 11:31:25AM +0000, Opensource [Adam Thomson] wrote:
> On Mon, 24 Feb 2014 03:01:37 +0000, Mark Brown wrote:

> > but since the registers are marked as volatile and there is a register

> Guessing that should read 'not marked as volatile'.


> Having looked over the driver again, can you include the following
> registers as well: 


I did notice those.  However they are a bit more fun since they have
some non-volatile fields in them which are also used for control.  I
*suspect* that a lot of the time it'll be possible to get away with just
caching the first read but it needs further study - often with these
things the basic offset is constant in a given system so the sign may
well be right all the time.  That's just a guess, though, and may not
actually hold at which point a bit more attention might be needed.

> Also, if we're doing this then you can move to using snd_soc_read()
> instead of hw_read(), I guess.

Indeed, in fact it was while doing an audit of drivers to kill off
direct users of hw_read() that I noticed what was happening here.
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