[PATCH] ASoC: tlv320adc3xxx: Add IIR filter configuration

[Ricard Wanderlof]

On Wed, 9 Feb 2022, Mark Brown wrote:

> > In this case it was the ADAU1761 driver and it was several years ago
> > and I don't know if it still is an issue. Basically the sequence was 
> > something like:
> 
> > - System boots up.
> > - Codec is configured (I think it was the sample rate, but it could have 
> >   been the format or some other I2S parameter) to something that is non 
> >   default.
> > - System reboots. Since the codec has no means of getting reset, it
> >   retains all its register values.
> > - This time, an attempt is made to configure the codec with the default
> >   sample rate. Since the driver believes the default is already set
> >   it does not attempt to write anything, although looking at 
> >   regmap_write() now I'm not sure how this could be the case.
> 
> update_bits() could also trigger this if it thinks the value didn't
> change, but that's at a higher level before it ever gets as far as
> trying to do the write and unrelated to the cache (it will also
> suppress redundant writes with no cache present).

Right, that sound even more familiar.

/Ricard
-- 
Ricard Wolf Wanderlof                           ricardw(at)axis.com
Axis Communications AB, Lund, Sweden            www.axis.com
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