Re: [PATCH v2 2/2] ASoC: cs35l56: Allow factory calibration through ALSA controls

[Richard Fitzgerald]

On 25/03/2026 5:53 pm, Mark Brown wrote:
> On Wed, Mar 25, 2026 at 05:08:41PM +0000, Richard Fitzgerald wrote:
> > Add support for using ALSA controls to trigger a factory calibration.
> > This is protected by a new Kconfig option so that it is only available
> > if explicitly enabled in the kernel. By default it is not enabled.
>
> > Factory calibration is normally done through debugfs files.
> > Google have requested that factory calibration can be performed by
> > repair shops. These repair shops only have access to the standard
> > "user" kernel, which does not include debugfs.
>
> AFAICT this doesn't have an EFI write command like the debugfs code does
> (when you write "store_uefi").  I don't mind, just wanted to double
> check that this is desirable?

That's correct. The Google devices don't have EFI storage, they will
use the CAL_DATA_RB control to extract the calibration data to save it
in their own persistent storage.