Re: [alsa-devel] [PATCH] ASoC: sgtl5000: only check VDDD-supply, not revision
From: Fabio Estevam
Date: Sun Jun 05 2016 - 21:23:13 EST
On Sun, Jun 5, 2016 at 8:16 PM, Clemens Gruber
> I looked into this today and discovered the following:
> With my patch applied, if I reset the board just after playback, at the
> next boot, the sgtl5000_fill_defaults function does not succeed: Writing
> the default value 0x7060 to register 0x30 (CHIP_ANA_POWER) fails.
> How did CHIP_ANA_POWER change with my patch: Before, only
> LINREG_SIMPLE_POWERUP was cleared as is recommended in the datasheet
> when using the internal LDO, now both LINREG_SIMPLE_POWERUP and
> STARTUP_POWERUP are cleared, as is recommended when using external VDDD.
> But why does the SGTL5000 nack that default write to CHIP_ANA_POWER
> after a reboot, which interrupted the playback?
> The following patch from Eric solved the problem; one write fails but it
> continues setting the other registers and thus even if resetting a board
> during playback, the sound still works after reboot:
> Another workaround might be to not even write a default value to
> CHIP_ANA_POWER, as in this patch from Eric:
> What do you think we should do?
Shouldn't both patches be applied?