[PATCH] ASoC: pcm512x: Mend accesses to the I2S_1 and I2S_2 registers

[Peter Rosin]

>> Can you try the attached patch w/o without the defaults for i2s_1/2?
>> Not even compile tested...
> 
> [added a couple of underscores]
> 
> I get this early during boot/probe
> [    1.506291] pcm512x 0-004c: pcm512x_set_fmt: failed to read I2S_1: -16
> [    1.512905] pcm512x 0-004c: pcm512x_set_fmt: failed to read PLL_EN: -16
> [    1.519517] pcm512x 0-004c: Failed to set data format: -16
> [    1.525045] pcm512x 0-004c: Failed to set data offset: -16
> 
> and then this later, triggered from userspace when an app opens
> the device
> [   14.620344] pcm512x 0-004c: pcm512x_hw_params: I2S_1: 0x2
> 
> So, reading *can* work.

I added some traces and verified that accesses to I2S_1/2 fail (as do
PLL_EN accesses) when the chip is in Powerdown mode (pcm512x_suspend
has set the RQPD bit in the POWER register), which it is when
pcm512x_set_fmt runs. During pcm512x_hw_params the chip is in Standby
mode instead (pcm512x_resume has cleared the RQPD bit, but the RQST
bit is set).

So, my patch seems wrong, and the I2S_1/2 accesses instead need to
move to some point where the chip is not in Powerdown mode.

Or, is the problem that pcm512x_set_fmt is called while the codec is
suspended and the chip thus is in Powerdown mode? Because, that
seems problematic to me?

Cheers,
Peter