[alsa-devel] [PATCH] ASoC: fsl_esai: Clear the xPM bit when using xFP

[Marek Vasut]

On 04/08/2018 06:01 AM, Nicolin Chen wrote:
> On Sun, Apr 08, 2018 at 04:16:39AM +0200, Marek Vasut wrote:
> 
>>> Could you please provide a failed
>>> instance? It's been a while since I wrote the code. But I can tell
>>> that PM is supposed to be called by set_sysclk() only, while FP is
>>> used for bclk. If you clear PM when setting FP, the output of HCK
>>> could be messed.
>>
>> Try feeding it the following values, The codec I use is PCM1808.
> 
>> [1] fsl_esai_set_dai_sysclk[227] clk_id=0 freq=24576000 dir=1
>> [2] fsl_esai_divisor_cal[131] tx=0 ratio=2 usefp=0 fp=0
>> [3] fsl_esai_set_bclk[322] tx=0 freq=3072000
>> [4] fsl_esai_divisor_cal[131] tx=0 ratio=8 usefp=1 fp=8

Sorry for confusing you, clk_id in [1] should be 3 .
[...]
>> Also, I think there is another bug in the fsl_esai_divisor_cal() now
>> that I look at it.
> 
>> If usefp = 0, then maxfp = 1 , then savesub = 0 and
> 
> I see. This actually would happen when PSR=0. And the ratio in
> this case is <= 256 (which could be satisfied by PM only). Btw,
> is this the reason why you got a "dirty" PM?
> 
> Anyway, this part is a bug. Would you like to fix it?

Clearly I'm getting a bit lost on this convoluted clock calculation.
What is the code trying so elaborately to come up with, ideal
configuration for each of the clock ?

-- 
Best regards,
Marek Vasut