[alsa-devel] [PATCH 2/3] ASoC: wm8741: Set OSR mode in hw_params()

[Sergej Sawazki]

Am 05.09.2017 um 18:12 schrieb Charles Keepax:
> On Mon, Sep 04, 2017 at 09:34:12PM +0200, Sergej Sawazki wrote:
>> +	/* oversampling rate */
>> +	if (params_rate(params) > 96000)
>> +		mode |= 0x0040;
>> +	else if (params_rate(params) > 48000)
>> +		mode |= 0x0020;
> 
> Should this not have a case for <= 48k as well? To reset the mode
> if it was set on a previous playback.
> 

It is reset in here:

     u16 mode = snd_soc_read(codec, WM8741_MODE_CONTROL_1) & 0x183;

For <= 48k we simply leave it 0. I though about an empty else statement, 
but it is kind of strange, too.

>> +
>>   	/* bit size */
>>   	switch (params_width(params)) {
>>   	case 16:
>> @@ -243,6 +250,7 @@ static int wm8741_hw_params(struct snd_pcm_substream *substream,
>>   		params_width(params), params_rate(params));
>>   
>>   	snd_soc_write(codec, WM8741_FORMAT_CONTROL, iface);
>> +	snd_soc_write(codec, WM8741_MODE_CONTROL_1, mode);
> 
> Better to use an update_bits rather than basically open-code it
> with read and then this write.
> 

I have used write() and not update_bits() here to be consistent with the 
way the WM8741_FORMAT_CONTROL register is written. If we change it to 
update_bits(), we should refactor the WM8741_FORMAT_CONTROL write to use 
update_bits() too, right?

Thanks,
Sergej