[alsa-devel] [RFC PATCH] ASoC: wm8741: Add differential mono mode support

[Sergej Sawazki]

Am 04.05.2015 um 13:25 schrieb Mark Brown:
> On Fri, May 01, 2015 at 08:13:57PM +0200, Sergej Sawazki wrote:
>
>> +static const struct snd_kcontrol_new wm8741_snd_controls_mono_right[] = {
>> +	SOC_SINGLE_TLV("Fine Playback Volume Right", WM8741_DACRLSB_ATTENUATION,
>> +		1, 255, 1, dac_tlv_fine),
>> +	SOC_SINGLE_TLV("Playback Volume Right", WM8741_DACRMSB_ATTENUATION,
>> +		0, 511, 1, dac_tlv),
>> +};
>
> Please follow the control naming standard in ControlNames.txt: all
> volume controls must have Volume as the last word in the name.

Thanks for this information. I would suggest "Right Fine Playback
Volume". Where "Right" is the "CHANNEL" from ControlNames.txt.
However, there is no "Right" in the "CHANNEL" section.
What do you think?

>>   	.name = "wm8741",
>>   	.playback = {
>>   		.stream_name = "Playback",
>> -		.channels_min = 2,  /* Mono modes not yet supported */
>> +		.channels_min = 1,
>>   		.channels_max = 2,
>
> This should be varying with the platform data: in the mono modes we
> can't do stereo and I suspect the stereo modes may have issues with
> mono.

I think this should be always ".channels_min = 2". In "mono mode"
the DAC plays either the right or the left channel, however the I2S
signal is expected to be stereo.

Sergej