[alsa-devel] [PATCH v2] ASoC: wm8741: Add differential mono mode support

[Charles Keepax]

On Mon, May 11, 2015 at 11:12:00AM +0200, Sergej Sawazki wrote:
> On 11.05.2015 at 10:12, Charles Keepax wrote:
> > On Tue, May 05, 2015 at 10:46:31PM +0200, Sergej Sawazki wrote:
> >> +static int wm8741_add_controls(struct snd_soc_codec *codec)
> >> +{
> >> +	struct wm8741_priv *wm8741 = snd_soc_codec_get_drvdata(codec);
> >> +
> >> +	switch (wm8741->pdata.diff_mode) {
> >> +	case WM8741_DIFF_MODE_STEREO:
> >> +	case WM8741_DIFF_MODE_STEREO_REVERSED:
> >> +		snd_soc_add_codec_controls(codec, wm8741_snd_controls,
> >> +				ARRAY_SIZE(wm8741_snd_controls));
> >> +		break;
> >> +	case WM8741_DIFF_MODE_MONO_LEFT:
> >> +	case WM8741_DIFF_MODE_MONO_RIGHT:
> >> +		/* The machine driver is responsible for mixer controls
> >> +		 * if the codec is configured in differential mono mode.
> >> +		 */
> > Would it not be better to add controls but with a channel neutral
> > name and then the machine driver can use the name_prefix stuff to
> > stick left and right onto them? Seems a bit odd for the machine
> > driver to have to know exact register details of the CODEC and
> > manually add the volume controls?
> >
> > Thanks,
> > Charles
> 
> Charles, could you point me to an "name_prefix" example please?
> 
> Thanks,
> Sergej
> 

The wm9081's handling in sound/soc/samsung/bells.c would be a
reasonable example.

Thanks,
Charles