ASoC: wm8960: add DAC mono mix kcontrol
In normal operation, the left and right channel digital audio data is
converted to analogue in two separate DACs. There is a mono-mix mode
where the two audio channels are mixed together digitally and then
converted to analogue using only one DAC, while the other DAC is
switched off. The mono-mix signal can be selected to appear on both
analogue output channels. The mono mix is automatically attenuated by
6dB to prevent clipping.
Signed-off-by: Zidan Wang <[email protected]>
Acked-by: Charles Keepax <[email protected]>
Signed-off-by: Mark Brown <[email protected]>