WM8991_DAC_CTRL
val = snd_soc_component_read(component, WM8991_DAC_CTRL) & ~WM8991_DAC_MUTE;
snd_soc_component_write(component, WM8991_DAC_CTRL, val | WM8991_DAC_MUTE);
snd_soc_component_write(component, WM8991_DAC_CTRL, val);
val = snd_soc_component_read(component, WM8991_DAC_CTRL);
snd_soc_component_write(component, WM8991_DAC_CTRL, val | WM8991_DAC_MUTE);
regmap_write(wm8991->regmap, WM8991_DAC_CTRL, 0);