If we want to use the microphone function of the wm8978 codec, we must enable the microphone bias circuit and power up the bias circuit,otherwise the microphone can not vibrate for sound source sampling.The bit that controls the output voltage of the bias circuit is the fourth bit of the WM8978_POWER_MANAGEMENT_1 register,so this bit must be set to 1.This patch can support the recording function of the wm8978 codec.

Signed-off-by: Mengchen Li mengchenli64@gmail.com --- sound/soc/codecs/wm8978.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/sound/soc/codecs/wm8978.c b/sound/soc/codecs/wm8978.c index a682f80..fdd5429 100644 --- a/sound/soc/codecs/wm8978.c +++ b/sound/soc/codecs/wm8978.c @@ -822,7 +822,9 @@ static int wm8978_hw_params(struct snd_pcm_substream *substream,

snd_soc_component_write(component, WM8978_AUDIO_INTERFACE, iface_ctl); snd_soc_component_write(component, WM8978_ADDITIONAL_CONTROL, add_ctl); - + /* Enable MICBEN */ + snd_soc_component_write(component, WM8978_POWER_MANAGEMENT_1, + snd_soc_component_read(component, WM8978_POWER_MANAGEMENT_1) | 0x10); if (wm8978->sysclk != current_clk_id) { if (wm8978->sysclk == WM8978_PLL) /* Run CODEC from PLL instead of MCLK */