ASoC: Manage VMID mode for WM8990

A small additional power saving can be achieved for the WM8990 by
maintaining VMID using a 2*250k divider when in standby mode.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/sound/soc/codecs/wm8990.c b/sound/soc/codecs/wm8990.c
index 938e15429207..2d7b0096d929 100644
--- a/sound/soc/codecs/wm8990.c
+++ b/sound/soc/codecs/wm8990.c
@@ -1222,8 +1222,14 @@ static int wm8990_set_bias_level(struct snd_soc_codec *codec,
         switch (level) {
         case SND_SOC_BIAS_ON:
                 break;
+
         case SND_SOC_BIAS_PREPARE:
+                /* VMID=2*50k */
+                val = wm8990_read_reg_cache(codec, WM8990_POWER_MANAGEMENT_1) &
+                        ~WM8990_VMID_MODE_MASK;
+                wm8990_write(codec, WM8990_POWER_MANAGEMENT_1, val | 0x2);
                 break;
+
         case SND_SOC_BIAS_STANDBY:
                 if (codec->bias_level == SND_SOC_BIAS_OFF) {
                         /* Enable all output discharge bits */
@@ -1278,6 +1284,11 @@ static int wm8990_set_bias_level(struct snd_soc_codec *codec,
                         wm8990_write(codec, WM8990_EXT_CTL1, 0xa003);
                         wm8990_write(codec, WM8990_EXT_ACCESS_ENA, 0);
                 }
+
+                /* VMID=2*250k */
+                val = wm8990_read_reg_cache(codec, WM8990_POWER_MANAGEMENT_1) &
+                        ~WM8990_VMID_MODE_MASK;
+                wm8990_write(codec, WM8990_POWER_MANAGEMENT_1, val | 0x4);
                 break;
 
         case SND_SOC_BIAS_OFF: