[PATCH 4.19 164/219] ASoC: wm8904: fix regcache handling

[Greg Kroah-Hartman]

From: Michael Walle <michael@xxxxxxxx>

[ Upstream commit e9149b8c00d25dbaef1aa174fc604bed207e576d ]

The current code assumes that the power is turned off in
SND_SOC_BIAS_OFF. If there are no actual regulator the codec isn't
turned off and the registers are not reset to their default values but
the regcache is still marked as dirty. Thus a value might not be written
to the hardware if it is set to the default value. Do a software reset
before turning off the power to make sure the registers are always reset
to their default states.

Signed-off-by: Michael Walle <michael@xxxxxxxx>
Acked-by: Charles Keepax <ckeepax@xxxxxxxxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20191112223629.21867-1-michael@xxxxxxxx
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 sound/soc/codecs/wm8904.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/sound/soc/codecs/wm8904.c b/sound/soc/codecs/wm8904.c
index 1965635ec07c..d14e851b9160 100644
--- a/sound/soc/codecs/wm8904.c
+++ b/sound/soc/codecs/wm8904.c
@@ -1902,6 +1902,7 @@ static int wm8904_set_bias_level(struct snd_soc_component *component,
 		snd_soc_component_update_bits(component, WM8904_BIAS_CONTROL_0,
 				    WM8904_BIAS_ENA, 0);
 
+		snd_soc_component_write(component, WM8904_SW_RESET_AND_ID, 0);
 		regcache_cache_only(wm8904->regmap, true);
 		regcache_mark_dirty(wm8904->regmap);
 
-- 
2.20.1