linux-kernel - [PATCH] ASoC: wm8904: fix regcache handling

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Message-Id: <20191112223629.21867-1-michael@walle.cc>
Date:   Tue, 12 Nov 2019 23:36:29 +0100
From:   Michael Walle <michael@...le.cc>
To:     alsa-devel@...a-project.org, linux-kernel@...r.kernel.org
Cc:     Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>,
        Jaroslav Kysela <perex@...ex.cz>,
        Takashi Iwai <tiwai@...e.com>, patches@...nsource.cirrus.com,
        Michael Walle <michael@...le.cc>
Subject: [PATCH] ASoC: wm8904: fix regcache handling

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@...le.cc>
---
 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 2a7d23a5daa8..7d7ea15d73e0 100644
--- a/sound/soc/codecs/wm8904.c
+++ b/sound/soc/codecs/wm8904.c
@@ -1933,6 +1933,7 @@ 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