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ASoC: ssm4567: Reset device before regcache_sync()

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When the ssm4567 is powered up the driver calles regcache_sync() to restore
the register map content. regcache_sync() assumes that the device is in its
power-on reset state. Make sure that this is the case by explicitly
resetting the ssm4567 register map before calling regcache_sync() otherwise
we might end up with a incorrect register map which leads to undefined
behaviour.

One such undefined behaviour was observed when returning from system
suspend while a playback stream is active, in that case the ssm4567 was
kept muted after resume.

Fixes: 1ee44ce030 ("ASoC: ssm4567: Add driver for Analog Devices SSM4567 amplifier")
Reported-by: Harsha Priya <harshapriya.n@intel.com>
Tested-by: Fang, Yang A <yang.a.fang@intel.com>
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Lars-Peter Clausen 2016-01-27 14:26:18 +01:00 committed by Mark Brown
parent 92e963f50f
commit 712a8038cc
1 changed files with 5 additions and 0 deletions
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5
sound/soc/codecs/ssm4567.c
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@ -352,6 +352,11 @@ static int ssm4567_set_power(struct ssm4567 *ssm4567, bool enable)
regcache_cache_only(ssm4567->regmap, !enable);
if (enable) {
ret = regmap_write(ssm4567->regmap, SSM4567_REG_SOFT_RESET,
0x00);
if (ret)
return ret;
ret = regmap_update_bits(ssm4567->regmap,
SSM4567_REG_POWER_CTRL,
SSM4567_POWER_SPWDN, 0x00);