4.5-stable review patch. If anyone has any objections, please let me know.
------------------ From: Lars-Peter Clausen <l...@metafoo.de> commit 712a8038cc24dba668afe82f0413714ca87184e0 upstream. 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: 1ee44ce03011 ("ASoC: ssm4567: Add driver for Analog Devices SSM4567 amplifier") Reported-by: Harsha Priya <harshapriy...@intel.com> Tested-by: Fang, Yang A <yang.a.f...@intel.com> Signed-off-by: Lars-Peter Clausen <l...@metafoo.de> Signed-off-by: Mark Brown <broo...@kernel.org> Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org> --- sound/soc/codecs/ssm4567.c | 5 +++++ 1 file changed, 5 insertions(+) --- a/sound/soc/codecs/ssm4567.c +++ b/sound/soc/codecs/ssm4567.c @@ -352,6 +352,11 @@ static int ssm4567_set_power(struct ssm4 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);