From 3acef6854c440b29f20d7ea0ec5f4707aad23923 Mon Sep 17 00:00:00 2001 From: Peter Ujfalusi Date: Thu, 22 Sep 2011 11:05:45 +0300 Subject: [PATCH] ASoC: twl6040: Lower the power on gain values at startup The default gains on outputs/inputs are set to 0dB. This is fixing the pop noise issue at the first playback, which caused by the wrong starting point of the ramp code. The ramp code for the outputs expects the gains to be in their lowest configuration in order to be effective. After the playback stops, the ramp code takes care of ramping down the gains to their minimum. Signed-off-by: Peter Ujfalusi Acked-by: Liam Girdwood Signed-off-by: Mark Brown --- sound/soc/codecs/twl6040.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/sound/soc/codecs/twl6040.c b/sound/soc/codecs/twl6040.c index 81645c632447..0694d65f9de3 100644 --- a/sound/soc/codecs/twl6040.c +++ b/sound/soc/codecs/twl6040.c @@ -269,6 +269,17 @@ static void twl6040_init_chip(struct snd_soc_codec *codec) /* No imput selected for microphone amplifiers */ twl6040_write_reg_cache(codec, TWL6040_REG_MICLCTL, 0x18); twl6040_write_reg_cache(codec, TWL6040_REG_MICRCTL, 0x18); + + /* + * We need to lower the default gain values, so the ramp code + * can work correctly for the first playback. + * This reduces the pop noise heard at the first playback. + */ + twl6040_write_reg_cache(codec, TWL6040_REG_HSGAIN, 0xff); + twl6040_write_reg_cache(codec, TWL6040_REG_EARCTL, 0x1e); + twl6040_write_reg_cache(codec, TWL6040_REG_HFLGAIN, 0x1d); + twl6040_write_reg_cache(codec, TWL6040_REG_HFRGAIN, 0x1d); + twl6040_write_reg_cache(codec, TWL6040_REG_LINEGAIN, 0); } static void twl6040_restore_regs(struct snd_soc_codec *codec) -- 2.20.1