[PATCH] ASoC: Fix maximum value for microphone gain

[PATCH] ASoC: Fix maximum value for microphone gain

[Fabio Estevam]

From: Fabio Estevam <fabio.estevam@freescale.com>

sgtl5000 microphone gain only has 2 bits of resolution, so maximum value is 3.

>From Eric Nelson:
"We also found that for the microphones we have here (commodity PC boom mics) a 
default value of 2 for the gain gives the best results."

So change the default microphone gain as well.

Signed-off-by: Eric Nelson <eric.nelson@boundarydevices.com>
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
---
 sound/soc/codecs/sgtl5000.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/sound/soc/codecs/sgtl5000.c b/sound/soc/codecs/sgtl5000.c
index cb1675c..92bbfec 100644
--- a/sound/soc/codecs/sgtl5000.c
+++ b/sound/soc/codecs/sgtl5000.c
@@ -401,7 +401,7 @@ static const struct snd_kcontrol_new sgtl5000_snd_controls[] = {
 			5, 1, 0),
 
 	SOC_SINGLE_TLV("Mic Volume", SGTL5000_CHIP_MIC_CTRL,
-			0, 4, 0, mic_gain_tlv),
+			0, 3, 0, mic_gain_tlv),
 };
 
 /* mute the codec used by alsa core */
@@ -1344,7 +1344,7 @@ static int sgtl5000_probe(struct snd_soc_codec *codec)
 			SGTL5000_HP_ZCD_EN |
 			SGTL5000_ADC_ZCD_EN);
 
-	snd_soc_write(codec, SGTL5000_CHIP_MIC_CTRL, 0);
+	snd_soc_write(codec, SGTL5000_CHIP_MIC_CTRL, 2);
 
 	/*
 	 * disable DAP
-- 
1.7.9.5

Re: [PATCH] ASoC: Fix maximum value for microphone gain

[Mark Brown]

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On Sun, Dec 23, 2012 at 03:41:19PM -0200, Fabio Estevam wrote:
> From: Fabio Estevam <fabio.estevam@freescale.com>
> 
> sgtl5000 microphone gain only has 2 bits of resolution, so maximum value is 3.
> 
> From Eric Nelson:
> "We also found that for the microphones we have here (commodity PC boom mics) a 
> default value of 2 for the gain gives the best results."
> 
> So change the default microphone gain as well.

The first bit is fine but the default change is not generally the sort
of thing we do in ASoC - we generally go with the chip defaults, it
saves on going round in circles arguing about what the defaults should
be.  Why would other systems not want a different default?

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