[alsa-devel] [PATCH] ASoC: rt5677: make volume TLV closer to reality

[Dylan Reid]

The volume blocks have an step of 0.375dB, but TLV uses 0.01dB for
units.  Approximate 0.375 as 0.37.  It leaves the minimum value off by
1.15dB, but that is better than being off by ~500 as it was with 37.5
as the step.

Signed-off-by: Dylan Reid <dgreid at chromium.org>
---
Just a suggestion.  It seems to me to be the lesser of two evils.
This probably won't be the last codec that has a higher resolution
than 0.01dB, should we come up with a way to express that?
---
 sound/soc/codecs/rt5677.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/sound/soc/codecs/rt5677.c b/sound/soc/codecs/rt5677.c
index 16aa4d9..f139d5a 100644
--- a/sound/soc/codecs/rt5677.c
+++ b/sound/soc/codecs/rt5677.c
@@ -538,9 +538,11 @@ static bool rt5677_readable_register(struct device *dev, unsigned int reg)
 }
 
 static const DECLARE_TLV_DB_SCALE(out_vol_tlv, -4650, 150, 0);
-static const DECLARE_TLV_DB_SCALE(dac_vol_tlv, -65625, 375, 0);
+/* Actual min=-65.625dB and step=0.375dB but only have 0.01 resolution. */
+static const DECLARE_TLV_DB_SCALE(dac_vol_tlv, -6475, 37, 0);
 static const DECLARE_TLV_DB_SCALE(in_vol_tlv, -3450, 150, 0);
-static const DECLARE_TLV_DB_SCALE(adc_vol_tlv, -17625, 375, 0);
+/* Actual min=-17.625dB and step=0.375dB but only have 0.01 resolution. */
+static const DECLARE_TLV_DB_SCALE(adc_vol_tlv, -1739, 37, 0);
 static const DECLARE_TLV_DB_SCALE(adc_bst_tlv, 0, 1200, 0);
 static const DECLARE_TLV_DB_SCALE(st_vol_tlv, -4650, 150, 0);
 
-- 
2.1.2.330.g565301e