diff options
| author | Alexander Stein <alexander.stein@systec-electronic.com> | 2015-04-16 14:51:57 +0200 |
|---|---|---|
| committer | Stefan Agner <stefan.agner@toradex.com> | 2017-05-30 13:49:04 -0700 |
| commit | ae56e9df89155df49346526e7000004dec84ebef (patch) | |
| tree | c18781b2b1c9c1deba2a9e33991360a079f71a77 /sound | |
| parent | 3db63e28b0eb01d0801a9ee6ba3ae7bfa4a1bfd8 (diff) | |
ASoC: sgtl5000: Calculate Lineout Channel Output Level
Currently LO_VOL_* stays at it's default (0x4 each) but this should be
calculated after setting VAG_VAL and LO_VAGCNTRL.
LO_VOL_* = 40 * log10(VAG_VAL / LO_VAGCNTRL) + 15
To avoid the log10 operation a table for all valid register values is
precalculated which contains the corresponding value
(VAG_VAL * 100 / LO_VAGCNTRL).
Signed-off-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
(cherry picked from commit 1f39d9397f8a27becd2b72009865610a71c64b0f)
Diffstat (limited to 'sound')
| -rw-r--r-- | sound/soc/codecs/sgtl5000.c | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/sound/soc/codecs/sgtl5000.c b/sound/soc/codecs/sgtl5000.c index bf239c883ae7..fa307fe4e15e 100644 --- a/sound/soc/codecs/sgtl5000.c +++ b/sound/soc/codecs/sgtl5000.c @@ -1100,6 +1100,19 @@ static bool sgtl5000_readable(struct device *dev, unsigned int reg) } /* + * This precalculated table contains all (vag_val * 100 / lo_calcntrl) results + * to select an appropriate lo_vol_* in SGTL5000_CHIP_LINE_OUT_VOL + * The calculatation was done for all possible register values which + * is the array index and the following formula: 10^((idx−15)/40) * 100 + */ +static const u8 vol_quot_table[] = { + 42, 45, 47, 50, 53, 56, 60, 63, + 67, 71, 75, 79, 84, 89, 94, 100, + 106, 112, 119, 126, 133, 141, 150, 158, + 168, 178, 188, 200, 211, 224, 237, 251 +}; + +/* * sgtl5000 has 3 internal power supplies: * 1. VAG, normally set to vdda/2 * 2. charge pump, set to different value @@ -1120,6 +1133,9 @@ static int sgtl5000_set_power_regs(struct snd_soc_codec *codec) u16 lreg_ctrl; int vag; int lo_vag; + int vol_quot; + int lo_vol; + size_t i; struct sgtl5000_priv *sgtl5000 = snd_soc_codec_get_drvdata(codec); vdda = regulator_get_voltage(sgtl5000->supplies[VDDA].consumer); @@ -1224,6 +1240,28 @@ static int sgtl5000_set_power_regs(struct snd_soc_codec *codec) SGTL5000_LINE_OUT_CURRENT_360u << SGTL5000_LINE_OUT_CURRENT_SHIFT); + /* + * Set lineout output level in range (0..31) + * the same value is used for right and left channel + * + * Searching for a suitable index solving this formula: + * idx = 40 * log10(vag_val / lo_cagcntrl) + 15 + */ + vol_quot = (vag * 100) / lo_vag; + lo_vol = 0; + for (i = 0; i < ARRAY_SIZE(vol_quot_table); i++) { + if (vol_quot >= vol_quot_table[i]) + lo_vol = i; + else + break; + } + + snd_soc_update_bits(codec, SGTL5000_CHIP_LINE_OUT_VOL, + SGTL5000_LINE_OUT_VOL_RIGHT_MASK | + SGTL5000_LINE_OUT_VOL_LEFT_MASK, + lo_vol << SGTL5000_LINE_OUT_VOL_RIGHT_SHIFT | + lo_vol << SGTL5000_LINE_OUT_VOL_LEFT_SHIFT); + return 0; } |