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    Subject[PATCH 5.4 12/74] ASoC: rt5651: Fix dac- and adc- vol-tlv values being off by a factor of 10
    Date
    From: Hans de Goede <hdegoede@redhat.com>

    [ Upstream commit eee51df776bd6cac10a76b2779a9fdee3f622b2b ]

    The adc_vol_tlv volume-control has a range from -17.625 dB to +30 dB,
    not -176.25 dB to + 300 dB. This wrong scale is esp. a problem in userspace
    apps which translate the dB scale to a linear scale. With the logarithmic
    dB scale being of by a factor of 10 we loose all precision in the lower
    area of the range when apps translate things to a linear scale.

    E.g. the 0 dB default, which corresponds with a value of 47 of the
    0 - 127 range for the control, would be shown as 0/100 in alsa-mixer.

    Since the centi-dB values used in the TLV struct cannot represent the
    0.375 dB step size used by these controls, change the TLV definition
    for them to specify a min and max value instead of min + stepsize.

    Note this mirrors commit 3f31f7d9b540 ("ASoC: rt5670: Fix dac- and adc-
    vol-tlv values being off by a factor of 10") which made the exact same
    change to the rt5670 codec driver.

    Signed-off-by: Hans de Goede <hdegoede@redhat.com>
    Link: https://lore.kernel.org/r/20210226143817.84287-3-hdegoede@redhat.com
    Signed-off-by: Mark Brown <broonie@kernel.org>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    sound/soc/codecs/rt5651.c | 4 ++--
    1 file changed, 2 insertions(+), 2 deletions(-)

    diff --git a/sound/soc/codecs/rt5651.c b/sound/soc/codecs/rt5651.c
    index c506c9305043..829cf552fe3e 100644
    --- a/sound/soc/codecs/rt5651.c
    +++ b/sound/soc/codecs/rt5651.c
    @@ -285,9 +285,9 @@ static bool rt5651_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);
    +static const DECLARE_TLV_DB_MINMAX(dac_vol_tlv, -6562, 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);
    +static const DECLARE_TLV_DB_MINMAX(adc_vol_tlv, -1762, 3000);
    static const DECLARE_TLV_DB_SCALE(adc_bst_tlv, 0, 1200, 0);

    /* {0, +20, +24, +30, +35, +40, +44, +50, +52} dB */
    --
    2.30.1


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