• Hans de Goede's avatar
    ASoC: rt5640: Fix dac- and adc- vol-tlv values being off by a factor of 10 · cfa26ed1
    Hans de Goede authored
    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 3f31f7d9 ("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: default avatarHans de Goede <hdegoede@redhat.com>
    Link: https://lore.kernel.org/r/20210226143817.84287-2-hdegoede@redhat.comSigned-off-by: default avatarMark Brown <broonie@kernel.org>
    cfa26ed1
rt5640.c 87.8 KB