• Ricard Wanderlof's avatar
    ASoC: adau17x1: Workaround for noise bug in ADC · 1e6f4fc0
    Ricard Wanderlof authored
    The ADC in the ADAU1361 (and possibly other Analog Devices codecs)
    exhibits a cyclic variation in the noise floor (in our test setup between
    -87 and -93 dB), a new value being attained within this range whenever a
    new capture stream is started. The cycle repeats after about 10 or 11
    restarts.
    
    The workaround recommended by the manufacturer is to toggle the ADOSR bit
    in the Converter Control 0 register each time a new capture stream is
    started.
    
    I have verified that the patch fixes this problem on the ADAU1361, and
    according to the manufacturer toggling the bit in question in this manner
    will at least have no detrimental effect on other chips served by this
    driver.
    Signed-off-by: default avatarRicard Wanderlof <ricardw@axis.com>
    Signed-off-by: default avatarMark Brown <broonie@kernel.org>
    Cc: stable@vger.kernel.org
    1e6f4fc0
adau17x1.h 3.9 KB