• Philipp Zabel's avatar
    ASoC: ssm2602: Fix ADC powerup sequencing · 37768e39
    Philipp Zabel authored
    According to the ssm2603 data sheet (control register sequencing), the
    digital core should be activated only after all necessary bits in the
    power register are enabled, and a delay determined by the decoupling
    capacitor on the VMID pin has passed. If the digital core is activated
    too early, or even before the ADC is powered up, audible artifacts
    appear at the beginning of the recorded signal.
    
    The digital core is also needed for playback, so when recording starts
    it may already be enabled. This means we cannot get the power sequence
    correct when we want to be able to start recording after playback.
    
    As a workaround put the MIC mute switch into the DAPM routes. This
    way we can keep the recording disabled until the MIC Bias has settled
    and thus get rid of audible artifacts.
    Signed-off-by: default avatarPhilipp Zabel <p.zabel@pengutronix.de>
    m.felsch@pengutronix.de: adapt commit message
    m.felsch@pengutronix.de: drop of configuration as mentioned by Mark:
    			 https://patchwork.kernel.org/patch/10407449/Signed-off-by: default avatarMarco Felsch <m.felsch@pengutronix.de>
    Signed-off-by: default avatarMark Brown <broonie@kernel.org>
    37768e39
ssm2602.c 18.7 KB