When changing the sample rate, the CMI8788's master clock output becomes
unstable for a short time. The AK4396 needs the master clock to do SPI
writes, so writing to an AK4396 control register directly after a sample
rate change will garble the value. In our case, this leads to the DACs
being misconfigured to I2S sample format, which results in a wrong
output level and horrible distortions on samples louder than -6 dB.
To fix this, we need to wait until the new master clock signal has
become stable before doing SPI writes.
Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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