ASoC: apple: mca: Fix SERDES reset sequence

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[ Upstream commit d8b3e396088d787771f19fd3b7949e080dc31d6f ]

Fix the reset sequence of reads and writes that we invoke from within
the early trigger. It looks like there never was a SERDES_CONF_SOME_RST
bit that should be involved in the reset sequence, and its presence in
the driver code is a mistake from earlier.

Instead, the reset sequence should go as follows: We should switch the
the SERDES unit's SYNC_SEL mux to the value of 7 (so outside the range
of 1...6 representing cluster's SYNCGEN units), then raise the RST bit
in SERDES_STATUS and wait for it to clear.

Properly resetting the SERDES unit fixes frame desynchronization hazard
in case of long frames (longer than 4 used slots). The desynchronization
manifests itself by rotating the PCM channels.

Fixes: 3df5d0d97289 ("ASoC: apple: mca: Start new platform driver")
Signed-off-by: Martin Povišer <povik+lin@cutebit.org>
Link: https://lore.kernel.org/r/20230224153302.45365-2-povik+lin@cutebit.org
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

...

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Martin Povišer 2023-02-24 16:33:01 +01:00 • committed by Greg Kroah-Hartman

parent c664c38355

commit 0c398c1c19

1 changed files with 13 additions and 5 deletions

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sound/soc/apple/mca.c

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