dmaengine: apple-admac: Keep upper bits of REG_BUS_WIDTH

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[ Upstream commit 306f5df81f ]

For RX channels, REG_BUS_WIDTH seems to default to a value of 0xf00, and
macOS preserves the upper bits when setting the configuration in the
lower ones. If we reset the upper bits to 0, this causes framing errors
on suspend/resume (the data stream "tears" and channels get swapped
around). Keeping the upper bits untouched, like the macOS driver does,
fixes this issue.

Signed-off-by: Hector Martin <marcan@marcan.st>
Reviewed-by: Martin Povišer <povik+lin@cutebit.org>
Signed-off-by: Martin Povišer <povik+lin@cutebit.org>
Link: https://lore.kernel.org/r/20231029170704.82238-1-povik+lin@cutebit.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

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Hector Martin 2023-10-29 18:07:04 +01:00 • committed by Greg Kroah-Hartman

parent 0d27ac1779

commit c9ae228cfd

1 changed files with 4 additions and 1 deletions

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drivers/dma/apple-admac.c

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