[PATCH 5.19 0679/1157] iio: dac: ad5755: Fix alignment for DMA safety

[Greg Kroah-Hartman]

From: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>

[ Upstream commit d0c167ceff2d833ee493dd58164dc87bd36e48aa ]

____cacheline_aligned is an insufficient guarantee for non-coherent DMA
on platforms with 128 byte cachelines above L1.  Switch to the updated
IIO_DMA_MINALIGN definition.

Update the comment to include 'may'.

Fixes: c499d029d805 ("iio:dac: Add ad5755 driver")
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
Acked-by: Nuno Sá <nuno.sa@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20220508175712.647246-51-jic23@xxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/iio/dac/ad5755.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/dac/ad5755.c b/drivers/iio/dac/ad5755.c
index 1a63b8456725..beadfa938d2d 100644
--- a/drivers/iio/dac/ad5755.c
+++ b/drivers/iio/dac/ad5755.c
@@ -189,14 +189,14 @@ struct ad5755_state {
 	struct mutex			lock;
 
 	/*
-	 * DMA (thus cache coherency maintenance) requires the
+	 * DMA (thus cache coherency maintenance) may require the
 	 * transfer buffers to live in their own cache lines.
 	 */
 
 	union {
 		__be32 d32;
 		u8 d8[4];
-	} data[2] ____cacheline_aligned;
+	} data[2] __aligned(IIO_DMA_MINALIGN);
 };
 
 enum ad5755_type {
-- 
2.35.1