iio: amplifiers: ad8366: Fix alignment for DMA safety

____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: e71d42e03c60 ("iio: amplifiers: New driver for AD8366 Dual-Digital Variable Gain Amplifier")
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Nuno Sá <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20220508175712.647246-42-jic23@kernel.org

diff --git a/drivers/iio/amplifiers/ad8366.c b/drivers/iio/amplifiers/ad8366.c
index 1134ae12e5319a9465453fd87bd782cd0b28e81c..f2c2ea79a07f3defd1e0b607631e06d4531d6207 100644 (file)
--- a/drivers/iio/amplifiers/ad8366.c
+++ b/drivers/iio/amplifiers/ad8366.c
@@ -45,10 +45,10 @@ struct ad8366_state {
        enum ad8366_type        type;
        struct ad8366_info      *info;
        /*
-        * DMA (thus cache coherency maintenance) requires the
+        * DMA (thus cache coherency maintenance) may require the
         * transfer buffers to live in their own cache lines.
         */
-       unsigned char           data[2] ____cacheline_aligned;
+       unsigned char           data[2] __aligned(IIO_DMA_MINALIGN);
 };
 
 static struct ad8366_info ad8366_infos[] = {