iio: gyro: fxas210002c: Fix alignment for DMA safety

[ Upstream commit 3aafe923987cb4a15e16f03c6185ed4b6a78ca00 ]

____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.

Updated the comment to 'may' require.

Fixes: a0701b6263ae ("iio: gyro: add core driver for fxas21002c")
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Rui Miguel Silva <rui.silva@linaro.org>
Acked-by: Nuno Sá <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20220508175712.647246-76-jic23@kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/iio/gyro/fxas21002c_core.c b/drivers/iio/gyro/fxas21002c_core.c
index 410e5e9f2672e19584ab8a181a63f27d977ec05f..7a459a823f6e18fdfd39e4e7fd7777b3b0f24361 100644 (file)
--- a/drivers/iio/gyro/fxas21002c_core.c
+++ b/drivers/iio/gyro/fxas21002c_core.c
@@ -150,10 +150,10 @@ struct fxas21002c_data {
        struct regulator *vddio;
 
        /*
-        * DMA (thus cache coherency maintenance) requires the
-        * transfer buffers to live in their own cache lines.
+        * DMA (thus cache coherency maintenance) may require the
+        * transfer buffers live in their own cache lines.
         */
-       s16 buffer[8] ____cacheline_aligned;
+       s16 buffer[8] __aligned(IIO_DMA_MINALIGN);
 };
 
 enum fxas21002c_channel_index {