[PATCH 5.19 0668/1157] iio: adc: ti-tlc4541: Fix alignment for DMA safety

Greg Kroah-Hartman
2022-08-16T00:14:19Z

From: Jonathan Cameron <Jonathan.Cameron@huawei.com>

[ Upstream commit 62fa19bf484bfeb52c56b7c6d6a6b1222c597f9c ]

____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: ac2bec9d587c ("iio: adc: tlc4541: add support for TI tlc4541 adc")
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Nuno Sá <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20220508175712.647246-40-jic23@kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/iio/adc/ti-tlc4541.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/adc/ti-tlc4541.c b/drivers/iio/adc/ti-tlc4541.c
index 2406eda9dfc6..30f629a553a1 100644
--- a/drivers/iio/adc/ti-tlc4541.c
+++ b/drivers/iio/adc/ti-tlc4541.c
@@ -37,12 +37,12 @@ struct tlc4541_state {
struct spi_message scan_single_msg;

/*
- * DMA (thus cache coherency maintenance) requires the
+ * DMA (thus cache coherency maintenance) may require the
* transfer buffers to live in their own cache lines.
* 2 bytes data + 6 bytes padding + 8 bytes timestamp when
* call iio_push_to_buffers_with_timestamp.
*/
- __be16 rx_buf[8] ____cacheline_aligned;
+ __be16 rx_buf[8] __aligned(IIO_DMA_MINALIGN);
};

struct tlc4541_chip_info {
--
2.35.1