iio: adc: ad7768-1: 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 reflect that separate cachelines 'may' be
required.

Fixes: a5f8c7da3d ("iio: adc: Add AD7768-1 ADC basic support")
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Nuno Sá <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20220508175712.647246-17-jic23@kernel.org
This commit is contained in:
Jonathan Cameron 2022-05-08 18:55:56 +01:00
parent 009ae227a1
commit 211f810f8f

View File

@ -163,7 +163,7 @@ struct ad7768_state {
struct gpio_desc *gpio_sync_in;
const char *labels[ARRAY_SIZE(ad7768_channels)];
/*
* 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 {
@ -173,7 +173,7 @@ struct ad7768_state {
} scan;
__be32 d32;
u8 d8[2];
} data ____cacheline_aligned;
} data __aligned(IIO_DMA_MINALIGN);
};
static int ad7768_spi_reg_read(struct ad7768_state *st, unsigned int addr,