[PATCH 5.12 081/296] iio: adc: ad7923: Fix undersized rx buffer.

[Greg Kroah-Hartman]

From: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>

commit 01fcf129f61b26d5b3d2d8afb03e770dee271bc8 upstream.

Fixes tag is where the max channels became 8, but timestamp space was missing
before that.

Fixes: 851644a60d20 ("iio: adc: ad7923: Add support for the ad7908/ad7918/ad7928")
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
Cc: Daniel Junho <djunho@xxxxxxxxx>
Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
Link: https://lore.kernel.org/r/20210501165314.511954-3-jic23@xxxxxxxxxx
Cc: <Stable@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/iio/adc/ad7923.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/drivers/iio/adc/ad7923.c
+++ b/drivers/iio/adc/ad7923.c
@@ -59,8 +59,10 @@ struct ad7923_state {
 	/*
 	 * DMA (thus cache coherency maintenance) requires the
 	 * transfer buffers to live in their own cache lines.
+	 * Ensure rx_buf can be directly used in iio_push_to_buffers_with_timetamp
+	 * Length = 8 channels + 4 extra for 8 byte timestamp
 	 */
-	__be16				rx_buf[4] ____cacheline_aligned;
+	__be16				rx_buf[12] ____cacheline_aligned;
 	__be16				tx_buf[4];
 };