[PATCH v2 2/2] iio: adc: ad4080: configure backend data size

[Antoniu Miclaus]

The AXI backend needs to know the ADC word width in order to pack the
sample data correctly on the bus. During channel setup, program the
backend packet format via iio_backend_data_size_set() using the channel
resolution, so the data is transferred according to the device's
realbits.

The backend packet format field defaults to 20-bit packing, so the
20-bit parts (AD4080/AD4081/AD4082, AD4880) were unaffected. The 16-bit
(AD4083/AD4084/AD4085, AD4884) and 14-bit (AD4086/AD4087/AD4088) parts,
however, were left packing data at the wrong width, producing corrupt
buffered captures.

Fixes: 6c3e7265734b ("iio: adc: ad4080: add support for AD4084")
Signed-off-by: Antoniu Miclaus <antoniu.miclaus@xxxxxxxxxx>
---
changes in v2:
 - Expand the commit message to describe which parts are affected by the
   wrong packet format.
 - Add a Fixes tag

 drivers/iio/adc/ad4080.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/iio/adc/ad4080.c b/drivers/iio/adc/ad4080.c
index 8d2953341b15..8feb0c7f7fcb 100644
--- a/drivers/iio/adc/ad4080.c
+++ b/drivers/iio/adc/ad4080.c
@@ -698,6 +698,11 @@ static int ad4080_setup_channel(struct ad4080_state *st, unsigned int ch)
 	if (ret)
 		return ret;
 
+	ret = iio_backend_data_size_set(st->back[ch],
+					st->info->channels[0].scan_type.realbits);
+	if (ret)
+		return ret;
+
 	if (!st->lvds_cnv_en)
 		return 0;
 
-- 
2.43.0