[PATCH 4.4 032/118] iio: ad799x: Fix buffered capture for ad7991/ad7995/ad7999

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Lars-Peter Clausen <lars@xxxxxxxxxx>

commit 7d3cc21dab5313a02f2f3ca8164529b828a030d1 upstream.

The data buffer for captured mode for the ad799x driver is allocated in the
update_scan_mode() callback. This callback is not set in the iio_info
struct for the ad7791/ad7995/ad7999, which means that the data buffer is
not allocated when a captured transfer is started. As a result the driver
crashes when the first sample is received. To fix this properly set the
update_scan_mode() callback.

Fixes: d8dca33027c1 ("staging:iio:ad799x: Preallocate sample buffer")
Signed-off-by: Lars-Peter Clausen <lars@xxxxxxxxxx>
Signed-off-by: Jonathan Cameron <jic23@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/iio/adc/ad799x.c |    1 +
 1 file changed, 1 insertion(+)

--- a/drivers/iio/adc/ad799x.c
+++ b/drivers/iio/adc/ad799x.c
@@ -533,6 +533,7 @@ static struct attribute_group ad799x_eve
 static const struct iio_info ad7991_info = {
 	.read_raw = &ad799x_read_raw,
 	.driver_module = THIS_MODULE,
+	.update_scan_mode = ad799x_update_scan_mode,
 };
 
 static const struct iio_info ad7993_4_7_8_noirq_info = {