iio: proximity: sx9500: claim direct mode during raw proximity reads

Driver was checking for direct mode but not locking it.  Use the
claim/release helper functions to guarantee the device stays in
direct mode during raw reads of proximity data.
Signed-off-by: NAlison Schofield <amsfield22@gmail.com>
Reviewed-by: NVlad Dogaru <ddvlad@gmail.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

drivers/iio/proximity/sx9500.c

@@ -387,14 +387,18 @@ static int sx9500_read_raw(struct iio_dev *indio_dev,
 			   int *val, int *val2, long mask)
 {
 	struct sx9500_data *data = iio_priv(indio_dev);
+	int ret;
 
 	switch (chan->type) {
 	case IIO_PROXIMITY:
 		switch (mask) {
 		case IIO_CHAN_INFO_RAW:
-			if (iio_buffer_enabled(indio_dev))
-				return -EBUSY;
-			return sx9500_read_proximity(data, chan, val);
+			ret = iio_device_claim_direct_mode(indio_dev);
+			if (ret)
+				return ret;
+			ret = sx9500_read_proximity(data, chan, val);
+			iio_device_release_direct_mode(indio_dev);
+			return ret;
 		case IIO_CHAN_INFO_SAMP_FREQ:
 			return sx9500_read_samp_freq(data, val, val2);
 		default: