[PATCH] iio: imu: st_lsm6dsx: do not use a fixed read len in read_oneshot

[Lorenzo Bianconi <lorenzo.bianconi@xxxxxxxxxx>]

Generalize st_lsm6dsx_shub_read_oneshot in order to not use a fixed
read length and take into account iio channel realbits for single
read operations

Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@xxxxxxxxxx>
---
 drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_shub.c | 31 +++++++++++++-------
 1 file changed, 20 insertions(+), 11 deletions(-)

diff --git a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_shub.c b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_shub.c
index ee59b0cac84f..b908df0380b3 100644
--- a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_shub.c
+++ b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_shub.c
@@ -27,6 +27,7 @@
 #include <linux/iio/iio.h>
 #include <linux/iio/sysfs.h>
 #include <linux/bitfield.h>
+#include <linux/slab.h>
 
 #include "st_lsm6dsx.h"
 
@@ -432,31 +433,39 @@ st_lsm6dsx_shub_read_oneshot(struct st_lsm6dsx_sensor *sensor,
 			     struct iio_chan_spec const *ch,
 			     int *val)
 {
-	int err, delay, len = ch->scan_type.realbits >> 3;
-	__le16 data;
+	int ret, delay, len = ch->scan_type.realbits >> 3;
+	u8 *data;
 
-	err = st_lsm6dsx_shub_set_enable(sensor, true);
-	if (err < 0)
-		return err;
+	ret = st_lsm6dsx_shub_set_enable(sensor, true);
+	if (ret < 0)
+		return ret;
+
+	data = kmalloc(len, GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
 
 	delay = 1000000 / sensor->odr;
 	usleep_range(delay, 2 * delay);
 
-	err = st_lsm6dsx_shub_read(sensor, ch->address, (u8 *)&data, len);
-	if (err < 0)
-		return err;
+	ret = st_lsm6dsx_shub_read(sensor, ch->address, data, len);
+	if (ret < 0)
+		goto out;
 
 	st_lsm6dsx_shub_set_enable(sensor, false);
 
 	switch (len) {
 	case 2:
-		*val = (s16)le16_to_cpu(data);
+		*val = (s16)le16_to_cpu(*((__le16 *)data));
+		ret = IIO_VAL_INT;
 		break;
 	default:
-		return -EINVAL;
+		ret = -EINVAL;
+		break;
 	}
 
-	return IIO_VAL_INT;
+out:
+	kfree(data);
+	return ret;
 }
 
 static int
-- 
2.19.1