[PATCH v2 1/4] iio: magnetometer: rm3100: Use guard(mutex)() in rm3100_read_mag()

[Maxwell Doose]

Replace mutex_lock() and mutex_unlock() calls in rm3100_read_mag() with
the more modern guard(mutex)(). This will help modernize the driver and
bring it up-to-date with modern available macros/functions.

While at it, remove the now unnecessary "unlock_return" goto and
directly return in if statements.

Signed-off-by: Maxwell Doose <m32285159@xxxxxxxxx>
---
v2:
 - Switch out scoped_guard() for guard(mutex)() per Andy.

 drivers/iio/magnetometer/rm3100-core.c | 14 +++++---------
 1 file changed, 5 insertions(+), 9 deletions(-)

diff --git a/drivers/iio/magnetometer/rm3100-core.c b/drivers/iio/magnetometer/rm3100-core.c
index 2b2884425746..426963935d60 100644
--- a/drivers/iio/magnetometer/rm3100-core.c
+++ b/drivers/iio/magnetometer/rm3100-core.c
@@ -204,27 +204,23 @@ static int rm3100_read_mag(struct rm3100_data *data, int idx, int *val)
 	u8 buffer[3];
 	int ret;
 
-	mutex_lock(&data->lock);
+	guard(mutex)(&data->lock);
+
 	ret = regmap_write(regmap, RM3100_REG_POLL, BIT(4 + idx));
 	if (ret < 0)
-		goto unlock_return;
+		return ret;
 
 	ret = rm3100_wait_measurement(data);
 	if (ret < 0)
-		goto unlock_return;
+		return ret;
 
 	ret = regmap_bulk_read(regmap, RM3100_REG_MX2 + 3 * idx, buffer, 3);
 	if (ret < 0)
-		goto unlock_return;
-	mutex_unlock(&data->lock);
+		return ret;
 
 	*val = sign_extend32(get_unaligned_be24(&buffer[0]), 23);
 
 	return IIO_VAL_INT;
-
-unlock_return:
-	mutex_unlock(&data->lock);
-	return ret;
 }
 
 #define RM3100_CHANNEL(axis, idx)					\
-- 
2.53.0