[PATCH 3/3] iio: light: tcs3472: Use guard(mutex)() family over manual locking

[Aldo Conte]

Convert tcs3472_read_event_config, tcs3472_write_event_config,
tcs3472_write_event, tcs3472_powerdown and tcs3472_resume to use
automatico cleanup with guard(mutex)() instead of the old manual
locking method.

Found by code inspection.

Tested on a Raspberry Pi 3B with a TCS34725 at 0x29 address.
The following fields were read and written without any issues:
sampling_frequency, integration_time, calibscale and the
threshold event interface.
The unload of the driver works cleanly.

Signed-off-by: Aldo Conte <aldocontelk@xxxxxxxxx>
---
 drivers/iio/light/tcs3472.c | 39 ++++++++++++-------------------------
 1 file changed, 12 insertions(+), 27 deletions(-)

diff --git a/drivers/iio/light/tcs3472.c b/drivers/iio/light/tcs3472.c
index de51eb61f42a..90552f47a373 100644
--- a/drivers/iio/light/tcs3472.c
+++ b/drivers/iio/light/tcs3472.c
@@ -393,7 +393,7 @@ static int tcs3472_write_event(struct iio_dev *indio_dev,
 	int period;
 	int i;
 
-	mutex_lock(&data->lock);
+	guard(mutex)(&data->lock);
 	switch (info) {
 	case IIO_EV_INFO_VALUE:
 		switch (dir) {
@@ -404,18 +404,17 @@ static int tcs3472_write_event(struct iio_dev *indio_dev,
 			command = TCS3472_AILT;
 			break;
 		default:
-			ret = -EINVAL;
-			goto error;
+			return -EINVAL;
 		}
 		ret = i2c_smbus_write_word_data(data->client, command, val);
 		if (ret)
-			goto error;
+			return ret;
 
 		if (dir == IIO_EV_DIR_RISING)
 			data->high_thresh = val;
 		else
 			data->low_thresh = val;
-		break;
+		return 0;
 	case IIO_EV_INFO_PERIOD:
 		period = val * USEC_PER_SEC + val2;
 		for (i = 1; i < ARRAY_SIZE(tcs3472_intr_pers) - 1; i++) {
@@ -425,18 +424,13 @@ static int tcs3472_write_event(struct iio_dev *indio_dev,
 		}
 		ret = i2c_smbus_write_byte_data(data->client, TCS3472_PERS, i);
 		if (ret)
-			goto error;
+			return ret;
 
 		data->apers = i;
-		break;
+		return 0;
 	default:
-		ret = -EINVAL;
-		break;
+		return -EINVAL;
 	}
-error:
-	mutex_unlock(&data->lock);
-
-	return ret;
 }
 
 static int tcs3472_read_event_config(struct iio_dev *indio_dev,
@@ -444,13 +438,9 @@ static int tcs3472_read_event_config(struct iio_dev *indio_dev,
 	enum iio_event_direction dir)
 {
 	struct tcs3472_data *data = iio_priv(indio_dev);
-	int ret;
 
-	mutex_lock(&data->lock);
-	ret = !!(data->enable & TCS3472_ENABLE_AIEN);
-	mutex_unlock(&data->lock);
-
-	return ret;
+	guard(mutex)(&data->lock);
+	return !!(data->enable & TCS3472_ENABLE_AIEN);
 }
 
 static int tcs3472_write_event_config(struct iio_dev *indio_dev,
@@ -461,7 +451,7 @@ static int tcs3472_write_event_config(struct iio_dev *indio_dev,
 	int ret = 0;
 	u8 enable_old;
 
-	mutex_lock(&data->lock);
+	guard(mutex)(&data->lock);
 
 	enable_old = data->enable;
 
@@ -476,7 +466,6 @@ static int tcs3472_write_event_config(struct iio_dev *indio_dev,
 		if (ret)
 			data->enable = enable_old;
 	}
-	mutex_unlock(&data->lock);
 
 	return ret;
 }
@@ -580,15 +569,13 @@ static int tcs3472_powerdown(struct tcs3472_data *data)
 	u8 enable_mask = TCS3472_ENABLE_AEN | TCS3472_ENABLE_PON |
 			TCS3472_ENABLE_WEN;
 
-	mutex_lock(&data->lock);
+	guard(mutex)(&data->lock);
 
 	ret = i2c_smbus_write_byte_data(data->client, TCS3472_ENABLE,
 					data->enable & ~enable_mask);
 	if (!ret)
 		data->enable &= ~enable_mask;
 
-	mutex_unlock(&data->lock);
-
 	return ret;
 }
 
@@ -722,15 +709,13 @@ static int tcs3472_resume(struct device *dev)
 	u8 enable_mask = TCS3472_ENABLE_AEN | TCS3472_ENABLE_PON |
 			TCS3472_ENABLE_WEN;
 
-	mutex_lock(&data->lock);
+	guard(mutex)(&data->lock);
 
 	ret = i2c_smbus_write_byte_data(data->client, TCS3472_ENABLE,
 		data->enable | enable_mask);
 	if (!ret)
 		data->enable |= enable_mask;
 
-	mutex_unlock(&data->lock);
-
 	return ret;
 }
 
-- 
2.54.0