[PATCH] iio: chemical: sps30: Replace manual locking with RAII locking

[Maxwell Doose]

Replace manual mutex_lock() and mutex_unlock() calls with the much newer
guard(mutex)() and scoped_guard() macros to enable RAII patterns,
modernize the driver, and to increase readability.

Signed-off-by: Maxwell Doose <m32285159@xxxxxxxxx>
---
 drivers/iio/chemical/sps30.c | 60 +++++++++++++++++-------------------
 1 file changed, 29 insertions(+), 31 deletions(-)

diff --git a/drivers/iio/chemical/sps30.c b/drivers/iio/chemical/sps30.c
index a934bf0298dd..186dec4cfd78 100644
--- a/drivers/iio/chemical/sps30.c
+++ b/drivers/iio/chemical/sps30.c
@@ -5,6 +5,7 @@
  * Copyright (c) Tomasz Duszynski <tduszyns@xxxxxxxxx>
  */
 
+#include <linux/cleanup.h>
 #include <linux/crc8.h>
 #include <linux/delay.h>
 #include <linux/i2c.h>
@@ -111,9 +112,9 @@ static irqreturn_t sps30_trigger_handler(int irq, void *p)
 		aligned_s64 ts;
 	} scan;
 
-	mutex_lock(&state->lock);
-	ret = sps30_do_meas(state, scan.data, ARRAY_SIZE(scan.data));
-	mutex_unlock(&state->lock);
+	scoped_guard(mutex, &state->lock)
+		ret = sps30_do_meas(state, scan.data, ARRAY_SIZE(scan.data));
+
 	if (ret)
 		goto err;
 
@@ -136,23 +137,23 @@ static int sps30_read_raw(struct iio_dev *indio_dev,
 	case IIO_CHAN_INFO_PROCESSED:
 		switch (chan->type) {
 		case IIO_MASSCONCENTRATION:
-			mutex_lock(&state->lock);
-			/* read up to the number of bytes actually needed */
-			switch (chan->channel2) {
-			case IIO_MOD_PM1:
-				ret = sps30_do_meas(state, data, 1);
-				break;
-			case IIO_MOD_PM2P5:
-				ret = sps30_do_meas(state, data, 2);
-				break;
-			case IIO_MOD_PM4:
-				ret = sps30_do_meas(state, data, 3);
-				break;
-			case IIO_MOD_PM10:
-				ret = sps30_do_meas(state, data, 4);
-				break;
+			scoped_guard(mutex, &state->lock) {
+				/* read up to the number of bytes actually needed */
+				switch (chan->channel2) {
+				case IIO_MOD_PM1:
+					ret = sps30_do_meas(state, data, 1);
+					break;
+				case IIO_MOD_PM2P5:
+					ret = sps30_do_meas(state, data, 2);
+					break;
+				case IIO_MOD_PM4:
+					ret = sps30_do_meas(state, data, 3);
+					break;
+				case IIO_MOD_PM10:
+					ret = sps30_do_meas(state, data, 4);
+					break;
+				}
 			}
-			mutex_unlock(&state->lock);
 			if (ret)
 				return ret;
 
@@ -197,9 +198,9 @@ static ssize_t start_cleaning_store(struct device *dev,
 	if (kstrtoint(buf, 0, &val) || val != 1)
 		return -EINVAL;
 
-	mutex_lock(&state->lock);
-	ret = state->ops->clean_fan(state);
-	mutex_unlock(&state->lock);
+	scoped_guard(mutex, &state->lock)
+		ret = state->ops->clean_fan(state);
+
 	if (ret)
 		return ret;
 
@@ -215,9 +216,9 @@ static ssize_t cleaning_period_show(struct device *dev,
 	__be32 val;
 	int ret;
 
-	mutex_lock(&state->lock);
-	ret = state->ops->read_cleaning_period(state, &val);
-	mutex_unlock(&state->lock);
+	scoped_guard(mutex, &state->lock)
+		ret = state->ops->read_cleaning_period(state, &val);
+
 	if (ret)
 		return ret;
 
@@ -238,12 +239,11 @@ static ssize_t cleaning_period_store(struct device *dev, struct device_attribute
 	    (val > SPS30_AUTO_CLEANING_PERIOD_MAX))
 		return -EINVAL;
 
-	mutex_lock(&state->lock);
+	guard(mutex)(&state->lock);
+
 	ret = state->ops->write_cleaning_period(state, cpu_to_be32(val));
-	if (ret) {
-		mutex_unlock(&state->lock);
+	if (ret)
 		return ret;
-	}
 
 	msleep(20);
 
@@ -256,8 +256,6 @@ static ssize_t cleaning_period_store(struct device *dev, struct device_attribute
 		dev_warn(dev,
 			 "period changed but reads will return the old value\n");
 
-	mutex_unlock(&state->lock);
-
 	return len;
 }
 
-- 
2.54.0