[PATCH] iio: chemical: scd30: Replace manual locking with RAII locking

[Maxwell Doose <m32285159@gmail.com>]

scd30_core.c currently uses manual mutex_lock() and mutex_unlock()
calls. Replace them with the newer guard(mutex)() for cleaner RAII
patterns and to improve maintainability.

In addition, minor refactors in control logic to remove gotos where the
guard(mutex)() calls would be used, and replace the "?:" operator with
regular if/else returns.

Signed-off-by: Maxwell Doose <m32285159@gmail.com>
---
 drivers/iio/chemical/scd30_core.c | 53 +++++++++++++++++--------------
 1 file changed, 29 insertions(+), 24 deletions(-)

diff --git a/drivers/iio/chemical/scd30_core.c b/drivers/iio/chemical/scd30_core.c
index a665fcb78806..a24c95874fd3 100644
--- a/drivers/iio/chemical/scd30_core.c
+++ b/drivers/iio/chemical/scd30_core.c
@@ -368,11 +368,13 @@ static ssize_t calibration_auto_enable_show(struct device *dev, struct device_at
 	int ret;
 	u16 val;
 
-	mutex_lock(&state->lock);
-	ret = scd30_command_read(state, CMD_ASC, &val);
-	mutex_unlock(&state->lock);
+	guard(mutex)(&state->lock);
 
-	return ret ?: sysfs_emit(buf, "%d\n", val);
+	ret = scd30_command_read(state, CMD_ASC, &val);
+	if (ret)
+		return ret;
+
+	return sysfs_emit(buf, "%d\n", val);
 }
 
 static ssize_t calibration_auto_enable_store(struct device *dev, struct device_attribute *attr,
@@ -387,11 +389,13 @@ static ssize_t calibration_auto_enable_store(struct device *dev, struct device_a
 	if (ret)
 		return ret;
 
-	mutex_lock(&state->lock);
-	ret = scd30_command_write(state, CMD_ASC, val);
-	mutex_unlock(&state->lock);
+	guard(mutex)(&state->lock);
 
-	return ret ?: len;
+	ret = scd30_command_write(state, CMD_ASC, val);
+	if (ret)
+		return ret;
+
+	return len;
 }
 
 static ssize_t calibration_forced_value_show(struct device *dev, struct device_attribute *attr,
@@ -402,11 +406,13 @@ static ssize_t calibration_forced_value_show(struct device *dev, struct device_a
 	int ret;
 	u16 val;
 
-	mutex_lock(&state->lock);
-	ret = scd30_command_read(state, CMD_FRC, &val);
-	mutex_unlock(&state->lock);
+	guard(mutex)(&state->lock);
 
-	return ret ?: sysfs_emit(buf, "%d\n", val);
+	ret = scd30_command_read(state, CMD_FRC, &val);
+	if (ret)
+		return ret;
+
+	return sysfs_emit(buf, "%d\n", val);
 }
 
 static ssize_t calibration_forced_value_store(struct device *dev, struct device_attribute *attr,
@@ -424,11 +430,13 @@ static ssize_t calibration_forced_value_store(struct device *dev, struct device_
 	if (val < SCD30_FRC_MIN_PPM || val > SCD30_FRC_MAX_PPM)
 		return -EINVAL;
 
-	mutex_lock(&state->lock);
-	ret = scd30_command_write(state, CMD_FRC, val);
-	mutex_unlock(&state->lock);
+	guard(mutex)(&state->lock);
 
-	return ret ?: len;
+	ret = scd30_command_write(state, CMD_FRC, val);
+	if (ret)
+		return ret;
+
+	return len;
 }
 
 static IIO_DEVICE_ATTR_RO(sampling_frequency_available, 0);
@@ -590,19 +598,16 @@ static irqreturn_t scd30_trigger_handler(int irq, void *p)
 	} scan = { };
 	int ret;
 
-	mutex_lock(&state->lock);
+	guard(mutex)(&state->lock);
+
 	if (!iio_trigger_using_own(indio_dev))
 		ret = scd30_read_poll(state);
 	else
 		ret = scd30_read_meas(state);
 	memcpy(scan.data, state->meas, sizeof(state->meas));
-	mutex_unlock(&state->lock);
-	if (ret)
-		goto out;
-
-	iio_push_to_buffers_with_ts(indio_dev, &scan, sizeof(scan),
-				    iio_get_time_ns(indio_dev));
-out:
+	if (!ret)
+		iio_push_to_buffers_with_ts(indio_dev, &scan, sizeof(scan),
+					    iio_get_time_ns(indio_dev));
 	iio_trigger_notify_done(indio_dev->trig);
 	return IRQ_HANDLED;
 }
-- 
2.54.0