[PATCH 7/9] iio: adc: ad7606: switch mutexes to scoped_guard

[Guillaume Stols <gstols@xxxxxxxxxxxx>]

Switching to scoped_guard simplifies the code and avoids to take care to
unlock the mutex in case of premature return.

Signed-off-by: Guillaume Stols <gstols@xxxxxxxxxxxx>
---
 drivers/iio/adc/ad7606.c | 71 ++++++++++++++++++++++--------------------------
 1 file changed, 33 insertions(+), 38 deletions(-)

diff --git a/drivers/iio/adc/ad7606.c b/drivers/iio/adc/ad7606.c
index 3a417595294f..e3426287edf6 100644
--- a/drivers/iio/adc/ad7606.c
+++ b/drivers/iio/adc/ad7606.c
@@ -69,19 +69,18 @@ static int ad7606_reg_access(struct iio_dev *indio_dev,
 	struct ad7606_state *st = iio_priv(indio_dev);
 	int ret;
 
-	mutex_lock(&st->lock);
-	if (readval) {
-		ret = st->bops->reg_read(st, reg);
-		if (ret < 0)
-			goto err_unlock;
-		*readval = ret;
-		ret = 0;
-	} else {
-		ret = st->bops->reg_write(st, reg, writeval);
+	scoped_guard(mutex, &st->lock) {
+		if (readval) {
+			ret = st->bops->reg_read(st, reg);
+			if (ret < 0)
+				return ret;
+			*readval = ret;
+			return 0;
+		} else {
+			return st->bops->reg_write(st, reg, writeval);
+		}
 	}
-err_unlock:
-	mutex_unlock(&st->lock);
-	return ret;
+	unreachable();
 }
 
 static int ad7606_read_samples(struct ad7606_state *st)
@@ -124,18 +123,18 @@ static irqreturn_t ad7606_trigger_handler(int irq, void *p)
 	struct ad7606_state *st = iio_priv(indio_dev);
 	int ret;
 
-	mutex_lock(&st->lock);
+	scoped_guard(mutex, &st->lock) {
+		ret = ad7606_read_samples(st);
+		if (ret)
+			goto error_ret;
 
-	ret = ad7606_read_samples(st);
-	if (ret == 0)
 		iio_push_to_buffers_with_timestamp(indio_dev, st->data,
 						   iio_get_time_ns(indio_dev));
-
-	iio_trigger_notify_done(indio_dev->trig);
-	/* The rising edge of the CONVST signal starts a new conversion. */
-	gpiod_set_value(st->gpio_convst, 1);
-
-	mutex_unlock(&st->lock);
+error_ret:
+		iio_trigger_notify_done(indio_dev->trig);
+		/* The rising edge of the CONVST signal starts a new conversion. */
+		gpiod_set_value(st->gpio_convst, 1);
+	}
 
 	return IRQ_HANDLED;
 }
@@ -259,17 +258,15 @@ static int ad7606_write_raw(struct iio_dev *indio_dev,
 
 	switch (mask) {
 	case IIO_CHAN_INFO_SCALE:
-		mutex_lock(&st->lock);
-		i = find_closest(val2, st->scale_avail, st->num_scales);
-		if (st->sw_mode_en)
-			ch = chan->address;
-		ret = st->write_scale(indio_dev, ch, i);
-		if (ret < 0) {
-			mutex_unlock(&st->lock);
-			return ret;
+		scoped_guard(mutex, &st->lock) {
+			i = find_closest(val2, st->scale_avail, st->num_scales);
+			if (st->sw_mode_en)
+				ch = chan->address;
+			ret = st->write_scale(indio_dev, ch, i);
+			if (ret < 0)
+				return ret;
+			st->range[ch] = i;
 		}
-		st->range[ch] = i;
-		mutex_unlock(&st->lock);
 
 		return 0;
 	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
@@ -277,14 +274,12 @@ static int ad7606_write_raw(struct iio_dev *indio_dev,
 			return -EINVAL;
 		i = find_closest(val, st->oversampling_avail,
 				 st->num_os_ratios);
-		mutex_lock(&st->lock);
-		ret = st->write_os(indio_dev, i);
-		if (ret < 0) {
-			mutex_unlock(&st->lock);
-			return ret;
+		scoped_guard(mutex, &st->lock) {
+			ret = st->write_os(indio_dev, i);
+			if (ret < 0)
+				return ret;
+			st->oversampling = st->oversampling_avail[i];
 		}
-		st->oversampling = st->oversampling_avail[i];
-		mutex_unlock(&st->lock);
 
 		return 0;
 	default:

-- 
2.34.1