iio: adc: ad7606: switch mutexes to guard

Switching to guard simplifies the code and avoids to take care to
unlock the mutex in case of premature return.
Signed-off-by: Guillaume Stols <gstols@baylibre.com>
Reviewed-by: Nuno Sa <nuno.sa@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/ad7606.c

@@ -69,19 +69,17 @@ static int ad7606_reg_access(struct iio_dev *indio_dev,
 	struct ad7606_state *st = iio_priv(indio_dev);
 	int ret;
 
-	mutex_lock(&st->lock);
+	guard(mutex)(&st->lock);
+
 	if (readval) {
 		ret = st->bops->reg_read(st, reg);
 		if (ret < 0)
-			goto err_unlock;
+			return ret;
 		*readval = ret;
-		ret = 0;
+		return 0;
 	} else {
-		ret = st->bops->reg_write(st, reg, writeval);
+		return st->bops->reg_write(st, reg, writeval);
 	}
-err_unlock:
-	mutex_unlock(&st->lock);
-	return ret;
 }
 
 static int ad7606_read_samples(struct ad7606_state *st)
@@ -124,19 +122,19 @@ static irqreturn_t ad7606_trigger_handler(int irq, void *p)
 	struct ad7606_state *st = iio_priv(indio_dev);
 	int ret;
 
-	mutex_lock(&st->lock);
+	guard(mutex)(&st->lock);
 
 	ret = ad7606_read_samples(st);
-	if (ret == 0)
-		iio_push_to_buffers_with_timestamp(indio_dev, st->data,
-						   iio_get_time_ns(indio_dev));
+	if (ret)
+		goto error_ret;
 
+	iio_push_to_buffers_with_timestamp(indio_dev, st->data,
+					   iio_get_time_ns(indio_dev));
+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);
 
-	mutex_unlock(&st->lock);
-
 	return IRQ_HANDLED;
 }
 
@@ -257,19 +255,17 @@ static int ad7606_write_raw(struct iio_dev *indio_dev,
 	struct ad7606_state *st = iio_priv(indio_dev);
 	int i, ret, ch = 0;
 
+	guard(mutex)(&st->lock);
+
 	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);
+		if (ret < 0)
 			return ret;
-		}
 		st->range[ch] = i;
-		mutex_unlock(&st->lock);
 
 		return 0;
 	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
@@ -277,14 +273,9 @@ 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);
+		if (ret < 0)
 			return ret;
-		}
-		st->oversampling = st->oversampling_avail[i];
-		mutex_unlock(&st->lock);
 
 		return 0;
 	default: