The BU27034 uses mutex for protecting the gain / time / scale changes.
The clean-up for a few of the functions can be slightly simplified by
removing the goto-based error handling/unlocking and by utilizing the
guard(mutex) scoped mutex handling instead.

Simplify driver by using the scoped mutexes.

Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
---
 drivers/iio/light/rohm-bu27034.c | 73 +++++++++++---------------------
 1 file changed, 25 insertions(+), 48 deletions(-)

diff --git a/drivers/iio/light/rohm-bu27034.c b/drivers/iio/light/rohm-bu27034.c
index 76711c3cdf7c..d2ed92d5ec92 100644
--- a/drivers/iio/light/rohm-bu27034.c
+++ b/drivers/iio/light/rohm-bu27034.c
@@ -7,6 +7,7 @@
 
 #include <linux/bitfield.h>
 #include <linux/bits.h>
+#include <linux/cleanup.h>
 #include <linux/device.h>
 #include <linux/i2c.h>
 #include <linux/module.h>
@@ -395,30 +396,26 @@ static int bu27034_try_set_int_time(struct bu27034_data *data, int time_us)
 	int numg = ARRAY_SIZE(gains);
 	int ret, int_time_old, i;
 
-	mutex_lock(&data->mutex);
+	guard(mutex)(&data->mutex);
 	ret = bu27034_get_int_time(data);
 	if (ret < 0)
-		goto unlock_out;
+		return ret;
 
 	int_time_old = ret;
 
 	if (!iio_gts_valid_time(&data->gts, time_us)) {
 		dev_err(data->dev, "Unsupported integration time %u\n",
 			time_us);
-		ret = -EINVAL;
-
-		goto unlock_out;
+		return -EINVAL;
 	}
 
-	if (time_us == int_time_old) {
-		ret = 0;
-		goto unlock_out;
-	}
+	if (time_us == int_time_old)
+		return 0;
 
 	for (i = 0; i < numg; i++) {
 		ret = bu27034_get_gain(data, gains[i].chan, &gains[i].old_gain);
 		if (ret)
-			goto unlock_out;
+			return 0;
 
 		ret = iio_gts_find_new_gain_by_old_gain_time(&data->gts,
 							     gains[i].old_gain,
@@ -434,7 +431,7 @@ static int bu27034_try_set_int_time(struct bu27034_data *data, int time_us)
 				gains[i].chan, time_us, scale1, scale2);
 
 			if (gains[i].new_gain < 0)
-				goto unlock_out;
+				return ret;
 
 			/*
 			 * If caller requests for integration time change and we
@@ -455,7 +452,7 @@ static int bu27034_try_set_int_time(struct bu27034_data *data, int time_us)
 					 "Total gain increase. Risk of saturation");
 				ret = iio_gts_get_min_gain(&data->gts);
 				if (ret < 0)
-					goto unlock_out;
+					return ret;
 			}
 			dev_dbg(data->dev, "chan %u scale changed\n",
 				 gains[i].chan);
@@ -468,15 +465,10 @@ static int bu27034_try_set_int_time(struct bu27034_data *data, int time_us)
 	for (i = 0; i < numg; i++) {
 		ret = bu27034_set_gain(data, gains[i].chan, gains[i].new_gain);
 		if (ret)
-			goto unlock_out;
+			return ret;
 	}
 
-	ret = bu27034_set_int_time(data, time_us);
-
-unlock_out:
-	mutex_unlock(&data->mutex);
-
-	return ret;
+	return bu27034_set_int_time(data, time_us);
 }
 
 static int bu27034_set_scale(struct bu27034_data *data, int chan,
@@ -492,10 +484,10 @@ static int bu27034_set_scale(struct bu27034_data *data, int chan,
 		return -EINVAL;
 	}
 
-	mutex_lock(&data->mutex);
+	guard(mutex)(&data->mutex);
 	ret = regmap_read(data->regmap, BU27034_REG_MODE_CONTROL1, &time_sel);
 	if (ret)
-		goto unlock_out;
+		return ret;
 
 	ret = iio_gts_find_gain_sel_for_scale_using_time(&data->gts, time_sel,
 						val, val2, &gain_sel);
@@ -518,7 +510,7 @@ static int bu27034_set_scale(struct bu27034_data *data, int chan,
 
 		ret = bu27034_get_gain(data, gain.chan, &gain.old_gain);
 		if (ret)
-			goto unlock_out;
+			return ret;
 
 		/*
 		 * Iterate through all the times to see if we find one which
@@ -551,26 +543,20 @@ static int bu27034_set_scale(struct bu27034_data *data, int chan,
 		if (!found) {
 			dev_dbg(data->dev,
 				"Can't set scale maintaining other channel\n");
-			ret = -EINVAL;
-
-			goto unlock_out;
+			return -EINVAL;
 		}
 
 		ret = bu27034_set_gain(data, gain.chan, gain.new_gain);
 		if (ret)
-			goto unlock_out;
+			return ret;
 
 		ret = regmap_update_bits(data->regmap, BU27034_REG_MODE_CONTROL1,
 				  BU27034_MASK_MEAS_MODE, new_time_sel);
 		if (ret)
-			goto unlock_out;
+			return ret;
 	}
 
-	ret = bu27034_write_gain_sel(data, chan, gain_sel);
-unlock_out:
-	mutex_unlock(&data->mutex);
-
-	return ret;
+	return bu27034_write_gain_sel(data, chan, gain_sel);
 }
 
 /*
@@ -1221,42 +1207,33 @@ static int bu27034_buffer_enable(struct iio_dev *idev)
 	struct task_struct *task;
 	int ret;
 
-	mutex_lock(&data->mutex);
+	guard(mutex)(&data->mutex);
 	ret = bu27034_meas_set(data, true);
 	if (ret)
-		goto unlock_out;
+		return ret;
 
 	task = kthread_run(bu27034_buffer_thread, idev,
 				 "bu27034-buffering-%u",
 				 iio_device_id(idev));
-	if (IS_ERR(task)) {
-		ret = PTR_ERR(task);
-		goto unlock_out;
-	}
+	if (IS_ERR(task))
+		return PTR_ERR(task);
 
 	data->task = task;
 
-unlock_out:
-	mutex_unlock(&data->mutex);
-
-	return ret;
+	return 0;
 }
 
 static int bu27034_buffer_disable(struct iio_dev *idev)
 {
 	struct bu27034_data *data = iio_priv(idev);
-	int ret;
 
-	mutex_lock(&data->mutex);
+	guard(mutex)(&data->mutex);
 	if (data->task) {
 		kthread_stop(data->task);
 		data->task = NULL;
 	}
 
-	ret = bu27034_meas_set(data, false);
-	mutex_unlock(&data->mutex);
-
-	return ret;
+	return bu27034_meas_set(data, false);
 }
 
 static const struct iio_buffer_setup_ops bu27034_buffer_ops = {
-- 
2.47.0

On 21/11/2024 14:05, Matti Vaittinen wrote:
> The BU27034 uses mutex for protecting the gain / time / scale changes.
> The clean-up for a few of the functions can be slightly simplified by
> removing the goto-based error handling/unlocking and by utilizing the
> guard(mutex) scoped mutex handling instead.
> 
> Simplify driver by using the scoped mutexes.
> 
> Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
> ---
>  drivers/iio/light/rohm-bu27034.c | 73 +++++++++++---------------------
>  1 file changed, 25 insertions(+), 48 deletions(-)
> 

Reviewed-by: Javier Carrasco <javier.carrasco.cruz@gmail.com>