[PATCH 2/7] iio: dac: ad5592r: use lock guards

[Bartosz Golaszewski]

From: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>

Use lock guards from linux/cleanup.h to simplify the code and remove
some labels.

Note that we need to initialize some variables even though it's not
technically required as scoped_guards() are implemented as for loops.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>
---
 drivers/iio/dac/ad5592r-base.c | 119 ++++++++++++++++-------------------------
 1 file changed, 47 insertions(+), 72 deletions(-)

diff --git a/drivers/iio/dac/ad5592r-base.c b/drivers/iio/dac/ad5592r-base.c
index fe4c35689d4d..bbe3b52c6a12 100644
--- a/drivers/iio/dac/ad5592r-base.c
+++ b/drivers/iio/dac/ad5592r-base.c
@@ -7,6 +7,7 @@
  */
 
 #include <linux/bitops.h>
+#include <linux/cleanup.h>
 #include <linux/delay.h>
 #include <linux/iio/iio.h>
 #include <linux/module.h>
@@ -24,16 +25,14 @@ static int ad5592r_gpio_get(struct gpio_chip *chip, unsigned offset)
 {
 	struct ad5592r_state *st = gpiochip_get_data(chip);
 	int ret = 0;
-	u8 val;
+	u8 val = 0;
 
-	mutex_lock(&st->gpio_lock);
-
-	if (st->gpio_out & BIT(offset))
-		val = st->gpio_val;
-	else
-		ret = st->ops->gpio_read(st, &val);
-
-	mutex_unlock(&st->gpio_lock);
+	scoped_guard(mutex, &st->gpio_lock) {
+		if (st->gpio_out & BIT(offset))
+			val = st->gpio_val;
+		else
+			ret = st->ops->gpio_read(st, &val);
+	}
 
 	if (ret < 0)
 		return ret;
@@ -45,7 +44,7 @@ static void ad5592r_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
 {
 	struct ad5592r_state *st = gpiochip_get_data(chip);
 
-	mutex_lock(&st->gpio_lock);
+	guard(mutex)(&st->gpio_lock);
 
 	if (value)
 		st->gpio_val |= BIT(offset);
@@ -53,8 +52,6 @@ static void ad5592r_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
 		st->gpio_val &= ~BIT(offset);
 
 	st->ops->reg_write(st, AD5592R_REG_GPIO_SET, st->gpio_val);
-
-	mutex_unlock(&st->gpio_lock);
 }
 
 static int ad5592r_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
@@ -62,21 +59,16 @@ static int ad5592r_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
 	struct ad5592r_state *st = gpiochip_get_data(chip);
 	int ret;
 
-	mutex_lock(&st->gpio_lock);
+	guard(mutex)(&st->gpio_lock);
 
 	st->gpio_out &= ~BIT(offset);
 	st->gpio_in |= BIT(offset);
 
 	ret = st->ops->reg_write(st, AD5592R_REG_GPIO_OUT_EN, st->gpio_out);
 	if (ret < 0)
-		goto err_unlock;
+		return ret;
 
-	ret = st->ops->reg_write(st, AD5592R_REG_GPIO_IN_EN, st->gpio_in);
-
-err_unlock:
-	mutex_unlock(&st->gpio_lock);
-
-	return ret;
+	return st->ops->reg_write(st, AD5592R_REG_GPIO_IN_EN, st->gpio_in);
 }
 
 static int ad5592r_gpio_direction_output(struct gpio_chip *chip,
@@ -85,7 +77,7 @@ static int ad5592r_gpio_direction_output(struct gpio_chip *chip,
 	struct ad5592r_state *st = gpiochip_get_data(chip);
 	int ret;
 
-	mutex_lock(&st->gpio_lock);
+	guard(mutex)(&st->gpio_lock);
 
 	if (value)
 		st->gpio_val |= BIT(offset);
@@ -97,18 +89,13 @@ static int ad5592r_gpio_direction_output(struct gpio_chip *chip,
 
 	ret = st->ops->reg_write(st, AD5592R_REG_GPIO_SET, st->gpio_val);
 	if (ret < 0)
-		goto err_unlock;
+		return ret;
 
 	ret = st->ops->reg_write(st, AD5592R_REG_GPIO_OUT_EN, st->gpio_out);
 	if (ret < 0)
-		goto err_unlock;
+		return ret;
 
-	ret = st->ops->reg_write(st, AD5592R_REG_GPIO_IN_EN, st->gpio_in);
-
-err_unlock:
-	mutex_unlock(&st->gpio_lock);
-
-	return ret;
+	return st->ops->reg_write(st, AD5592R_REG_GPIO_IN_EN, st->gpio_in);
 }
 
 static int ad5592r_gpio_request(struct gpio_chip *chip, unsigned offset)
@@ -171,10 +158,9 @@ static int ad5592r_reset(struct ad5592r_state *st)
 		udelay(1);
 		gpiod_set_value(gpio, 1);
 	} else {
-		mutex_lock(&st->lock);
-		/* Writing this magic value resets the device */
-		st->ops->reg_write(st, AD5592R_REG_RESET, 0xdac);
-		mutex_unlock(&st->lock);
+		scoped_guard(mutex, &st->lock)
+			/* Writing this magic value resets the device */
+			st->ops->reg_write(st, AD5592R_REG_RESET, 0xdac);
 	}
 
 	udelay(250);
@@ -249,45 +235,43 @@ static int ad5592r_set_channel_modes(struct ad5592r_state *st)
 		}
 	}
 
-	mutex_lock(&st->lock);
+	guard(mutex)(&st->lock);
 
 	/* Pull down unused pins to GND */
 	ret = ops->reg_write(st, AD5592R_REG_PULLDOWN, pulldown);
 	if (ret)
-		goto err_unlock;
+		return ret;
 
 	ret = ops->reg_write(st, AD5592R_REG_TRISTATE, tristate);
 	if (ret)
-		goto err_unlock;
+		return ret;
 
 	/* Configure pins that we use */
 	ret = ops->reg_write(st, AD5592R_REG_DAC_EN, dac);
 	if (ret)
-		goto err_unlock;
+		return ret;
 
 	ret = ops->reg_write(st, AD5592R_REG_ADC_EN, adc);
 	if (ret)
-		goto err_unlock;
+		return ret;
 
 	ret = ops->reg_write(st, AD5592R_REG_GPIO_SET, st->gpio_val);
 	if (ret)
-		goto err_unlock;
+		return ret;
 
 	ret = ops->reg_write(st, AD5592R_REG_GPIO_OUT_EN, st->gpio_out);
 	if (ret)
-		goto err_unlock;
+		return ret;
 
 	ret = ops->reg_write(st, AD5592R_REG_GPIO_IN_EN, st->gpio_in);
 	if (ret)
-		goto err_unlock;
+		return ret;
 
 	/* Verify that we can read back at least one register */
 	ret = ops->reg_read(st, AD5592R_REG_ADC_EN, &read_back);
 	if (!ret && (read_back & 0xff) != adc)
 		ret = -EIO;
 
-err_unlock:
-	mutex_unlock(&st->lock);
 	return ret;
 }
 
@@ -316,11 +300,10 @@ static int ad5592r_write_raw(struct iio_dev *iio_dev,
 		if (!chan->output)
 			return -EINVAL;
 
-		mutex_lock(&st->lock);
+		guard(mutex)(&st->lock);
 		ret = st->ops->write_dac(st, chan->channel, val);
 		if (!ret)
 			st->cached_dac[chan->channel] = val;
-		mutex_unlock(&st->lock);
 		return ret;
 	case IIO_CHAN_INFO_SCALE:
 		if (chan->type == IIO_VOLTAGE) {
@@ -335,7 +318,7 @@ static int ad5592r_write_raw(struct iio_dev *iio_dev,
 			else
 				return -EINVAL;
 
-			mutex_lock(&st->lock);
+			guard(mutex)(&st->lock);
 
 			ret = st->ops->reg_read(st, AD5592R_REG_CTRL,
 						&st->cached_gp_ctrl);
@@ -360,11 +343,8 @@ static int ad5592r_write_raw(struct iio_dev *iio_dev,
 						~AD5592R_REG_CTRL_ADC_RANGE;
 			}
 
-			ret = st->ops->reg_write(st, AD5592R_REG_CTRL,
-						 st->cached_gp_ctrl);
-			mutex_unlock(&st->lock);
-
-			return ret;
+			return st->ops->reg_write(st, AD5592R_REG_CTRL,
+						  st->cached_gp_ctrl);
 		}
 		break;
 	default:
@@ -379,15 +359,15 @@ static int ad5592r_read_raw(struct iio_dev *iio_dev,
 			   int *val, int *val2, long m)
 {
 	struct ad5592r_state *st = iio_priv(iio_dev);
-	u16 read_val;
-	int ret, mult;
+	u16 read_val = 0;
+	int ret = 0, mult = 0;
 
 	switch (m) {
 	case IIO_CHAN_INFO_RAW:
 		if (!chan->output) {
-			mutex_lock(&st->lock);
-			ret = st->ops->read_adc(st, chan->channel, &read_val);
-			mutex_unlock(&st->lock);
+			scoped_guard(mutex, &st->lock)
+				ret = st->ops->read_adc(st, chan->channel,
+							&read_val);
 			if (ret)
 				return ret;
 
@@ -400,9 +380,8 @@ static int ad5592r_read_raw(struct iio_dev *iio_dev,
 			read_val &= GENMASK(11, 0);
 
 		} else {
-			mutex_lock(&st->lock);
-			read_val = st->cached_dac[chan->channel];
-			mutex_unlock(&st->lock);
+			scoped_guard(mutex, &st->lock)
+				read_val = st->cached_dac[chan->channel];
 		}
 
 		dev_dbg(st->dev, "Channel %u read: 0x%04hX\n",
@@ -420,16 +399,14 @@ static int ad5592r_read_raw(struct iio_dev *iio_dev,
 			return IIO_VAL_INT_PLUS_NANO;
 		}
 
-		mutex_lock(&st->lock);
-
-		if (chan->output)
-			mult = !!(st->cached_gp_ctrl &
-				AD5592R_REG_CTRL_DAC_RANGE);
-		else
-			mult = !!(st->cached_gp_ctrl &
-				AD5592R_REG_CTRL_ADC_RANGE);
-
-		mutex_unlock(&st->lock);
+		scoped_guard(mutex, &st->lock) {
+			if (chan->output)
+				mult = !!(st->cached_gp_ctrl &
+					AD5592R_REG_CTRL_DAC_RANGE);
+			else
+				mult = !!(st->cached_gp_ctrl &
+					AD5592R_REG_CTRL_ADC_RANGE);
+		}
 
 		*val *= ++mult;
 
@@ -439,15 +416,13 @@ static int ad5592r_read_raw(struct iio_dev *iio_dev,
 	case IIO_CHAN_INFO_OFFSET:
 		ret = ad5592r_get_vref(st);
 
-		mutex_lock(&st->lock);
+		guard(mutex)(&st->lock);
 
 		if (st->cached_gp_ctrl & AD5592R_REG_CTRL_ADC_RANGE)
 			*val = (-34365 * 25) / ret;
 		else
 			*val = (-75365 * 25) / ret;
 
-		mutex_unlock(&st->lock);
-
 		return IIO_VAL_INT;
 	default:
 		return -EINVAL;

-- 
2.45.2