[PATCH v3 3/6] iio: adc: ti-ads7950: switch to using guard() notation

[Dmitry Torokhov]

guard() notation allows early returns when encountering errors, making
control flow more obvious. Use it.

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
---
 drivers/iio/adc/ti-ads7950.c | 75 ++++++++++++++++----------------------------
 1 file changed, 27 insertions(+), 48 deletions(-)

diff --git a/drivers/iio/adc/ti-ads7950.c b/drivers/iio/adc/ti-ads7950.c
index cdc624889559..1515089dd759 100644
--- a/drivers/iio/adc/ti-ads7950.c
+++ b/drivers/iio/adc/ti-ads7950.c
@@ -308,16 +308,17 @@ static irqreturn_t ti_ads7950_trigger_handler(int irq, void *p)
 	struct ti_ads7950_state *st = iio_priv(indio_dev);
 	int ret;
 
-	mutex_lock(&st->slock);
-	ret = spi_sync(st->spi, &st->ring_msg);
-	if (ret < 0)
-		goto out;
+	do {
+		guard(mutex)(&st->slock);
 
-	iio_push_to_buffers_with_timestamp(indio_dev, &st->rx_buf[2],
-					   iio_get_time_ns(indio_dev));
+		ret = spi_sync(st->spi, &st->ring_msg);
+		if (ret)
+			break;
+
+		iio_push_to_buffers_with_timestamp(indio_dev, &st->rx_buf[2],
+						   iio_get_time_ns(indio_dev));
+	} while (0);
 
-out:
-	mutex_unlock(&st->slock);
 	iio_trigger_notify_done(indio_dev->trig);
 
 	return IRQ_HANDLED;
@@ -328,20 +329,16 @@ static int ti_ads7950_scan_direct(struct iio_dev *indio_dev, unsigned int ch)
 	struct ti_ads7950_state *st = iio_priv(indio_dev);
 	int ret, cmd;
 
-	mutex_lock(&st->slock);
+	guard(mutex)(&st->slock);
+
 	cmd = TI_ADS7950_MAN_CMD(TI_ADS7950_CR_CHAN(ch));
 	st->single_tx = cmd;
 
 	ret = spi_sync(st->spi, &st->scan_single_msg);
 	if (ret)
-		goto out;
-
-	ret = st->single_rx;
-
-out:
-	mutex_unlock(&st->slock);
+		return ret;
 
-	return ret;
+	return st->single_rx;
 }
 
 static int ti_ads7950_get_range(struct ti_ads7950_state *st)
@@ -407,9 +404,8 @@ static int ti_ads7950_set(struct gpio_chip *chip, unsigned int offset,
 			  int value)
 {
 	struct ti_ads7950_state *st = gpiochip_get_data(chip);
-	int ret;
 
-	mutex_lock(&st->slock);
+	guard(mutex)(&st->slock);
 
 	if (value)
 		st->cmd_settings_bitmask |= BIT(offset);
@@ -417,11 +413,8 @@ static int ti_ads7950_set(struct gpio_chip *chip, unsigned int offset,
 		st->cmd_settings_bitmask &= ~BIT(offset);
 
 	st->single_tx = TI_ADS7950_MAN_CMD_SETTINGS(st);
-	ret = spi_sync(st->spi, &st->scan_single_msg);
-
-	mutex_unlock(&st->slock);
 
-	return ret;
+	return spi_sync(st->spi, &st->scan_single_msg);
 }
 
 static int ti_ads7950_get(struct gpio_chip *chip, unsigned int offset)
@@ -430,13 +423,12 @@ static int ti_ads7950_get(struct gpio_chip *chip, unsigned int offset)
 	bool state;
 	int ret;
 
-	mutex_lock(&st->slock);
+	guard(mutex)(&st->slock);
 
 	/* If set as output, return the output */
 	if (st->gpio_cmd_settings_bitmask & BIT(offset)) {
 		state = st->cmd_settings_bitmask & BIT(offset);
-		ret = 0;
-		goto out;
+		return state;
 	}
 
 	/* GPIO data bit sets SDO bits 12-15 to GPIO input */
@@ -444,7 +436,7 @@ static int ti_ads7950_get(struct gpio_chip *chip, unsigned int offset)
 	st->single_tx = TI_ADS7950_MAN_CMD_SETTINGS(st);
 	ret = spi_sync(st->spi, &st->scan_single_msg);
 	if (ret)
-		goto out;
+		return ret;
 
 	state = (st->single_rx >> 12) & BIT(offset);
 
@@ -453,12 +445,9 @@ static int ti_ads7950_get(struct gpio_chip *chip, unsigned int offset)
 	st->single_tx = TI_ADS7950_MAN_CMD_SETTINGS(st);
 	ret = spi_sync(st->spi, &st->scan_single_msg);
 	if (ret)
-		goto out;
-
-out:
-	mutex_unlock(&st->slock);
+		return ret;
 
-	return ret ?: state;
+	return state;
 }
 
 static int ti_ads7950_get_direction(struct gpio_chip *chip,
@@ -474,9 +463,8 @@ static int _ti_ads7950_set_direction(struct gpio_chip *chip, int offset,
 				     int input)
 {
 	struct ti_ads7950_state *st = gpiochip_get_data(chip);
-	int ret = 0;
 
-	mutex_lock(&st->slock);
+	guard(mutex)(&st->slock);
 
 	/* Only change direction if needed */
 	if (input && (st->gpio_cmd_settings_bitmask & BIT(offset)))
@@ -484,15 +472,11 @@ static int _ti_ads7950_set_direction(struct gpio_chip *chip, int offset,
 	else if (!input && !(st->gpio_cmd_settings_bitmask & BIT(offset)))
 		st->gpio_cmd_settings_bitmask |= BIT(offset);
 	else
-		goto out;
+		return 0;
 
 	st->single_tx = TI_ADS7950_GPIO_CMD_SETTINGS(st);
-	ret = spi_sync(st->spi, &st->scan_single_msg);
 
-out:
-	mutex_unlock(&st->slock);
-
-	return ret;
+	return spi_sync(st->spi, &st->scan_single_msg);
 }
 
 static int ti_ads7950_direction_input(struct gpio_chip *chip,
@@ -515,9 +499,9 @@ static int ti_ads7950_direction_output(struct gpio_chip *chip,
 
 static int ti_ads7950_init_hw(struct ti_ads7950_state *st)
 {
-	int ret = 0;
+	int ret;
 
-	mutex_lock(&st->slock);
+	guard(mutex)(&st->slock);
 
 	/* Settings for Manual/Auto1/Auto2 commands */
 	/* Default to 5v ref */
@@ -525,17 +509,12 @@ static int ti_ads7950_init_hw(struct ti_ads7950_state *st)
 	st->single_tx = TI_ADS7950_MAN_CMD_SETTINGS(st);
 	ret = spi_sync(st->spi, &st->scan_single_msg);
 	if (ret)
-		goto out;
+		return ret;
 
 	/* Settings for GPIO command */
 	st->gpio_cmd_settings_bitmask = 0x0;
 	st->single_tx = TI_ADS7950_GPIO_CMD_SETTINGS(st);
-	ret = spi_sync(st->spi, &st->scan_single_msg);
-
-out:
-	mutex_unlock(&st->slock);
-
-	return ret;
+	return spi_sync(st->spi, &st->scan_single_msg);
 }
 
 static int ti_ads7950_probe(struct spi_device *spi)

-- 
2.53.0.473.g4a7958ca14-goog