[PATCH] gpio: twl4030: Use guard(mutex)() over manual locking

[Maxwell Doose]

Replace mutex_lock() and mutex_unlock() pairs with the RAII macro
guard(mutex)(). This keeps the driver up-to-date with the latest
function macros.

Remove now-redundant gotos and goto labels which will maintain
readability. In addition, replace some gotos with direct returns where
appropriate.

Update certain control paths to make them more suited to the new
locking.

Signed-off-by: Maxwell Doose <m32285159@xxxxxxxxx>
---
 drivers/gpio/gpio-twl4030.c | 69 ++++++++++++++-----------------------
 1 file changed, 26 insertions(+), 43 deletions(-)

diff --git a/drivers/gpio/gpio-twl4030.c b/drivers/gpio/gpio-twl4030.c
index a851702befde..df17f9c08817 100644
--- a/drivers/gpio/gpio-twl4030.c
+++ b/drivers/gpio/gpio-twl4030.c
@@ -23,6 +23,7 @@
 #include <linux/platform_device.h>
 #include <linux/of.h>
 #include <linux/irqdomain.h>
+#include <linux/cleanup.h>
 
 #include <linux/mfd/twl.h>
 
@@ -209,7 +210,7 @@ static int twl_request(struct gpio_chip *chip, unsigned offset)
 	struct gpio_twl4030_priv *priv = gpiochip_get_data(chip);
 	int status = 0;
 
-	mutex_lock(&priv->mutex);
+	guard(mutex)(&priv->mutex);
 
 	/* Support the two LED outputs as output-only GPIOs. */
 	if (offset >= TWL4030_GPIO_MAX) {
@@ -227,30 +228,29 @@ static int twl_request(struct gpio_chip *chip, unsigned offset)
 		/* Configure PWM OFF register first */
 		status = twl_i2c_write_u8(TWL4030_MODULE_LED, 0x7f, reg + 1);
 		if (status < 0)
-			goto done;
+			return status;
 
 		/* Followed by PWM ON register */
 		status = twl_i2c_write_u8(TWL4030_MODULE_LED, 0x7f, reg);
 		if (status < 0)
-			goto done;
+			return status;
 
 		/* init LED to not-driven (high) */
 		status = twl_i2c_read_u8(TWL4030_MODULE_LED, &cached_leden,
 					 TWL4030_LED_LEDEN_REG);
 		if (status < 0)
-			goto done;
+			return status;
 		cached_leden &= ~ledclr_mask;
 		status = twl_i2c_write_u8(TWL4030_MODULE_LED, cached_leden,
 					  TWL4030_LED_LEDEN_REG);
 		if (status < 0)
-			goto done;
+			return status;
 
 		status = 0;
-		goto done;
 	}
 
 	/* on first use, turn GPIO module "on" */
-	if (!priv->usage_count) {
+	else if (!priv->usage_count) {
 		struct twl4030_gpio_platform_data *pdata;
 		u8 value = MASK_GPIO_CTRL_GPIO_ON;
 
@@ -264,11 +264,9 @@ static int twl_request(struct gpio_chip *chip, unsigned offset)
 		status = gpio_twl4030_write(REG_GPIO_CTRL, value);
 	}
 
-done:
 	if (!status)
 		priv->usage_count |= BIT(offset);
 
-	mutex_unlock(&priv->mutex);
 	return status;
 }
 
@@ -276,10 +274,10 @@ static void twl_free(struct gpio_chip *chip, unsigned offset)
 {
 	struct gpio_twl4030_priv *priv = gpiochip_get_data(chip);
 
-	mutex_lock(&priv->mutex);
+	guard(mutex)(&priv->mutex);
 	if (offset >= TWL4030_GPIO_MAX) {
 		WARN_ON_ONCE(twl4030_led_set_value(offset - TWL4030_GPIO_MAX, 1));
-		goto out;
+		return;
 	}
 
 	priv->usage_count &= ~BIT(offset);
@@ -287,9 +285,6 @@ static void twl_free(struct gpio_chip *chip, unsigned offset)
 	/* on last use, switch off GPIO module */
 	if (!priv->usage_count)
 		gpio_twl4030_write(REG_GPIO_CTRL, 0x0);
-
-out:
-	mutex_unlock(&priv->mutex);
 }
 
 static int twl_direction_in(struct gpio_chip *chip, unsigned offset)
@@ -297,17 +292,15 @@ static int twl_direction_in(struct gpio_chip *chip, unsigned offset)
 	struct gpio_twl4030_priv *priv = gpiochip_get_data(chip);
 	int ret;
 
-	mutex_lock(&priv->mutex);
+	guard(mutex)(&priv->mutex);
 	if (offset < TWL4030_GPIO_MAX)
 		ret = twl4030_set_gpio_direction(offset, 1);
 	else
-		ret = -EINVAL;	/* LED outputs can't be set as input */
+		return -EINVAL;	/* LED outputs can't be set as input */
 
 	if (!ret)
 		priv->direction &= ~BIT(offset);
 
-	mutex_unlock(&priv->mutex);
-
 	return ret;
 }
 
@@ -317,10 +310,9 @@ static int twl_get(struct gpio_chip *chip, unsigned offset)
 	int ret;
 	int status = 0;
 
-	mutex_lock(&priv->mutex);
+	guard(mutex)(&priv->mutex);
 	if (!(priv->usage_count & BIT(offset))) {
-		ret = -EPERM;
-		goto out;
+		return -EPERM;
 	}
 
 	if (priv->direction & BIT(offset))
@@ -328,10 +320,7 @@ static int twl_get(struct gpio_chip *chip, unsigned offset)
 	else
 		status = twl4030_get_gpio_datain(offset);
 
-	ret = (status < 0) ? status : !!status;
-out:
-	mutex_unlock(&priv->mutex);
-	return ret;
+	return (status < 0) ? status : !!status;
 }
 
 static int twl_set(struct gpio_chip *chip, unsigned int offset, int value)
@@ -339,7 +328,7 @@ static int twl_set(struct gpio_chip *chip, unsigned int offset, int value)
 	struct gpio_twl4030_priv *priv = gpiochip_get_data(chip);
 	int ret;
 
-	mutex_lock(&priv->mutex);
+	guard(mutex)(&priv->mutex);
 	if (offset < TWL4030_GPIO_MAX)
 		ret = twl4030_set_gpio_dataout(offset, value);
 	else
@@ -350,8 +339,6 @@ static int twl_set(struct gpio_chip *chip, unsigned int offset, int value)
 	else
 		priv->out_state &= ~BIT(offset);
 
-	mutex_unlock(&priv->mutex);
-
 	return ret;
 }
 
@@ -360,21 +347,19 @@ static int twl_direction_out(struct gpio_chip *chip, unsigned offset, int value)
 	struct gpio_twl4030_priv *priv = gpiochip_get_data(chip);
 	int ret = 0;
 
-	mutex_lock(&priv->mutex);
-	if (offset < TWL4030_GPIO_MAX) {
-		ret = twl4030_set_gpio_direction(offset, 0);
-		if (ret) {
-			mutex_unlock(&priv->mutex);
-			return ret;
+	scoped_guard(mutex, &priv->mutex) {
+		if (offset < TWL4030_GPIO_MAX) {
+			ret = twl4030_set_gpio_direction(offset, 0);
+			if (ret)
+				return ret;
 		}
-	}
 
-	/*
-	 *  LED gpios i.e. offset >= TWL4030_GPIO_MAX are always output
-	 */
+		/*
+		 *  LED gpios i.e. offset >= TWL4030_GPIO_MAX are always output
+		 */
 
-	priv->direction |= BIT(offset);
-	mutex_unlock(&priv->mutex);
+		priv->direction |= BIT(offset);
+	}
 
 	return twl_set(chip, offset, value);
 }
@@ -388,15 +373,13 @@ static int twl_get_direction(struct gpio_chip *chip, unsigned offset)
 	 */
 	int ret = GPIO_LINE_DIRECTION_OUT;
 
-	mutex_lock(&priv->mutex);
+	guard(mutex)(&priv->mutex);
 	if (offset < TWL4030_GPIO_MAX) {
 		ret = twl4030_get_gpio_direction(offset);
 		if (ret) {
-			mutex_unlock(&priv->mutex);
 			return ret;
 		}
 	}
-	mutex_unlock(&priv->mutex);
 
 	return ret;
 }
-- 
2.53.0