[PATCH v2 1/2] gpio: adnp: use lock guards for the I2C lock

[Bartosz Golaszewski <brgl@bgdev.pl>]

From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Reduce the code complexity by using automatic lock guards with the I2C
mutex.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
---
 drivers/gpio/gpio-adnp.c | 122 +++++++++++++++++++----------------------------
 1 file changed, 49 insertions(+), 73 deletions(-)

diff --git a/drivers/gpio/gpio-adnp.c b/drivers/gpio/gpio-adnp.c
index 6dafab0cf964..1a282cba8489 100644
--- a/drivers/gpio/gpio-adnp.c
+++ b/drivers/gpio/gpio-adnp.c
@@ -3,6 +3,7 @@
  * Copyright (C) 2011-2012 Avionic Design GmbH
  */
 
+#include <linux/cleanup.h>
 #include <linux/gpio/driver.h>
 #include <linux/i2c.h>
 #include <linux/interrupt.h>
@@ -101,9 +102,9 @@ static void adnp_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
 {
 	struct adnp *adnp = gpiochip_get_data(chip);
 
-	mutex_lock(&adnp->i2c_lock);
+	guard(mutex)(&adnp->i2c_lock);
+
 	__adnp_gpio_set(adnp, offset, value);
-	mutex_unlock(&adnp->i2c_lock);
 }
 
 static int adnp_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
@@ -114,32 +115,26 @@ static int adnp_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
 	u8 value;
 	int err;
 
-	mutex_lock(&adnp->i2c_lock);
+	guard(mutex)(&adnp->i2c_lock);
 
 	err = adnp_read(adnp, GPIO_DDR(adnp) + reg, &value);
 	if (err < 0)
-		goto out;
+		return err;
 
 	value &= ~BIT(pos);
 
 	err = adnp_write(adnp, GPIO_DDR(adnp) + reg, value);
 	if (err < 0)
-		goto out;
+		return err;
 
 	err = adnp_read(adnp, GPIO_DDR(adnp) + reg, &value);
 	if (err < 0)
-		goto out;
+		return err;
 
-	if (value & BIT(pos)) {
-		err = -EPERM;
-		goto out;
-	}
+	if (value & BIT(pos))
+		return -EPERM;
 
-	err = 0;
-
-out:
-	mutex_unlock(&adnp->i2c_lock);
-	return err;
+	return 0;
 }
 
 static int adnp_gpio_direction_output(struct gpio_chip *chip, unsigned offset,
@@ -151,33 +146,28 @@ static int adnp_gpio_direction_output(struct gpio_chip *chip, unsigned offset,
 	int err;
 	u8 val;
 
-	mutex_lock(&adnp->i2c_lock);
+	guard(mutex)(&adnp->i2c_lock);
 
 	err = adnp_read(adnp, GPIO_DDR(adnp) + reg, &val);
 	if (err < 0)
-		goto out;
+		return err;
 
 	val |= BIT(pos);
 
 	err = adnp_write(adnp, GPIO_DDR(adnp) + reg, val);
 	if (err < 0)
-		goto out;
+		return err;
 
 	err = adnp_read(adnp, GPIO_DDR(adnp) + reg, &val);
 	if (err < 0)
-		goto out;
+		return err;
 
-	if (!(val & BIT(pos))) {
-		err = -EPERM;
-		goto out;
-	}
+	if (!(val & BIT(pos)))
+		return -EPERM;
 
 	__adnp_gpio_set(adnp, offset, value);
-	err = 0;
 
-out:
-	mutex_unlock(&adnp->i2c_lock);
-	return err;
+	return 0;
 }
 
 static void adnp_gpio_dbg_show(struct seq_file *s, struct gpio_chip *chip)
@@ -187,27 +177,26 @@ static void adnp_gpio_dbg_show(struct seq_file *s, struct gpio_chip *chip)
 	int err;
 
 	for (i = 0; i < num_regs; i++) {
-		u8 ddr, plr, ier, isr;
+		u8 ddr = 0, plr = 0, ier = 0, isr = 0;
 
-		mutex_lock(&adnp->i2c_lock);
+		scoped_guard(mutex, &adnp->i2c_lock) {
+			err = adnp_read(adnp, GPIO_DDR(adnp) + i, &ddr);
+			if (err < 0)
+				return;
 
-		err = adnp_read(adnp, GPIO_DDR(adnp) + i, &ddr);
-		if (err < 0)
-			goto unlock;
+			err = adnp_read(adnp, GPIO_PLR(adnp) + i, &plr);
+			if (err < 0)
+				return;
 
-		err = adnp_read(adnp, GPIO_PLR(adnp) + i, &plr);
-		if (err < 0)
-			goto unlock;
+			err = adnp_read(adnp, GPIO_IER(adnp) + i, &ier);
+			if (err < 0)
+				return;
 
-		err = adnp_read(adnp, GPIO_IER(adnp) + i, &ier);
-		if (err < 0)
-			goto unlock;
+			err = adnp_read(adnp, GPIO_ISR(adnp) + i, &isr);
+			if (err < 0)
+				return;
 
-		err = adnp_read(adnp, GPIO_ISR(adnp) + i, &isr);
-		if (err < 0)
-			goto unlock;
-
-		mutex_unlock(&adnp->i2c_lock);
+		}
 
 		for (j = 0; j < 8; j++) {
 			unsigned int bit = (i << adnp->reg_shift) + j;
@@ -232,11 +221,6 @@ static void adnp_gpio_dbg_show(struct seq_file *s, struct gpio_chip *chip)
 				   direction, level, interrupt, pending);
 		}
 	}
-
-	return;
-
-unlock:
-	mutex_unlock(&adnp->i2c_lock);
 }
 
 static irqreturn_t adnp_irq(int irq, void *data)
@@ -248,32 +232,24 @@ static irqreturn_t adnp_irq(int irq, void *data)
 
 	for (i = 0; i < num_regs; i++) {
 		unsigned int base = i << adnp->reg_shift, bit;
-		u8 changed, level, isr, ier;
+		u8 changed, level = 0, isr = 0, ier = 0;
 		unsigned long pending;
 		int err;
 
-		mutex_lock(&adnp->i2c_lock);
+		scoped_guard(mutex, &adnp->i2c_lock) {
+			err = adnp_read(adnp, GPIO_PLR(adnp) + i, &level);
+			if (err < 0)
+				continue;
 
-		err = adnp_read(adnp, GPIO_PLR(adnp) + i, &level);
-		if (err < 0) {
-			mutex_unlock(&adnp->i2c_lock);
-			continue;
+			err = adnp_read(adnp, GPIO_ISR(adnp) + i, &isr);
+			if (err < 0)
+				continue;
+
+			err = adnp_read(adnp, GPIO_IER(adnp) + i, &ier);
+			if (err < 0)
+				continue;
 		}
 
-		err = adnp_read(adnp, GPIO_ISR(adnp) + i, &isr);
-		if (err < 0) {
-			mutex_unlock(&adnp->i2c_lock);
-			continue;
-		}
-
-		err = adnp_read(adnp, GPIO_IER(adnp) + i, &ier);
-		if (err < 0) {
-			mutex_unlock(&adnp->i2c_lock);
-			continue;
-		}
-
-		mutex_unlock(&adnp->i2c_lock);
-
 		/* determine pins that changed levels */
 		changed = level ^ adnp->irq_level[i];
 
@@ -365,12 +341,12 @@ static void adnp_irq_bus_unlock(struct irq_data *d)
 	struct adnp *adnp = gpiochip_get_data(gc);
 	unsigned int num_regs = 1 << adnp->reg_shift, i;
 
-	mutex_lock(&adnp->i2c_lock);
+	scoped_guard(mutex, &adnp->i2c_lock) {
+		for (i = 0; i < num_regs; i++)
+			adnp_write(adnp, GPIO_IER(adnp) + i,
+				   adnp->irq_enable[i]);
+	}
 
-	for (i = 0; i < num_regs; i++)
-		adnp_write(adnp, GPIO_IER(adnp) + i, adnp->irq_enable[i]);
-
-	mutex_unlock(&adnp->i2c_lock);
 	mutex_unlock(&adnp->irq_lock);
 }
 

-- 
2.45.2