iio: adc: ad7768-1: use guard(mutex) to simplify code

Use guard(mutex) from cleanup.h to remove most of the gotos and to make
the code simpler and less likely to fail due to forgetting to unlock
the resources.

Signed-off-by: Jonathan Santos <Jonathan.Santos@analog.com>

Author: jonathanns

drivers/iio/adc/ad7768-1.c

@@ -5,6 +5,7 @@
  * Copyright 2017 Analog Devices Inc.
  */
 #include <linux/bitfield.h>
+#include <linux/cleanup.h>
 #include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/device.h>
@@ -340,20 +341,12 @@ static int ad7768_reg_access(struct iio_dev *indio_dev,
 			     unsigned int *readval)
 {
 	struct ad7768_state *st = iio_priv(indio_dev);
-	int ret;
 
-	mutex_lock(&st->lock);
-	if (readval) {
-		ret = ad7768_spi_reg_read(st, reg, readval, 1);
-		if (ret < 0)
-			goto err_unlock;
-	} else {
-		ret = ad7768_spi_reg_write(st, reg, writeval);
-	}
-err_unlock:
-	mutex_unlock(&st->lock);
+	guard(mutex)(&st->lock);
+	if (readval)
+		return ad7768_spi_reg_read(st, reg, readval, 1);
 
-	return ret;
+	return ad7768_spi_reg_write(st, reg, writeval);
 }
 
 static int ad7768_set_dig_fil(struct ad7768_state *st,
@@ -381,32 +374,24 @@ static int ad7768_set_dig_fil(struct ad7768_state *st,
 int ad7768_gpio_direction_input(struct gpio_chip *chip, unsigned int offset)
 {
 	struct ad7768_state *st = gpiochip_get_data(chip);
-	int ret;
 
-	mutex_lock(&st->lock);
-	ret = ad7768_spi_reg_write_masked(st,
+	guard(mutex)(&st->lock);
+	return ad7768_spi_reg_write_masked(st,
 					  AD7768_REG_GPIO_CONTROL,
 					  BIT(offset),
 					  AD7768_GPIO_INPUT(offset));
-	mutex_unlock(&st->lock);
-
-	return ret;
 }
 
 int ad7768_gpio_direction_output(struct gpio_chip *chip,
 				 unsigned int offset, int value)
 {
 	struct ad7768_state *st = gpiochip_get_data(chip);
-	int ret;
 
-	mutex_lock(&st->lock);
-	ret = ad7768_spi_reg_write_masked(st,
+	guard(mutex)(&st->lock);
+	return ad7768_spi_reg_write_masked(st,
 					  AD7768_REG_GPIO_CONTROL,
 					  BIT(offset),
 					  AD7768_GPIO_OUTPUT(offset));
-	mutex_unlock(&st->lock);
-
-	return ret;
 }
 
 int ad7768_gpio_get(struct gpio_chip *chip, unsigned int offset)
@@ -415,24 +400,19 @@ int ad7768_gpio_get(struct gpio_chip *chip, unsigned int offset)
 	unsigned int val;
 	int ret;
 
-	mutex_lock(&st->lock);
+	guard(mutex)(&st->lock);
 	ret = ad7768_spi_reg_read(st, AD7768_REG_GPIO_CONTROL, &val, 1);
 	if (ret < 0)
-		goto gpio_get_err;
+		return ret;
 
 	if (val & BIT(offset))
 		ret = ad7768_spi_reg_read(st, AD7768_REG_GPIO_WRITE, &val, 1);
 	else
 		ret = ad7768_spi_reg_read(st, AD7768_REG_GPIO_READ, &val, 1);
 	if (ret < 0)
-		goto gpio_get_err;
-
-	ret = !!(val & BIT(offset));
-
-gpio_get_err:
-	mutex_unlock(&st->lock);
+		return ret;
 
-	return ret;
+	return !!(val & BIT(offset));
 }
 
 void ad7768_gpio_set(struct gpio_chip *chip, unsigned int offset, int value)
@@ -441,19 +421,16 @@ void ad7768_gpio_set(struct gpio_chip *chip, unsigned int offset, int value)
 	unsigned int val;
 	int ret;
 
-	mutex_lock(&st->lock);
+	guard(mutex)(&st->lock);
 	ret = ad7768_spi_reg_read(st, AD7768_REG_GPIO_CONTROL, &val, 1);
 	if (ret < 0)
-		goto gpio_set_err;
+		return;
 
 	if (val & BIT(offset))
 		ad7768_spi_reg_write_masked(st,
 					    AD7768_REG_GPIO_WRITE,
 					    BIT(offset),
 					    (value << offset));
-
-gpio_set_err:
-	mutex_unlock(&st->lock);
 }
 
 int ad7768_gpio_request(struct gpio_chip *chip, unsigned int offset)
@@ -712,7 +689,7 @@ static irqreturn_t ad7768_trigger_handler(int irq, void *p)
 	struct ad7768_state *st = iio_priv(indio_dev);
 	int ret;
 
-	mutex_lock(&st->lock);
+	guard(mutex)(&st->lock);
 
 	ret = spi_read(st->spi, &st->data.scan.chan, 3);
 	if (ret < 0)
@@ -723,7 +700,6 @@ static irqreturn_t ad7768_trigger_handler(int irq, void *p)
 
 err_unlock:
 	iio_trigger_notify_done(indio_dev->trig);
-	mutex_unlock(&st->lock);
 
 	return IRQ_HANDLED;
 }