[PATCH v2] iio: adc: mcp3911: simplify code with guard macro

[Marcus Folkesson <marcus.folkesson@gmail.com>]

Use the guard(mutex) macro for handle mutex lock/unlocks.

Signed-off-by: Marcus Folkesson <marcus.folkesson@gmail.com>
---
Changes in v2:
- Return directly instead of goto label
- Link to v1: https://lore.kernel.org/r/20231125-mcp3911-guard-v1-1-2748d16a3f3f@gmail.com
---
 drivers/iio/adc/mcp3911.c | 27 ++++++++++-----------------
 1 file changed, 10 insertions(+), 17 deletions(-)

diff --git a/drivers/iio/adc/mcp3911.c b/drivers/iio/adc/mcp3911.c
index 974c5bd923a6..30836725ef9a 100644
--- a/drivers/iio/adc/mcp3911.c
+++ b/drivers/iio/adc/mcp3911.c
@@ -7,6 +7,7 @@
  */
 #include <linux/bitfield.h>
 #include <linux/bits.h>
+#include <linux/cleanup.h>
 #include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/err.h>
@@ -168,13 +169,13 @@ static int mcp3911_read_raw(struct iio_dev *indio_dev,
 	struct mcp3911 *adc = iio_priv(indio_dev);
 	int ret = -EINVAL;
 
-	mutex_lock(&adc->lock);
+	guard(mutex)(&adc->lock);
 	switch (mask) {
 	case IIO_CHAN_INFO_RAW:
 		ret = mcp3911_read(adc,
 				   MCP3911_CHANNEL(channel->channel), val, 3);
 		if (ret)
-			goto out;
+			return ret;
 
 		*val = sign_extend32(*val, 23);
 
@@ -185,14 +186,14 @@ static int mcp3911_read_raw(struct iio_dev *indio_dev,
 		ret = mcp3911_read(adc,
 				   MCP3911_OFFCAL(channel->channel), val, 3);
 		if (ret)
-			goto out;
+			return ret;
 
 		ret = IIO_VAL_INT;
 		break;
 	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
 		ret = mcp3911_read(adc, MCP3911_REG_CONFIG, val, 2);
 		if (ret)
-			goto out;
+			return ret;
 
 		*val = FIELD_GET(MCP3911_CONFIG_OSR, *val);
 		*val = 32 << *val;
@@ -206,8 +207,6 @@ static int mcp3911_read_raw(struct iio_dev *indio_dev,
 		break;
 	}
 
-out:
-	mutex_unlock(&adc->lock);
 	return ret;
 }
 
@@ -218,7 +217,7 @@ static int mcp3911_write_raw(struct iio_dev *indio_dev,
 	struct mcp3911 *adc = iio_priv(indio_dev);
 	int ret = -EINVAL;
 
-	mutex_lock(&adc->lock);
+	guard(mutex)(&adc->lock);
 	switch (mask) {
 	case IIO_CHAN_INFO_SCALE:
 		for (int i = 0; i < MCP3911_NUM_SCALES; i++) {
@@ -233,16 +232,14 @@ static int mcp3911_write_raw(struct iio_dev *indio_dev,
 		}
 		break;
 	case IIO_CHAN_INFO_OFFSET:
-		if (val2 != 0) {
-			ret = -EINVAL;
-			goto out;
-		}
+		if (val2 != 0)
+			return -EINVAL;
 
 		/* Write offset */
 		ret = mcp3911_write(adc, MCP3911_OFFCAL(channel->channel), val,
 				    3);
 		if (ret)
-			goto out;
+			return ret;
 
 		/* Enable offset*/
 		ret = mcp3911_update(adc, MCP3911_REG_STATUSCOM,
@@ -261,9 +258,6 @@ static int mcp3911_write_raw(struct iio_dev *indio_dev,
 		}
 		break;
 	}
-
-out:
-	mutex_unlock(&adc->lock);
 	return ret;
 }
 
@@ -350,7 +344,7 @@ static irqreturn_t mcp3911_trigger_handler(int irq, void *p)
 	int i = 0;
 	int ret;
 
-	mutex_lock(&adc->lock);
+	guard(mutex)(&adc->lock);
 	adc->tx_buf = MCP3911_REG_READ(MCP3911_CHANNEL(0), adc->dev_addr);
 	ret = spi_sync_transfer(adc->spi, xfer, ARRAY_SIZE(xfer));
 	if (ret < 0) {
@@ -368,7 +362,6 @@ static irqreturn_t mcp3911_trigger_handler(int irq, void *p)
 	iio_push_to_buffers_with_timestamp(indio_dev, &adc->scan,
 					   iio_get_time_ns(indio_dev));
 out:
-	mutex_unlock(&adc->lock);
 	iio_trigger_notify_done(indio_dev->trig);
 
 	return IRQ_HANDLED;

---
base-commit: ffc253263a1375a65fa6c9f62a893e9767fbebfa
change-id: 20231125-mcp3911-guard-866591e2c947

Best regards,
-- 
Marcus Folkesson <marcus.folkesson@gmail.com>