[PATCH v4 8/8] iio: accel: sca3000: convert to guard(mutex)

[Rajveer Chaudhari <rajveer.chaudhari.linux@gmail.com>]

Replace manual mutex_lock/mutex_unlock pair with guard(mutex) in
sca3000_print_rev(), sca3000_ring_int_process(),
sca3000_read_event_config(), __sca3000_hw_ring_state_set(),
sca3000_hw_ring_preenable(), sca3000_hw_ring_postdisable(),
sca3000_clean_setup(), sca3000_stop_all_interrupts().
This ensures the mutex is released on all return paths and
allows returning directly without a goto label.

Signed-off-by: Rajveer Chaudhari <rajveer.chaudhari.linux@gmail.com>
---
v4: No changes

v3: Fixed return statements to make it clear about good/error path.
Removed Not necessary return statement in sca3000_read_event_config().
Dropped else statement to reduce indent of the code in
sca3000_read_event_config.
Fixed indentation.

v2: Dropped Header alignment change
---
 drivers/iio/accel/sca3000.c | 138 +++++++++++++++---------------------
 1 file changed, 59 insertions(+), 79 deletions(-)

diff --git a/drivers/iio/accel/sca3000.c b/drivers/iio/accel/sca3000.c
index d61ad12aef78..9703946f133d 100644
--- a/drivers/iio/accel/sca3000.c
+++ b/drivers/iio/accel/sca3000.c
@@ -427,18 +427,18 @@ static int sca3000_print_rev(struct iio_dev *indio_dev)
 	int ret;
 	struct sca3000_state *st = iio_priv(indio_dev);
 
-	mutex_lock(&st->lock);
+	guard(mutex)(&st->lock);
+
 	ret = sca3000_read_data_short(st, SCA3000_REG_REVID_ADDR, 1);
 	if (ret < 0)
-		goto error_ret;
+		return ret;
+
 	dev_info(&indio_dev->dev,
 		 "sca3000 revision major=%lu, minor=%lu\n",
 		 st->rx[0] & SCA3000_REG_REVID_MAJOR_MASK,
 		 st->rx[0] & SCA3000_REG_REVID_MINOR_MASK);
-error_ret:
-	mutex_unlock(&st->lock);
 
-	return ret;
+	return 0;
 }
 
 static ssize_t
@@ -999,13 +999,14 @@ static void sca3000_ring_int_process(u8 val, struct iio_dev *indio_dev)
 	struct sca3000_state *st = iio_priv(indio_dev);
 	int ret, i, num_available;
 
-	mutex_lock(&st->lock);
+	guard(mutex)(&st->lock);
 
 	if (val & SCA3000_REG_INT_STATUS_HALF) {
 		ret = sca3000_read_data_short(st, SCA3000_REG_BUF_COUNT_ADDR,
 					      1);
 		if (ret)
-			goto error_ret;
+			return;
+
 		num_available = st->rx[0];
 		/*
 		 * num_available is the total number of samples available
@@ -1014,7 +1015,8 @@ static void sca3000_ring_int_process(u8 val, struct iio_dev *indio_dev)
 		ret = sca3000_read_data(st, SCA3000_REG_RING_OUT_ADDR, st->rx,
 					num_available * 2);
 		if (ret)
-			goto error_ret;
+			return;
+
 		for (i = 0; i < num_available / 3; i++) {
 			/*
 			 * Dirty hack to cover for 11 bit in fifo, 13 bit
@@ -1026,8 +1028,6 @@ static void sca3000_ring_int_process(u8 val, struct iio_dev *indio_dev)
 			iio_push_to_buffers(indio_dev, st->rx + i * 3 * 2);
 		}
 	}
-error_ret:
-	mutex_unlock(&st->lock);
 }
 
 /**
@@ -1113,16 +1113,15 @@ static int sca3000_read_event_config(struct iio_dev *indio_dev,
 	struct sca3000_state *st = iio_priv(indio_dev);
 	int ret;
 	/* read current value of mode register */
-	mutex_lock(&st->lock);
+	guard(mutex)(&st->lock);
 
 	ret = sca3000_read_data_short(st, SCA3000_REG_MODE_ADDR, 1);
 	if (ret)
-		goto error_ret;
+		return ret;
 
 	switch (chan->channel2) {
 	case IIO_MOD_X_AND_Y_AND_Z:
-		ret = !!(st->rx[0] & SCA3000_REG_MODE_FREE_FALL_DETECT);
-		break;
+		return !!(st->rx[0] & SCA3000_REG_MODE_FREE_FALL_DETECT);
 	case IIO_MOD_X:
 	case IIO_MOD_Y:
 	case IIO_MOD_Z:
@@ -1132,24 +1131,18 @@ static int sca3000_read_event_config(struct iio_dev *indio_dev,
 		 */
 		if ((st->rx[0] & SCA3000_REG_MODE_MODE_MASK)
 		    != SCA3000_REG_MODE_MEAS_MODE_MOT_DET) {
-			ret = 0;
-		} else {
-			ret = sca3000_read_ctrl_reg(st,
-						SCA3000_REG_CTRL_SEL_MD_CTRL);
-			if (ret < 0)
-				goto error_ret;
-			/* only supporting logical or's for now */
-			ret = !!(ret & sca3000_addresses[chan->address][2]);
+			return 0;
 		}
-		break;
+
+		ret = sca3000_read_ctrl_reg(st,
+					SCA3000_REG_CTRL_SEL_MD_CTRL);
+		if (ret < 0)
+			return ret;
+		/* only supporting logical or's for now */
+		return !!(ret & sca3000_addresses[chan->address][2]);
 	default:
-		ret = -EINVAL;
+		return -EINVAL;
 	}
-
-error_ret:
-	mutex_unlock(&st->lock);
-
-	return ret;
 }
 
 static int sca3000_freefall_set_state(struct iio_dev *indio_dev, bool state)
@@ -1280,23 +1273,21 @@ int __sca3000_hw_ring_state_set(struct iio_dev *indio_dev, bool state)
 	struct sca3000_state *st = iio_priv(indio_dev);
 	int ret;
 
-	mutex_lock(&st->lock);
+	guard(mutex)(&st->lock);
+
 	ret = sca3000_read_data_short(st, SCA3000_REG_MODE_ADDR, 1);
 	if (ret)
-		goto error_ret;
+		return ret;
+
 	if (state) {
 		dev_info(&indio_dev->dev, "supposedly enabling ring buffer\n");
-		ret = sca3000_write_reg(st,
+		return sca3000_write_reg(st,
 			SCA3000_REG_MODE_ADDR,
 			(st->rx[0] | SCA3000_REG_MODE_RING_BUF_ENABLE));
 	} else
-		ret = sca3000_write_reg(st,
+		return sca3000_write_reg(st,
 			SCA3000_REG_MODE_ADDR,
 			(st->rx[0] & ~SCA3000_REG_MODE_RING_BUF_ENABLE));
-error_ret:
-	mutex_unlock(&st->lock);
-
-	return ret;
 }
 
 /**
@@ -1313,26 +1304,20 @@ static int sca3000_hw_ring_preenable(struct iio_dev *indio_dev)
 	int ret;
 	struct sca3000_state *st = iio_priv(indio_dev);
 
-	mutex_lock(&st->lock);
+	guard(mutex)(&st->lock);
 
 	/* Enable the 50% full interrupt */
 	ret = sca3000_read_data_short(st, SCA3000_REG_INT_MASK_ADDR, 1);
 	if (ret)
-		goto error_unlock;
+		return ret;
+
 	ret = sca3000_write_reg(st,
 				SCA3000_REG_INT_MASK_ADDR,
 				st->rx[0] | SCA3000_REG_INT_MASK_RING_HALF);
 	if (ret)
-		goto error_unlock;
-
-	mutex_unlock(&st->lock);
+		return ret;
 
 	return __sca3000_hw_ring_state_set(indio_dev, 1);
-
-error_unlock:
-	mutex_unlock(&st->lock);
-
-	return ret;
 }
 
 static int sca3000_hw_ring_postdisable(struct iio_dev *indio_dev)
@@ -1345,17 +1330,15 @@ static int sca3000_hw_ring_postdisable(struct iio_dev *indio_dev)
 		return ret;
 
 	/* Disable the 50% full interrupt */
-	mutex_lock(&st->lock);
+	guard(mutex)(&st->lock);
 
 	ret = sca3000_read_data_short(st, SCA3000_REG_INT_MASK_ADDR, 1);
 	if (ret)
-		goto unlock;
-	ret = sca3000_write_reg(st,
-				SCA3000_REG_INT_MASK_ADDR,
-				st->rx[0] & ~SCA3000_REG_INT_MASK_RING_HALF);
-unlock:
-	mutex_unlock(&st->lock);
-	return ret;
+		return ret;
+
+	return sca3000_write_reg(st,
+				 SCA3000_REG_INT_MASK_ADDR,
+				 st->rx[0] & ~SCA3000_REG_INT_MASK_RING_HALF);
 }
 
 static const struct iio_buffer_setup_ops sca3000_ring_setup_ops = {
@@ -1375,25 +1358,26 @@ static int sca3000_clean_setup(struct sca3000_state *st)
 {
 	int ret;
 
-	mutex_lock(&st->lock);
+	guard(mutex)(&st->lock);
+
 	/* Ensure all interrupts have been acknowledged */
 	ret = sca3000_read_data_short(st, SCA3000_REG_INT_STATUS_ADDR, 1);
 	if (ret)
-		goto error_ret;
+		return ret;
 
 	/* Turn off all motion detection channels */
 	ret = sca3000_read_ctrl_reg(st, SCA3000_REG_CTRL_SEL_MD_CTRL);
 	if (ret < 0)
-		goto error_ret;
+		return ret;
 	ret = sca3000_write_ctrl_reg(st, SCA3000_REG_CTRL_SEL_MD_CTRL,
 				     ret & SCA3000_MD_CTRL_PROT_MASK);
 	if (ret)
-		goto error_ret;
+		return ret;
 
 	/* Disable ring buffer */
 	ret = sca3000_read_ctrl_reg(st, SCA3000_REG_CTRL_SEL_OUT_CTRL);
 	if (ret < 0)
-		goto error_ret;
+		return ret;
 	ret = sca3000_write_ctrl_reg(st, SCA3000_REG_CTRL_SEL_OUT_CTRL,
 				     (ret & SCA3000_REG_OUT_CTRL_PROT_MASK)
 				     | SCA3000_REG_OUT_CTRL_BUF_X_EN
@@ -1401,17 +1385,17 @@ static int sca3000_clean_setup(struct sca3000_state *st)
 				     | SCA3000_REG_OUT_CTRL_BUF_Z_EN
 				     | SCA3000_REG_OUT_CTRL_BUF_DIV_4);
 	if (ret)
-		goto error_ret;
+		return ret;
 	/* Enable interrupts, relevant to mode and set up as active low */
 	ret = sca3000_read_data_short(st, SCA3000_REG_INT_MASK_ADDR, 1);
 	if (ret)
-		goto error_ret;
+		return ret;
 	ret = sca3000_write_reg(st,
 				SCA3000_REG_INT_MASK_ADDR,
 				(ret & SCA3000_REG_INT_MASK_PROT_MASK)
 				| SCA3000_REG_INT_MASK_ACTIVE_LOW);
 	if (ret)
-		goto error_ret;
+		return ret;
 	/*
 	 * Select normal measurement mode, free fall off, ring off
 	 * Ring in 12 bit mode - it is fine to overwrite reserved bits 3,5
@@ -1419,13 +1403,10 @@ static int sca3000_clean_setup(struct sca3000_state *st)
 	 */
 	ret = sca3000_read_data_short(st, SCA3000_REG_MODE_ADDR, 1);
 	if (ret)
-		goto error_ret;
-	ret = sca3000_write_reg(st, SCA3000_REG_MODE_ADDR,
-				(st->rx[0] & SCA3000_MODE_PROT_MASK));
+		return ret;
 
-error_ret:
-	mutex_unlock(&st->lock);
-	return ret;
+	return sca3000_write_reg(st, SCA3000_REG_MODE_ADDR,
+				(st->rx[0] & SCA3000_MODE_PROT_MASK));
 }
 
 static const struct iio_info sca3000_info = {
@@ -1507,18 +1488,17 @@ static int sca3000_stop_all_interrupts(struct sca3000_state *st)
 {
 	int ret;
 
-	mutex_lock(&st->lock);
+	guard(mutex)(&st->lock);
+
 	ret = sca3000_read_data_short(st, SCA3000_REG_INT_MASK_ADDR, 1);
 	if (ret)
-		goto error_ret;
-	ret = sca3000_write_reg(st, SCA3000_REG_INT_MASK_ADDR,
-				(st->rx[0] &
-				 ~(SCA3000_REG_INT_MASK_RING_THREE_QUARTER |
-				   SCA3000_REG_INT_MASK_RING_HALF |
-				   SCA3000_REG_INT_MASK_ALL_INTS)));
-error_ret:
-	mutex_unlock(&st->lock);
-	return ret;
+		return ret;
+
+	return sca3000_write_reg(st, SCA3000_REG_INT_MASK_ADDR,
+				 (st->rx[0] &
+				  ~(SCA3000_REG_INT_MASK_RING_THREE_QUARTER |
+				    SCA3000_REG_INT_MASK_RING_HALF |
+				    SCA3000_REG_INT_MASK_ALL_INTS)));
 }
 
 static void sca3000_remove(struct spi_device *spi)
-- 
2.53.0