[PATCH v5] iio: trigger: stm32-timer-trigger: Add check for clk_enable()

[Jiasheng Jiang <jiashengjiangcool@xxxxxxxxx>]

Add check for the return value of clk_enable() in order to catch the
potential exception.

Reviewed-by: David Lechner <dlechner@xxxxxxxxxxxx>
Signed-off-by: Jiasheng Jiang <jiashengjiangcool@xxxxxxxxx>
---
Changelog:

v4 -> v5:

1. Add a default in the switch.

v3 -> v4:

1. Place braces around the case body.

v2 -> v3:

1. Use guard() to simplify the resulting code.

v1 -> v2:

1. Remove unsuitable dev_err_probe().
---
 drivers/iio/trigger/stm32-timer-trigger.c | 49 ++++++++++++++---------
 1 file changed, 29 insertions(+), 20 deletions(-)

diff --git a/drivers/iio/trigger/stm32-timer-trigger.c b/drivers/iio/trigger/stm32-timer-trigger.c
index 0684329956d9..67528ec7d0a5 100644
--- a/drivers/iio/trigger/stm32-timer-trigger.c
+++ b/drivers/iio/trigger/stm32-timer-trigger.c
@@ -119,7 +119,7 @@ static int stm32_timer_start(struct stm32_timer_trigger *priv,
 			     unsigned int frequency)
 {
 	unsigned long long prd, div;
-	int prescaler = 0;
+	int prescaler = 0, ret;
 	u32 ccer;
 
 	/* Period and prescaler values depends of clock rate */
@@ -150,10 +150,12 @@ static int stm32_timer_start(struct stm32_timer_trigger *priv,
 	if (ccer & TIM_CCER_CCXE)
 		return -EBUSY;
 
-	mutex_lock(&priv->lock);
+	guard(mutex)(&priv->lock);
 	if (!priv->enabled) {
 		priv->enabled = true;
-		clk_enable(priv->clk);
+		ret = clk_enable(priv->clk);
+		if (ret)
+			return ret;
 	}
 
 	regmap_write(priv->regmap, TIM_PSC, prescaler);
@@ -173,7 +175,6 @@ static int stm32_timer_start(struct stm32_timer_trigger *priv,
 
 	/* Enable controller */
 	regmap_set_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN);
-	mutex_unlock(&priv->lock);
 
 	return 0;
 }
@@ -307,7 +308,7 @@ static ssize_t stm32_tt_store_master_mode(struct device *dev,
 	struct stm32_timer_trigger *priv = dev_get_drvdata(dev);
 	struct iio_trigger *trig = to_iio_trigger(dev);
 	u32 mask, shift, master_mode_max;
-	int i;
+	int i, ret;
 
 	if (stm32_timer_is_trgo2_name(trig->name)) {
 		mask = TIM_CR2_MMS2;
@@ -322,15 +323,16 @@ static ssize_t stm32_tt_store_master_mode(struct device *dev,
 	for (i = 0; i <= master_mode_max; i++) {
 		if (!strncmp(master_mode_table[i], buf,
 			     strlen(master_mode_table[i]))) {
-			mutex_lock(&priv->lock);
+			guard(mutex)(&priv->lock);
 			if (!priv->enabled) {
 				/* Clock should be enabled first */
 				priv->enabled = true;
-				clk_enable(priv->clk);
+				ret = clk_enable(priv->clk);
+				if (ret)
+					return ret;
 			}
 			regmap_update_bits(priv->regmap, TIM_CR2, mask,
 					   i << shift);
-			mutex_unlock(&priv->lock);
 			return len;
 		}
 	}
@@ -482,6 +484,7 @@ static int stm32_counter_write_raw(struct iio_dev *indio_dev,
 				   int val, int val2, long mask)
 {
 	struct stm32_timer_trigger *priv = iio_priv(indio_dev);
+	int ret;
 
 	switch (mask) {
 	case IIO_CHAN_INFO_RAW:
@@ -491,12 +494,14 @@ static int stm32_counter_write_raw(struct iio_dev *indio_dev,
 		/* fixed scale */
 		return -EINVAL;
 
-	case IIO_CHAN_INFO_ENABLE:
-		mutex_lock(&priv->lock);
+	case IIO_CHAN_INFO_ENABLE: {
+		guard(mutex)(&priv->lock);
 		if (val) {
 			if (!priv->enabled) {
 				priv->enabled = true;
-				clk_enable(priv->clk);
+				ret = clk_enable(priv->clk);
+				if (ret)
+					return ret;
 			}
 			regmap_set_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN);
 		} else {
@@ -506,11 +511,12 @@ static int stm32_counter_write_raw(struct iio_dev *indio_dev,
 				clk_disable(priv->clk);
 			}
 		}
-		mutex_unlock(&priv->lock);
+
 		return 0;
 	}
-
-	return -EINVAL;
+	default:
+		return -EINVAL;
+	}
 }
 
 static int stm32_counter_validate_trigger(struct iio_dev *indio_dev,
@@ -601,7 +607,7 @@ static int stm32_set_enable_mode(struct iio_dev *indio_dev,
 				 unsigned int mode)
 {
 	struct stm32_timer_trigger *priv = iio_priv(indio_dev);
-	int sms = stm32_enable_mode2sms(mode);
+	int sms = stm32_enable_mode2sms(mode), ret;
 
 	if (sms < 0)
 		return sms;
@@ -609,12 +615,15 @@ static int stm32_set_enable_mode(struct iio_dev *indio_dev,
 	 * Triggered mode sets CEN bit automatically by hardware. So, first
 	 * enable counter clock, so it can use it. Keeps it in sync with CEN.
 	 */
-	mutex_lock(&priv->lock);
-	if (sms == 6 && !priv->enabled) {
-		clk_enable(priv->clk);
-		priv->enabled = true;
+	scoped_guard(mutex, &priv->lock) {
+		if (sms == 6 && !priv->enabled) {
+			ret = clk_enable(priv->clk);
+			if (ret)
+				return ret;
+
+			priv->enabled = true;
+		}
 	}
-	mutex_unlock(&priv->lock);
 
 	regmap_update_bits(priv->regmap, TIM_SMCR, TIM_SMCR_SMS, sms);
 
-- 
2.25.1