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[PATCH v4] iio: trigger: stm32-timer-trigger: Add check for clk_enable()

Jiasheng Jiang posted 1 patch 1 year, 2 months ago
There is a newer version of this series
drivers/iio/trigger/stm32-timer-trigger.c | 45 ++++++++++++++---------
1 file changed, 27 insertions(+), 18 deletions(-)
[PATCH v4] iio: trigger: stm32-timer-trigger: Add check for clk_enable()
Posted by Jiasheng Jiang 1 year, 2 months ago 
Add check for the return value of clk_enable() in order to catch the
potential exception.

Signed-off-by: Jiasheng Jiang <jiashengjiangcool@gmail.com>
---
Changelog:

v3 -> v4:

1. Place braces around the case body.

v2 -> v3:

1. Simplify code with cleanup helpers.

v1 -> v2:

1. Remove unsuitable dev_err_probe().
---
 drivers/iio/trigger/stm32-timer-trigger.c | 45 ++++++++++++++---------
 1 file changed, 27 insertions(+), 18 deletions(-)

diff --git a/drivers/iio/trigger/stm32-timer-trigger.c b/drivers/iio/trigger/stm32-timer-trigger.c
index 0684329956d9..d599d50fbb3b 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 {
@@ -506,9 +511,10 @@ static int stm32_counter_write_raw(struct iio_dev *indio_dev,
 				clk_disable(priv->clk);
 			}
 		}
-		mutex_unlock(&priv->lock);
+
 		return 0;
 	}
+	}
 
 	return -EINVAL;
 }
@@ -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
Re: [PATCH v4] iio: trigger: stm32-timer-trigger: Add check for clk_enable()
Posted by Jonathan Cameron 1 year, 2 months ago 
On Mon, 11 Nov 2024 22:23:10 +0000
Jiasheng Jiang <jiashengjiangcool@gmail.com> wrote:

> Add check for the return value of clk_enable() in order to catch the
> potential exception.
> 
> Signed-off-by: Jiasheng Jiang <jiashengjiangcool@gmail.com>
Hi Jiasheng,


Should definitely mention the changes to use guard() to simplify
the resulting code.

One minor comment on the code inline. Otherwise looks good to me.

Thanks,

Jonathan

> ---
> Changelog:
> 
> v3 -> v4:
> 
> 1. Place braces around the case body.
> 
> v2 -> v3:
> 
> 1. Simplify code with cleanup helpers.
> 
> v1 -> v2:
> 
> 1. Remove unsuitable dev_err_probe().

> @@ -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 {
> @@ -506,9 +511,10 @@ static int stm32_counter_write_raw(struct iio_dev *indio_dev,
>  				clk_disable(priv->clk);
>  			}
>  		}
> -		mutex_unlock(&priv->lock);
> +
>  		return 0;
>  	}
Add a default for reasons David mentioned and it also makes it visually clear
that we expect to get in here for other cases but they are all errors.
	default:
		return -EINVAL;
> +	}
>  
And drop this return as unreachable.

>  	return -EINVAL;
>  }
Re: [PATCH v4] iio: trigger: stm32-timer-trigger: Add check for clk_enable()
Posted by Jiasheng Jiang 1 year, 2 months ago 
Hi Jonathan,

On Sat, Nov 23, 2024 at 10:08 AM Jonathan Cameron <jic23@kernel.org> wrote:
>
> On Mon, 11 Nov 2024 22:23:10 +0000
> Jiasheng Jiang <jiashengjiangcool@gmail.com> wrote:
>
> > Add check for the return value of clk_enable() in order to catch the
> > potential exception.
> >
> > Signed-off-by: Jiasheng Jiang <jiashengjiangcool@gmail.com>
> Hi Jiasheng,
>
>
> Should definitely mention the changes to use guard() to simplify
> the resulting code.

Thanks, I have revised the "v2 -> v3" in the Changelog to clarify the changes.

> One minor comment on the code inline. Otherwise looks good to me.
>
> Thanks,
>
> Jonathan
>
> > ---
> > Changelog:
> >
> > v3 -> v4:
> >
> > 1. Place braces around the case body.
> >
> > v2 -> v3:
> >
> > 1. Simplify code with cleanup helpers.
> >
> > v1 -> v2:
> >
> > 1. Remove unsuitable dev_err_probe().
>
> > @@ -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 {
> > @@ -506,9 +511,10 @@ static int stm32_counter_write_raw(struct iio_dev *indio_dev,
> >                               clk_disable(priv->clk);
> >                       }
> >               }
> > -             mutex_unlock(&priv->lock);
> > +
> >               return 0;
> >       }
> Add a default for reasons David mentioned and it also makes it visually clear
> that we expect to get in here for other cases but they are all errors.
>         default:
>                 return -EINVAL;
> > +     }
> >
> And drop this return as unreachable.
>
> >       return -EINVAL;
> >  }

Thanks, I have submitted v5 to include a default and remove the return.

-Jiasheng
Re: [PATCH v4] iio: trigger: stm32-timer-trigger: Add check for clk_enable()
Posted by David Lechner 1 year, 2 months ago 
On 11/11/24 4:23 PM, Jiasheng Jiang wrote:
> Add check for the return value of clk_enable() in order to catch the
> potential exception.
> 
> Signed-off-by: Jiasheng Jiang <jiashengjiangcool@gmail.com>
> ---
Reviewed-by: David Lechner <dlechner@baylibre.com>

Patchew 2.1-devel-b67e4c2

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