Re: [PATCH] iio: temperature: tsys02d: Use guard(mutex) in tsys02d_write_raw()

[Jonathan Cameron <jic23@kernel.org>]

On Tue, 21 Apr 2026 12:40:01 -0300
lauraarakaki <lauraarakaki23@gmail.com> wrote:

> Replace the manual mutex_lock()/mutex_unlock() pair in
> tsys02d_write_raw() with guard(mutex)() from the scope-based
> cleanup helpers (include/linux/cleanup.h).
> 
Hi and welcome to IIO.

The wrap of this message is rather short. Normally we go
for 75 characters for a commit description.

> The previous code stored the return value of
> ms_sensors_write_resolution() in a local variable solely to
> bridge the gap between the manual mutex_unlock() call and the
> return statement. Using guard(mutex)() removes the need for
> both the intermediate variable and the explicit unlock call,
> since the mutex is released automatically when the function
> goes out of scope.
This paragraph is unnecessary detail.
> 
> No functional change intended.
> 
> Signed-off-by: lauraarakaki <lauraarakaki23@gmail.com>

> ---
>  drivers/iio/temperature/tsys02d.c | 11 ++++-------
>  1 file changed, 4 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/iio/temperature/tsys02d.c b/drivers/iio/temperature/tsys02d.c
> index 0cad27205667..55a55f2f4663 100644
> --- a/drivers/iio/temperature/tsys02d.c
> +++ b/drivers/iio/temperature/tsys02d.c
> @@ -10,6 +10,7 @@
>   *  http://www.meas-spec.com/downloads/Digital_Sensor_TSYS02D.pdf
>   */
>  
> +#include <linux/cleanup.h>
>  #include <linux/init.h>
>  #include <linux/device.h>
>  #include <linux/kernel.h>
> @@ -62,7 +63,7 @@ static int tsys02d_write_raw(struct iio_dev *indio_dev,
>  			     int val, int val2, long mask)
>  {
>  	struct ms_ht_dev *dev_data = iio_priv(indio_dev);
> -	int i, ret;
> +	int i;
>  
>  	switch (mask) {
>  	case IIO_CHAN_INFO_SAMP_FREQ:
> @@ -72,17 +73,13 @@ static int tsys02d_write_raw(struct iio_dev *indio_dev,
>  				break;
>  		if (i < 0)
>  			return -EINVAL;
> -		mutex_lock(&dev_data->lock);
> +		guard(mutex)(&dev_data->lock);
Unfortunately this broken because the non obvious definition of scope
in switch case statements.  You need to add {} in appropriate places.

See some similar threads from last few days.

>  		dev_data->res_index = i;
> -		ret = ms_sensors_write_resolution(dev_data, i);
> -		mutex_unlock(&dev_data->lock);
> -
> -		return ret;
> +		return ms_sensors_write_resolution(dev_data, i);
>  	default:
>  		return -EINVAL;
>  	}
>  }
> -
Unrelated change.  Always check for these and clean them up before posting.
>  static const struct iio_chan_spec tsys02d_channels[] = {
>  	{
>  		.type = IIO_TEMP,