Re: [PATCH] iio: chemical: sps30: Replace manual locking with RAII locking

[Joshua Crofts]

On Sat, 9 May 2026 at 14:53, Maxwell Doose <m32285159@xxxxxxxxx> wrote:
>
> Replace manual mutex_lock() and mutex_unlock() calls with the much newer
> guard(mutex)() and scoped_guard() macros to enable RAII patterns,
> modernize the driver, and to increase readability.
>
> Signed-off-by: Maxwell Doose <m32285159@xxxxxxxxx>
> ---
>  drivers/iio/chemical/sps30.c | 60 +++++++++++++++++-------------------
>  1 file changed, 29 insertions(+), 31 deletions(-)
>
> diff --git a/drivers/iio/chemical/sps30.c b/drivers/iio/chemical/sps30.c
> index a934bf0298dd..186dec4cfd78 100644
> --- a/drivers/iio/chemical/sps30.c
> +++ b/drivers/iio/chemical/sps30.c
> @@ -5,6 +5,7 @@
>   * Copyright (c) Tomasz Duszynski <tduszyns@xxxxxxxxx>
>   */
>
> +#include <linux/cleanup.h>
>  #include <linux/crc8.h>
>  #include <linux/delay.h>
>  #include <linux/i2c.h>
> @@ -111,9 +112,9 @@ static irqreturn_t sps30_trigger_handler(int irq, void *p)
>                 aligned_s64 ts;
>         } scan;
>
> -       mutex_lock(&state->lock);
> -       ret = sps30_do_meas(state, scan.data, ARRAY_SIZE(scan.data));
> -       mutex_unlock(&state->lock);
> +       scoped_guard(mutex, &state->lock)
> +               ret = sps30_do_meas(state, scan.data, ARRAY_SIZE(scan.data));
> +
>         if (ret)
>                 goto err;
>
> @@ -136,23 +137,23 @@ static int sps30_read_raw(struct iio_dev *indio_dev,
>         case IIO_CHAN_INFO_PROCESSED:
>                 switch (chan->type) {
>                 case IIO_MASSCONCENTRATION:
> -                       mutex_lock(&state->lock);
> -                       /* read up to the number of bytes actually needed */
> -                       switch (chan->channel2) {
> -                       case IIO_MOD_PM1:
> -                               ret = sps30_do_meas(state, data, 1);
> -                               break;
> -                       case IIO_MOD_PM2P5:
> -                               ret = sps30_do_meas(state, data, 2);
> -                               break;
> -                       case IIO_MOD_PM4:
> -                               ret = sps30_do_meas(state, data, 3);
> -                               break;
> -                       case IIO_MOD_PM10:
> -                               ret = sps30_do_meas(state, data, 4);
> -                               break;
> +                       scoped_guard(mutex, &state->lock) {
> +                               /* read up to the number of bytes actually needed */
> +                               switch (chan->channel2) {
> +                               case IIO_MOD_PM1:
> +                                       ret = sps30_do_meas(state, data, 1);
> +                                       break;
> +                               case IIO_MOD_PM2P5:
> +                                       ret = sps30_do_meas(state, data, 2);
> +                                       break;
> +                               case IIO_MOD_PM4:
> +                                       ret = sps30_do_meas(state, data, 3);
> +                                       break;
> +                               case IIO_MOD_PM10:
> +                                       ret = sps30_do_meas(state, data, 4);
> +                                       break;
> +                               }
>                         }
> -                       mutex_unlock(&state->lock);
>                         if (ret)
>                                 return ret;
>
> @@ -197,9 +198,9 @@ static ssize_t start_cleaning_store(struct device *dev,
>         if (kstrtoint(buf, 0, &val) || val != 1)
>                 return -EINVAL;
>
> -       mutex_lock(&state->lock);
> -       ret = state->ops->clean_fan(state);
> -       mutex_unlock(&state->lock);
> +       scoped_guard(mutex, &state->lock)
> +               ret = state->ops->clean_fan(state);
> +
>         if (ret)
>                 return ret;
>
> @@ -215,9 +216,9 @@ static ssize_t cleaning_period_show(struct device *dev,
>         __be32 val;
>         int ret;
>
> -       mutex_lock(&state->lock);
> -       ret = state->ops->read_cleaning_period(state, &val);
> -       mutex_unlock(&state->lock);
> +       scoped_guard(mutex, &state->lock)
> +               ret = state->ops->read_cleaning_period(state, &val);
> +
>         if (ret)
>                 return ret;
>
> @@ -238,12 +239,11 @@ static ssize_t cleaning_period_store(struct device *dev, struct device_attribute
>             (val > SPS30_AUTO_CLEANING_PERIOD_MAX))
>                 return -EINVAL;
>
> -       mutex_lock(&state->lock);
> +       guard(mutex)(&state->lock);
> +
>         ret = state->ops->write_cleaning_period(state, cpu_to_be32(val));
> -       if (ret) {
> -               mutex_unlock(&state->lock);
> +       if (ret)
>                 return ret;
> -       }
>
>         msleep(20);
>
> @@ -256,8 +256,6 @@ static ssize_t cleaning_period_store(struct device *dev, struct device_attribute
>                 dev_warn(dev,
>                          "period changed but reads will return the old value\n");
>
> -       mutex_unlock(&state->lock);
> -
>         return len;
>  }
>
> --
> 2.54.0
>
>

LGTM.

Reviewed-by: Joshua Crofts <joshua.crofts1@xxxxxxxxx>

-- 
Kind regards

CJD