Re: [PATCH] iio: flow: slf3s: restart measurement if VDD disable fails

[Maxwell Doose]

On Wed, Aug 5, 2026 at 6:07 AM Linmao Li <lilinmao@xxxxxxxxxx> wrote:
>
> slf3s_suspend() stops continuous measurement before disabling VDD. If
> regulator_disable() fails while the supply remains enabled, the system
> sleep transition is aborted. Since the PM core does not call the
> corresponding resume callback for a device whose suspend callback failed,
> the sensor remains idle after the system returns to the running state and
> subsequent reads fail.
>
> Attempt to restart continuous measurement on this error path. Preserve the
> regulator error and warn if restarting the measurement also fails.
>
> Fixes: d240b0b8a1ce ("iio: flow: add Sensirion SLF3S liquid flow sensor driver")
> Signed-off-by: Linmao Li <lilinmao@xxxxxxxxxx>
> ---
>  drivers/iio/flow/slf3s.c | 12 +++++++++++-
>  1 file changed, 11 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/iio/flow/slf3s.c b/drivers/iio/flow/slf3s.c
> index dfa7c14090454..75ee82fbd3295 100644
> --- a/drivers/iio/flow/slf3s.c
> +++ b/drivers/iio/flow/slf3s.c
> @@ -462,6 +462,7 @@ static int slf3s_suspend(struct device *dev)
>  {
>         struct iio_dev *indio_dev = dev_get_drvdata(dev);
>         struct slf3s_data *sf = iio_priv(indio_dev);
> +       int restart_ret;
>         int ret;
>
>         guard(mutex)(&sf->lock);
> @@ -470,7 +471,16 @@ static int slf3s_suspend(struct device *dev)
>         if (ret)
>                 return ret;
>
> -       return regulator_disable(sf->vdd);
> +       ret = regulator_disable(sf->vdd);
> +       if (!ret)
> +               return 0;
> +
> +       restart_ret = slf3s_start_meas(sf, sf->medium);
> +       if (restart_ret)
> +               dev_warn(dev, "failed to restart measurement after suspend failure: %d\n",
> +                        restart_ret);
> +
> +       return ret;
>  }
>

In addition to David's question, why reenable vs keep it sleeping (and
why don't we dev_warn() after regulator disable failure)?

-- 
best regards,
max