Re: [PATCH] iio: proximity: rfd77402: Fix completion race condition in IRQ mode

[Shrikant]

On Wed, Mar 4, 2026 at 7:44 PM Felix Gu <ustc.gu@xxxxxxxxx> wrote:
>
> In IRQ mode, the completion was being reinitialized after the
> measurement command had already been sent to the hardware. This
> created a race condition where the IRQ handler could call complete()
> before reinit_completion() was executed. Consequently,
> wait_for_completion_timeout() would fail to see the signal and wait
> until it timed out.
>
> Move reinit_completion() to occur before the measurement command is
> triggered to ensure the synchronization primitive is ready to
> capture the interrupt.
>
> Fixes: dc81be96a73a ("iio: proximity: rfd77402: Add interrupt handling support")
> Signed-off-by: Felix Gu <ustc.gu@xxxxxxxxx>
> ---
>  drivers/iio/proximity/rfd77402.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/iio/proximity/rfd77402.c b/drivers/iio/proximity/rfd77402.c
> index 6afdbfca3e5a..81b8daf17a54 100644
> --- a/drivers/iio/proximity/rfd77402.c
> +++ b/drivers/iio/proximity/rfd77402.c
> @@ -173,10 +173,8 @@ static int rfd77402_wait_for_result(struct rfd77402_data *data)
>         struct i2c_client *client = data->client;
>         int val, ret;
>
> -       if (data->irq_en) {
> -               reinit_completion(&data->completion);
> +       if (data->irq_en)
>                 return rfd77402_wait_for_irq(data);
> -       }
>
>         /*
>          * As per RFD77402 datasheet section '3.1.1 Single Measure', the
> @@ -204,6 +202,9 @@ static int rfd77402_measure(struct rfd77402_data *data)
>         if (ret < 0)
>                 return ret;
>
> +       if (data->irq_en)
> +               reinit_completion(&data->completion);
> +
Looks good to me.
Reviewed-by: Shrikant Raskar <raskar.shree97@xxxxxxxxx>

Regards,
Shrikant