Re: [PATCH v2 01/10] iio: light: opt3001: move device registration to end of probe()

[Joshua Crofts]

On Sat, 16 May 2026 at 13:56, Jonathan Cameron <jic23@xxxxxxxxxx> wrote:
>
> On Tue, 12 May 2026 12:57:21 +0200
> Joshua Crofts via B4 Relay <devnull+joshua.crofts1.gmail.com@xxxxxxxxxx> wrote:
>
> > From: Joshua Crofts <joshua.crofts1@xxxxxxxxx>
> >
> > Move devm_iio_device_register() to end of the opt3001_probe() function
> > to prevent a race condition where userspace could interact with the
> > device before the hardware IRQ was set up.
> >
> > Fixes: ac663db3678a ("iio: light: opt3001: enable operation w/o IRQ")
> > Reported-by: Jonathan Cameron <jic23@xxxxxxxxxx>
> > Reported-by: Sashiko <sashiko-bot@xxxxxxxxxx>
> > Closes: https://sashiko.dev/#/patchset/20260511-opt3001-cleanup-v1-0-f7879dc3455c%40gmail.com?part=7
> > Signed-off-by: Joshua Crofts <joshua.crofts1@xxxxxxxxx>
> > ---
> >  drivers/iio/light/opt3001.c | 10 ++++------
> >  1 file changed, 4 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/iio/light/opt3001.c b/drivers/iio/light/opt3001.c
> > index 53bc455b7bad142695d9fecc6cabb934fb3ace0c..3c79e0c4ca32fedf33e318d047d6ab3f62b6c03b 100644
> > --- a/drivers/iio/light/opt3001.c
> > +++ b/drivers/iio/light/opt3001.c
> > @@ -874,12 +874,6 @@ static int opt3001_probe(struct i2c_client *client)
> >       iio->modes = INDIO_DIRECT_MODE;
> >       iio->info = &opt3001_info;
> >
> > -     ret = devm_iio_device_register(dev, iio);
> > -     if (ret) {
> > -             dev_err(dev, "failed to register IIO device\n");
> > -             return ret;
> > -     }
> > -
> >       /* Make use of INT pin only if valid IRQ no. is given */
> >       if (irq > 0) {
> >               ret = request_threaded_irq(irq, NULL, opt3001_irq,
> > @@ -894,6 +888,10 @@ static int opt3001_probe(struct i2c_client *client)
> >               dev_dbg(opt->dev, "enabling interrupt-less operation\n");
> >       }
> >
> > +     ret = devm_iio_device_register(dev, iio);
> > +     if (ret)
> > +             return dev_err(dev, "failed to register IIO device\n");
>
> Sashiko correctly points out this won't build.  I guess you were aiming for
>         if (ret)
>                 return dev_err_probe(dev, ret, "failed to register IIO device\n");
>
> My eyes skipped right over that whilst reading :(

Yes, I've read the report and it should definitely be fixed, however
it is compilable
on my machine - what an oddity!

> The devres comment is also correct. So given this is a fix you can't do it
> like this.  You'd need to move to
>         ret = iio_device_register(iio);
> and explicit iio_device_unregister(iio) in remove.
>
> Then later put it back to devm when you convert the rest.

Good point, will push out in another series.

-- 
Kind regards

CJD