Re: [PATCH] iio: chemical: scd30: Prevent potential divide-by-zero error

[Maxwell Doose]

On Sat, May 9, 2026 at 4:25 PM David Lechner <dlechner@xxxxxxxxxxxx> wrote:
>
> On 5/9/26 4:19 PM, Maxwell Doose wrote:
> > In scd30_read_raw, the current value of tmp in the
> > IIO_CHAN_INFO_SAMP_FREQ case is unchecked. Add checking to see if the
> > value we got was 0 to prevent a divide-by-zero error.
> >
> > Fixes: 64b3d8b1b0f5 ("iio: chemical: scd30: add core driver")
> > Signed-off-by: Maxwell Doose <m32285159@xxxxxxxxx>
> > ---
> >  drivers/iio/chemical/scd30_core.c | 7 +++++++
> >  1 file changed, 7 insertions(+)
> >
> > diff --git a/drivers/iio/chemical/scd30_core.c b/drivers/iio/chemical/scd30_core.c
> > index be8c055be184..3e2bb6f4e42c 100644
> > --- a/drivers/iio/chemical/scd30_core.c
> > +++ b/drivers/iio/chemical/scd30_core.c
> > @@ -237,6 +237,13 @@ static int scd30_read_raw(struct iio_dev *indio_dev, struct iio_chan_spec const
> >               if (ret)
> >                       return ret;
> >
> > +             /* Likely only taken if something really strange happens */
>
> Instead of saying "strange" I would mention a possible hardware failure
> to justify the EIO return. I'm assuming this is reading the value over
> SPI or I2C?
>

Yes, we're reading over either SPI or I2C, the sensor supports both.
Hardware failure is going to be the most likely cause of this path
being taken, but I could also see some sort of noise on the bus being
the cause. Perhaps we change it to:

/* Likely taken if hardware is failing or noise on bus */

best regards,
max