Re: [PATCH v2 2/2] gpiolib: check the 'ngpios' property in core gpiolib code

[Bartosz Golaszewski <brgl@xxxxxxxx>]

On Thu, Nov 18, 2021 at 4:46 PM Andy Shevchenko
<andriy.shevchenko@xxxxxxxxxxxxxxx> wrote:
>
> On Thu, Nov 18, 2021 at 02:23:17PM +0100, Bartosz Golaszewski wrote:
> > Several drivers read the 'ngpios' device property on their own, but
> > since it's defined as a standard GPIO property in the device tree bindings
> > anyway, it's a good candidate for generalization. If the driver didn't
> > set its gc->ngpio, try to read the 'ngpios' property from the GPIO
> > device's firmware node before bailing out.
>
> Thanks for update, my comment below.
>
> ...
>
> >       if (gc->ngpio == 0) {
> > -             chip_err(gc, "tried to insert a GPIO chip with zero lines\n");
> > -             ret = -EINVAL;
> > -             goto err_free_descs;
> > +             ret = device_property_read_u32(&gdev->dev, "ngpios", &ngpios);
> > +             if (ret) {
> > +                     chip_err(gc, "tried to insert a GPIO chip with zero lines\n");
>
> > +                     ret = -EINVAL;
>
> Sorry, forgot to ask, why this is needed?
>

What do you mean? 0 lines doesn't sound like a valid value so -EINVAL
is in order.

Bart