Re: [PATCH v3] gpiolib: match secondary fwnode too in gpio_device_find_by_fwnode()

[Bartosz Golaszewski]

On Wed, Feb 25, 2026 at 1:44 PM Rafael J. Wysocki <rafael@xxxxxxxxxx> wrote:
> >
> > The second check is redundant because fwnode cannot be an error
> > pointer (it has been checked against that already above) and so if
> > node->secondary == fwnode, then node->secondary is not an error
> > pointer.
> >
> > I'm not sure if fwnode can be NULL here, but if it can, it should be
> > checked against NULL.  Alternatively, node->secondary can be checked
> > against NULL and compared to fwnode.
> >
> > So, if fwnode != NULL cannot be guaranteed,
> >
> >         return fwnode && node && node->secondary == fwnode;
> >
> > or
> >
> >         return node && node->secondary && node->secondary == fwnode;
> >
> > The overhead of the former may be a bit lower because it avoids
> > dereferencing node when fwnode is NULL, but the compiler should be
> > able to optimize this anyway.
>
> Or even the device_match_fwnode() check can be folded into the last line:
>
> static int gpio_chip_match_by_fwnode(struct gpio_chip *gc, const void *fwnode)
>  {
> -       return device_match_fwnode(&gc->gpiodev->dev, fwnode);
> +       struct device *dev = &gc->gpiodev->dev;
> +       struct fwnode_handle *node = dev_fwnode(dev);
> +
> +       if (IS_ERR_OR_NULL(fwnode))
> +               return 0;
> +
> +       return node == fwnode || (node && node->secondary == fwnode);
>  }

device_match_fwnode() already contains the NULL check for fwnode. I'm
sending a v4 with the IS_ERR() check for secondary dropped I hope this
is the final one.

Bart