On Tue, Feb 11, 2014 at 03:55:35PM +0100, Laurent Pinchart wrote:
> Hi Josh,
>
> On Tuesday 11 February 2014 08:41:08 Josh Cartwright wrote:
> > On Tue, Feb 11, 2014 at 01:36:51PM +0100, Laurent Pinchart wrote:
> > > when CONFIG_OF is disabled of_match_node is defined as a macro that
> > > evaluates to NULL. This breaks compilation of drivers that dereference
> > > the function's return value directly. Fix it by turning the macro into a
> > > static inline function that returns NULL.
> >
> > Just this past week I did the same thing, but noticed that it breaks the
> > following usecase:
> >
> > #ifdef CONFIG_OF
> > static const struct of_device_id foobar_matches[] = {
> > { .compatible = "foobar,whatsit", },
> > { },
> > };
> > #endif
> >
> > static int probeme(struct platform_device *pdev)
> > {
> > struct of_device_id *id;
> >
> > id = of_match_node(foobar_matches, pdev->dev.of_node);
> > if (id) {
> > /* ... */
> > }
> > return 0;
> > }
> >
> > When !CONFIG_OF and with your change, this will fail to build due to
> > foobar_matches being undefined.
>
> Good point. What would you think about
>
> #define of_match_node(_matches, _node) ((const struct of_device_id *)NULL)
I've just sent out a patchset that cleans up at least a couple of users
that directly do of_match_node(matches, np)->data using
of_find_matching_node_and_match. Not sure if that will fix the usage
you have in mind, though.
I am a bit weary about having an of_match_node() user that both directly
dereferences the result (i.e. of_match_node(matches, np)->data) _and_
builds when !CONFIG_OF; most likely due to a traumatic childhood event
where demons flew out my nose.
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