[PATCH] of: Add more stubs for non-OF builds

[Grant Likely]

On Fri, 21 Jun 2013 19:56:29 +0100, Grant Likely <grant.likely at linaro.org> wrote:
> On Fri, Jun 21, 2013 at 7:35 PM, Alexander Shiyan <shc_work at mail.ru> wrote:
> >> >> On Fri, Jun 21, 2013 at 7:17 AM, Alexander Shiyan <shc_work at mail.ru> wrote:
> >> >> >> On Thu, Jun 20, 2013 at 5:26 PM, Grant Likely <grant.likely at linaro.org> wrote:
> >> >> >> > On Thu, 20 Jun 2013 16:49:54 -0700, Bryan Wu <cooloney at gmail.com> wrote:
> >> >> >> >> Hi Rob,
> >> >> >> >>
> >> >> >> >> Is this patch good for merging?
> >> >> >> >>
> >> >> >> >> In Alex's one patch to add device tree supporting for a leds driver,
> >> >> >> >> we got building errors due to miss definitions of some of_xxx api
> >> >> >> >> functions.
> >> >> >> >>
> >> >> >> >> It looks obviously to me that we need to fix this in device tree core
> >> >> >> >> instead put #ifdef CONFIG_OF everywhere.
> >> >> >> >
> >> >> >> > Actually, the reason those things aren't universally defined is to catch
> >> >> >> > exactly what it caught. The "leds-mc13783: Add devicetree support" patch
> >> >> >> > interleaves DT and non-DT parsing which isn't generally a good idea. The
> >> >> >> > DT parsing code should be shuffled off into a separate function and/or
> >> >> >> > contained with "if (IS_ENABLED(CONFIG_OF)) {}".
> >> >> >> >
> >> >> >>
> >> >> >> Agree, reasonable! I will remove this patch from my tree firstly.
> >> >> >>
> >> >> >> Alex, could you please update your patch with Grant's feedback?
> >> >> >
> >> >> > As far I understand you mean only the last part of patch. Where DT support
> >> >> > is introduced. Is not it?
> >> >> >
> >> >>
> >> >> Yes, exactly. I still keep those 2 non-DT related patches in my tree
> >> >> and just removed that DT supporting patch.
> >> >>
> >> >> Please update that patch and posted again to linux-leds and DT
> >> >> maintainers as well.
> >> >
> >> > I am really dont like any #ifdef in the source, but will do if this is only
> >> > one way to put this patch into the main tree.
> >>
> >> You don't need any #ifdefs. Put all the DT-related calls into a
> >> separate function specifically for decoding the DT information and
> >> wrap the contents with:
> >>
> >>     if (IS_ENABLED(CONFIG_OF)) { }
> >
> > This macro does not help for undefined reference, unfortunately.
> > So #ifdef and/or stubs for OF-functions is needed in this case anymore.
> >
> > if (IS_ENABLED(CONFIG_OF))
> >   some = of_get_next_child(foo, bar);
> > will produce an error at compile time if OF is not enabled,
> > because we have not empty function (if !OF) for this.
> 
> Check linux-next.

Oops, my apologies, of_get_next_child is still inside the CONFIG_OF
block. Arnd had written a patch to expose some of the OF prototypes, but
that was in of_platform.h, not of.h. Use a #ifdef block around the OF
parsing helper function for now until that is fixed in the header file.

g.