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

[Grant Likely]

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.

g.