[Buildroot] [PATCH] Add out-of-source U-Boot device tree support

[Arnout Vandecappelle <arnout@mind.be>]

On 28-03-17 21:53, Thomas Petazzoni wrote:
> Hello,
> 
> On Tue, 28 Mar 2017 11:01:46 +0200, Arnout Vandecappelle wrote:
> 
>>> Have reconsidered this suggestion. I think that perhaps it would be best
>>> not to make the U-boot option dependent on the Linux option. As Linux
>>> and U-Boot use two different device tree sources, there may be occasions
>>> when custom DTS configuration must be made to one or the other rather
>>> than both. This is the case with my boards, which have device tree
>>> support in Linux, but not in U-Boot.  
>>
>>  Certainly, but I only suggested to *default* to the same DTS. It is also
>> possible that the kernel isn't built at all by Buildroot, or that it uses an
>> in-tree DTS, or that it is built without DTS because the DTB is provided by
>> U-Boot. All of these cases are covered by the "if
>> BR2_LINUX_KERNEL_USE_CUSTOM_DTS" part. And even if the both kernel and U-Boot
>> use a DTS, it is possible to change the default.
> 
> I am not entirely convinced that this:
> 
>   default BR2_LINUX_KERNEL_CUSTOM_DTS_PATH if BR2_LINUX_KERNEL_USE_CUSTOM_DTS
> 
> is really a good idea. IMO, it tries to be too "clever". I'd really
> prefer to keep the U-Boot and Linux configurations independent from
> each other.

 Yeah, thinking a bit more about it: if you use the same DT in U-Boot as in the
kernel, then you probably let U-Boot pass it to the kernel so you don't need it
at kernel build time...

 So forget I suggested this :-)

 Regards,
 Arnout

-- 
Arnout Vandecappelle                          arnout at mind be
Senior Embedded Software Architect            +32-16-286500
Essensium/Mind                                http://www.mind.be
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