Javier, On Sun, Sep 7, 2014 at 11:09 PM, Javier Martinez Canillas <javier.martinez@xxxxxxxxxxxxxxx> wrote: > Hello Doug, > > On 09/08/2014 06:36 AM, Doug Anderson wrote: >> >> One (ugly?) solution would be to add a feature to your bootloader to >> modify the device tree to mark regulators as "always-on". Since the >> booloader gets to touch the device tree and the bootloader is involved >> in communicating into about SimpleFB, it kinda makes sense. >> > > I can't say I like to mark the regulators as always-on on the DT and that's > why I copied the patch in the response instead of posting it as a proper patch > but I think relying in the bootloaders to modify the DT is not better. > > IMHO U-boot should only modify the strictly necessary like the /chosen branch > even though lately I've seen some attempts in the OMAP community to (ab)use > U-Boot's fdt command to mangle the DT before passing to the kernel in order to > support different Beagle Bone Black capes. So "simple-framebuffer" is added to the device tree here: https://chromium-review.googlesource.com/#/c/49358/2/board/samsung/smdk5250/smdk5250.c That's one of the two patches to build your own U-Boot for enabling simplefb. You'll notice that's not a super official thing. It's a "DO NOT SUBMIT" patch sitting in a gerrit code review server, so I wouldn't exactly call it a stable ABI that we can't break. It's not something shipping in real products and it's not even landed in a git tree (I suppose maybe someone somewhere landed it, but...). To me, that means that if someone is using that patch and it works for them, then that's great! If it stops working (possibly because it was making assumptions about the state of the kernel) then it should be fixed up. In this case, that patch really should be adding references to regulators (and possibly clocks) that are needed. Given that this patch is already reaching into the device tree to add the "simple-framebuffer" node, it doesn't seem unreasonable to say that it should be grabbing the proper references (or mark regulators as always-on). ...as always, though, remember that my opinion doesn't count for much. I also sympathize with the problems people are running into. :( -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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