On Fri, May 04, 2018 at 11:52:59PM +0200, Giulio Benetti wrote: > Hi Maxime! > > Il 04/05/2018 10:06, Maxime Ripard ha scritto: > > Hi, > > > > On Wed, May 02, 2018 at 06:41:34PM +0200, Giulio Benetti wrote: > > > > > You don't have to handcode the fragments anymore with the new syntax, > > > > > and U-Boot makes it really trivial to use if you use the FIT image > > > > > format to have multiple overlays bundled in the same image. You can > > > > > choose to apply them dynamically, for example based on an EEPROM or > > > > > some other metric to see which combination you have. > > > > > > > > Ah, this is interesting. I'm going to experiment with that. > > > > > > > > > > I'm struggling against this, I don't really know how to proceed, > > > except keeping monolithic dts files including other dtsi files. > > > > > > About dt-overlays I've tried to look around lot of time, > > > but the only thing I've found is this: > > > https://git.kernel.org/pub/scm/linux/kernel/git/geert/renesas-drivers.git/tree/arch/arm/boot/dts?h=topic/renesas-overlays > > > > > > where they use .dtso tagging them as "/plugin/;" > > > and compile all .dtso found in dts folder. > > > Then they obtain .dtbo files that should be the dt-overlays we have spoken > > > about right? > > > > Yes. You don't have to do that though, you can just rely on dtc to > > compile them, outside of the linux build system. > > > > > What I can't understand is if there's a real standard at this time to > > > follow, because on renesas-driver they use their way to handle all .dtso > > > files, but on mainline there seems to be nothing about that. > > > > I'm not sure what you mean here. It's just fragments of device tree, > > that have to be compiled using dtc, that's it. You can use the Linux > > build system infrastructure to do that, or you can build your own > > simpler one. That's really up to you. See for example > > https://github.com/NextThingCo/CHIP-dt-overlays/blob/master/Makefile > > > > (even though the overlays themselves use the legacy syntax and > > shouldn't really be used an examples) > > Everything works now! > Thank you very much! > I've setted up a Repo on Github to give an example on how make it work with > no pain: > https://github.com/micronovasrl/linova-dtoverlays > > At the moment it's a mess all around, but it's working and give an idea on > how to make it work. Though I'm going to clean it up well as a base for > linova dtoverlays. > > Ah, btw, can you confirm me that base dts file must be compiled outside > kernel with: > dtc -@ .... > Otherwise as in-tree dts with make dtbs "-@" argument is not passed. > Right? You should use DTC_FLAGS='-@' Maxime -- Maxime Ripard, Bootlin (formerly Free Electrons) Embedded Linux and Kernel engineering https://bootlin.com
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