Hi Pantelis, On Thu, Sep 21, 2017 at 10:51 AM, Pantelis Antoniou <pantelis.antoniou@xxxxxxxxxxxx> wrote: > On Wed, 2017-09-20 at 14:32 +0200, Geert Uytterhoeven wrote: >> On Thu, Sep 14, 2017 at 4:18 PM, Vladimir Barinov >> <vladimir.barinov@xxxxxxxxxxxxxxxxxx> wrote: >> > +#include "ulcb-kf.dtsi" >> >> As the Kingfisher is actually an expansion board for H3ULCB (with R-Car H3 >> ES1.1 and ES2.0) and M3ULCB (with R-Car M3-W), turning ulcb-kf.dtsi into a >> DT overlay would make sense. >> That would also solve the issue of the 3 extra DTSes needed for all possible >> combinations of ULCB and Kingfisher (r8a7795-es1-h3ulcb-kf.dts, >> r8a7795-h3ulcb-kf.dts, r8a7796-h3ulcb-kf.dts (perhaps more to follow?)). >> >> But that's too premature, without upstream support for the easy loading of >> DT overlays. >> > > Sigh, yes. > >> > +/ { >> > + model = "Renesas M3ULCB Kingfisher board based on r8a7796"; >> > + compatible = "shimafuji,kingfisher", "renesas,m3ulcb", >> > + "renesas,r8a7796"; >> > +}; >> >> And how to support from an overlay the addition of "shimafuji,kingfisher" to >> (not replacement of!) the main compatible value? > > You can hack something in DT but it will be gross indeed. > > Ideally you'd want a += operator, but it's going to take a lot of > changes starting from DTB blob format. > > In yaml we could easily do this with an append tag type > > compatible: [ "renesas,m3ulcb", "renesas,r8a7796" ] > > compatible: !append "shimafuji,kingfisher" As we already have /delete-property/, we could add /append-property/ and /prepend-property/? Would be useful for a .dts including and enhancing an .dtsi, too. That doesn't solve the DTB blob format issue yet, though. > Are you going to be at ELCE? I have a bunch of thing to ask you about > your DT usage patterns. Yes, and registered for the Device Tree Workshop. Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds