From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pantelis Antoniou Subject: Re: [PATCH v2 04/18] arm64: dts: m3ulcb-kf: initial device tree Date: Thu, 21 Sep 2017 12:40:55 +0300 Message-ID: <1505986855.23573.80.camel@hp800z> References: <1505398732-4614-1-git-send-email-vladimir.barinov@cogentembedded.com> <1505983900.23573.76.camel@hp800z> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Geert Uytterhoeven Cc: Vladimir Barinov , Simon Horman , Magnus Damm , Rob Herring , Mark Rutland , Catalin Marinas , Will Deacon , "devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Linux-Renesas List-Id: devicetree@vger.kernel.org Hi Geert, On Thu, 2017-09-21 at 11:10 +0200, Geert Uytterhoeven wrote: > Hi Pantelis, > > On Thu, Sep 21, 2017 at 10:51 AM, Pantelis Antoniou > wrote: > > On Wed, 2017-09-20 at 14:32 +0200, Geert Uytterhoeven wrote: > >> On Thu, Sep 14, 2017 at 4:18 PM, Vladimir Barinov > >> 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. > Yes, that would work on the DTS source level. Doesn't help at runtime. > That doesn't solve the DTB blob format issue yet, though. > Right. The tree and property deletion commands do not have a mapping to the DTB format. You could add special characters to a property name and have the overlay application code do something about it. For instance the original overlay submission did support property and node deletion by using '-property' & '-node'. Alas it was removed. > > 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. > Great. See you then. > Gr{oetje,eeting}s, > > Geert > Regards -- Pantelis > -- > Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert-Td1EMuHUCqxL1ZNQvxDV9g@public.gmane.org > > 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 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html