From mboxrd@z Thu Jan 1 00:00:00 1970 From: Grant Likely Subject: Re: [PATCH 0/3] capebus moving omap_devices to mach-omap2 Date: Mon, 5 Nov 2012 20:14:15 +0000 Message-ID: References: <50924DA3.1060901@ti.com> <20121101110418.GF410@arwen.pp.htv.fi> <3AF5A6FC-61D9-40CA-85B3-81C2C788CB76@antoniou-consulting.com> <20121101124025.GA12489@arwen.pp.htv.fi> <20121101131609.GC12489@arwen.pp.htv.fi> <20121101135148.382aec00@pyramind.ukuu.org.uk> <9F25E89E-9194-4725-8A8C-053DCBADA1DB@antoniou-consulting.com> <20121101220518.GE14982@arwen.pp.htv.fi> <20121102112104.4657fb7b@pyramind.ukuu.org.uk> <0EC43413-1DD7-4E2A-879B-0B5B926FFDFE@antoniou-consulting.com> <18667A4E-5513-4D74-922F-30D091609F16@antoniou-consulting.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Return-path: In-Reply-To: <18667A4E-5513-4D74-922F-30D091609F16@antoniou-consulting.com> Sender: linux-kernel-owner@vger.kernel.org To: Pantelis Antoniou Cc: Alan Cox , Russ Dill , Felipe Balbi , Benoit Cousson , Tony Lindgren , linux-kernel , Koen Kooi , Matt Porter , linux-omap@vger.kernel.org, Kevin Hilman , Paul Walmsley , devicetree-discuss@lists.ozlabs.org, Rob Herring List-Id: devicetree@vger.kernel.org On Mon, Nov 5, 2012 at 7:54 PM, Pantelis Antoniou wrote: >> This handles many of the use cases, but it assumes that an overlay is >> board specific. If it ever is required to support multiple base boards >> with a single overlay file then there is a problem. The .dtb overlays >> generated in this manor cannot handle different phandles or nodes that >> are in a different place. On the other hand, the overlay source files >> should have no problem being compiled for multiple targets, so maybe >> it isn't an issue. Plus if dtc is installed on the target, then the >> live tree from /proc can be used as the reference when compiling the >> overlay. > > My worry is that this format is dependent on linking against the board > DTS file. One of the ideas thrown around here was that it might make > sense to store the DTB fragment in the EEPROM of the device. Right, that wouldn't work well if the base DT changed, or if a BeagleBone2 is released that has the same header configuration, but different backing devices. It would be nice to have a solution for that. > In that case you have a OS independent hardware description, which can > be even used even by the bootloader to access devices it knows not about > at compile time. > > Other than that, I have no other objections. I'm open to suggestions if anyone has any. I have not objections to a fixup approach, but I'm not comfortable with anything that is fragile to modifications to the fragment. g.