And adding a non-blank subject so people won't ignore the thread. -Frank On 5/18/2016 11:02 AM, Rob Herring wrote: > +devicetree-spec which is the right list. > > On Wed, May 18, 2016 at 11:26 AM, Warner Losh <imp@xxxxxxxxxx> wrote: >> Greetings, >> >> I was looking at the draft link posted here >> https://github.com/devicetree-org/devicetree-specification-released/blob/master/prerelease/devicetree-specification-v0.1-pre1-20160429.pdf >> a while ago. I hope this is the right place to ask about it. >> >> It raised a bit of a question. There's nothing in it talking about the >> current >> practice of using CPP to pre-process the .dts/.dtsi files before passing >> them >> into dtc to compile them into dtb. > > Can't say I'm really a fan of it. > >> Normally, I see such things outside the scope of standardization. However, >> many of the .dts files that are in the wild today use a number of #define >> constants to make things more readable (having GPIO_ACTIVE_HIGH >> instead of '0' makes the .dts files easier to read). However, there's a >> small >> issue that I've had. The files that contain those definitions are currently >> in the Linux kernel and have a wide variety of licenses (including none >> at all). > > Yes, this is a problem. In lieu of any explicit license, I'd say the > license defaults to GPL. There is also the same issue with the > Documentation as we plan to move some of the common bindings such as > clocks, gpio, etc. into the spec which is Apache licensed. > > In both cases, we're going to need to get permission of the authors to > re-license. For the headers, these should be patches to the kernel. > For the docs, we just need to record the permission when committing > the addition to the spec. Neither should be too hard as they should > not be changing much and we have complete history in git. > >> So before even getting to the notion of licenses and such (which past >> expereince suggests may be the worst place to start a discussion), I'm >> wondering where that will be defined, and if these #defines will become >> part of the standard for each of the bindings that are defined. > > Perhaps. We need to at least define the standard flag values if not > the symbolic name. I don't think it makes sense to both document and > maintain headers of the defines. We should ideally just have 1 source > for all and generate what we need from it. There's been some related > discussion around having machine parseable bindings as both the > documentation source and binding validation source, but nothing > concrete. > >> I'm also wondering where the larger issue of using cpp to process the dts >> files will be discussed, since FreeBSD's BSDL dtc suffers interoperability >> due to this issue. Having the formal spec will also be helpful for its care and >> feeding since many fine points have had to be decided based on .dts >> files in the wild rather than a clear spec. >> >> Thanks again for spear-heading the effort to get a new version out now >> that ePAPR has fallen on hard times. >> >> Warner >> >> P.S. I'm mostly a FreeBSD guy, but just spent some time digging into this >> issue for another of the BSDs that's considering adopting DTS files. > > We certainly need and want the BSD folks involved in the spec. > > Rob > -- > To unsubscribe from this list: send the line "unsubscribe devicetree" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe devicetree-spec" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
