On 08/09/2011 09:13 PM, Scott Wood wrote: > On 08/09/2011 01:45 PM, Robin Holt wrote: >> On Tue, Aug 09, 2011 at 01:17:47PM -0500, Scott Wood wrote: >>> On 08/09/2011 09:43 AM, Robin Holt wrote: >>>> In working with the socketcan developers, we have come to the conclusion >>>> the fsl-flexcan device tree bindings need to be cleaned up. >>>> The driver does not depend upon any properties other than the required >>>> properties >>>> so we are removing the file. >>> >>> That is not the criterion for whether something should be expresed in >>> the device tree. It's a description of the hardware, not a Linux driver >>> configuration file. If there are integration parameters that can not be >>> inferred from "this is FSL flexcan v1.0", they should be expressed in >>> the node. >> >> There are no properties other than the required properties. The others >> were wrongly introduced and are not needed by the driver. > > Not needed by this driver, or will never be needed by any reasonable > driver (or is not a good description of the hardware)? > > The device tree is not an internal Linux implementation detail. It is > shared by other OSes, firmwares, hypervisors, etc. Bindings should be > created with care, and kept stable unless there's a good reason to break > compatibility. > > devicetree-disc...@lists.ozlabs.org should be CCed on device tree > discussions.
Yes. The doc for the bindings we speak about http://lxr.linux.no/#linux+v3.0.1/Documentation/devicetree/bindings/net/can/fsl-flexcan.txt sneaked into the kernel without been presented on any mailing list and without the corresponding driver patch. >> When we >> removed the other properties and the wrong documentation of the mscan >> oscillator source in the fsl-flexcan.txt file, we were left with an >> Example: section and a one-line statement "The only properties supported >> are the required properties." That seemed like the fsl-flexcan.txt >> file was then pointless. > > There is the compatible string, and you could mention that there is a > single reg resource and a single interrupt. > >>> Removing the binding altogether seems extreme as well -- we should have >>> bindings for all devices, even if there are no special properties. >> >> Ok. I can do that too. Who is the definitive source for that answer? > > For policy questions on device tree bindings? Grant Likely is the > maintainer for device tree stuff. > > A lot of the simpler bindings have been left undocumented so far, IMHO > it should be a goal to document them all. There are some existing ones > that are documented despite not having special properties, e.g. > Documentation/devicetree/bindings/serio/altera_ps2.txt, > Documentation/devicetree/bindings/arm/sirf.txt, > Documentation/devicetree/bindings/powerpc/nintendo/wii.txt, etc. > >> I assume we are talking about the fsl-flexcan.txt file when we say >> binding. Is that correct? > > Yes, although devicetree.org is another possibility. > >>>> Additionally, the p1010*dts files are not >>>> following the standard for node naming in that they have a trailing -v1.0. >>> >>> What "standard for node naming"? There's nothing wrong with putting a >> >> For the answer to that, you will need to ask Wolfgang Grandegger. I was >> working from his feedback. Looking at the plethora of other node names, >> the vast majority do not have any -v#.#, and the ones that do also tend >> to have multiple versions. Based upon that, I suspect he is correct, >> but I do not know where the documentation is or if it even exists. > > There's a lot of crap in old bindings, plus it's not appropriate for all > circumstances (specifying bindings should be done a little more > carefully than "what do most other bindings do?"). It's something we've > been doing lately for blocks that have a version number, but it's not > dynamically readable. > > Looking in the FlexCAN chapter of the p1010 manual, I don't see any > reference to a block version, and I do see references to "previous > FlexCAN versions". So I suggest "fsl,p1010-flexcan". OK, just "fsl,p1010-flexcan" or "fsl,p1010-flexcan", "fsl,flexcan" Note that the Flexcan is used on Freescale ARM cores as well (and device tree for ARM will show up soon). Wolfgang. _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
