Re: [linux-devel] [PATCH v2 1/1] arm64: Add DTS support for FSL's LS1012A SoC

[Shawn Guo <shawnguo@kernel.org>]

On Fri, Sep 30, 2016 at 11:38:29AM +0000, Bhaskar U wrote:
> 
> 
> >-----Original Message-----
> >From: Scott Wood
> >Sent: Tuesday, September 06, 2016 10:36 PM
> >To: Shawn Guo <shawnguo@kernel.org>; Stuart Yoder <stuart.yoder@nxp.com>;
> >Rob Herring <robh+dt@kernel.org>; Mark Rutland <mark.rutland@arm.com>
> >Cc: devicetree@vger.kernel.org; Bhaskar U <bhaskar.upadhaya@nxp.com>; Scott
> >Wood <oss@buserror.net>; Prabhakar Kushwaha
> ><prabhakar.kushwaha@nxp.com>; linux-devel@gforge.freescale.net; Pratiyush
> >Srivastava <pratiyush.srivastava@nxp.com>; linux-arm-
> >kernel@lists.infradead.org
> >Subject: Re: [linux-devel] [PATCH v2 1/1] arm64: Add DTS support for FSL's
> >LS1012A SoC
> >
> >On 09/04/2016 08:47 PM, Shawn Guo wrote:
> >> On Tue, Aug 30, 2016 at 02:07:17PM +0000, Stuart Yoder wrote:
> >>>> On Mon, Aug 29, 2016 at 12:51:01PM -0500, Scott Wood wrote:
> >>>>> On Mon, 2016-08-29 at 17:52 +0800, Shawn Guo wrote:
> >>>>>> On Fri, Aug 26, 2016 at 03:57:21PM +0530, Bhaskar Upadhaya wrote:
> >>>>>>>
> >>>>>>> +		clockgen: clocking@1ee1000 {
> >>>>>>> +			compatible = "fsl,ls1012a-clockgen";
> >>>>>> The compatible cannot be found in binding docs.
> >>>>>
> >>>>> From Documentation/devicetree/bindings/clock/qoriq-clock.txt:
> >>>>>
> >>>>> - compatible: Should contain a chip-specific clock block compatible
> >>>>>         string and (if applicable) may contain a chassis-version clock
> >>>>>         compatible string.
> >>>>>
> >>>>>         Chip-specific strings are of the form "fsl,<chip>-clockgen", such as:
> >>>>>         * "fsl,p2041-clockgen"
> >>>>>         * "fsl,p3041-clockgen"
> >>>>>         * "fsl,p4080-clockgen"
> >>>>>         * "fsl,p5020-clockgen"
> >>>>>         * "fsl,p5040-clockgen"
> >>>>>         * "fsl,t4240-clockgen"
> >>>>>         * "fsl,b4420-clockgen"
> >>>>>         * "fsl,b4860-clockgen"
> >>>>>         * "fsl,ls1021a-clockgen"
> >>>>>         Chassis-version clock strings include:
> >>>>>         * "fsl,qoriq-clockgen-1.0": for chassis 1.0 clocks
> >>>>>         * "fsl,qoriq-clockgen-2.0": for chassis 2.0 clocks
> >>>>>
> >>>>> I really hope we don't have to update every single
> >>>>> fsl,<chip>-whatever binding every time a new chip comes out.  There
> >>>>> are already other chips not listed, FWIW (e.g. t1040, t2080, ls1043a, and
> >ls2080a).  That's why it says "such as".
> >>>>
> >>>> If I remember correctly, DT maintainers want every supported
> >>>> compatible string explicitly listed in bindings doc.  And they even
> >>>> added a check into checkpatch.pl with commit bff5da433525
> >>>> ("checkpatch: add DT compatible string documentation checks").
> >>>
> >>> See Documentation/devicetree/bindings/submitting-patches.txt:
> >>>
> >>>   5) The wildcard "<chip>" may be used in compatible strings, as in
> >>>      the following example:
> >>>
> >>>          - compatible: Must contain '"nvidia,<chip>-pcie",
> >>>            "nvidia,tegra20-pcie"' where <chip> is tegra30, tegra132, ...
> >>>
> >>>      As in the above example, the known values of "<chip>" should be
> >>>      documented if it is used.
> >>>
> >>> It _is_ allowed to use the <chip> wildcard, and so you will not find
> >>> all full compatible strings explicitly listed in bindings.  However,
> >>> the chips themselves "should" be listed.
> >>
> >> + Rob and Mark
> >>
> >> Oops, I'm not aware of this DT document.  In that case, the DT
> >> document and checkpatch is basically asking for conflicting thing.
> >> Rob, Mark, can you guys please clarify?
> >
> >Checkpatch is a useful tool but it can't get everything right all the time.
> >
> 
> So what should we do, shall I add "compatible = "fsl,ls1012a-clockgen";" in Documentation/devicetree/bindings/clock/qoriq-clock.txt ?

I would encourage you to do that.

Shawn