Re: [Ksummit-2013-discuss] DT bindings as ABI [was: Do we have people interested in device tree janitoring / cleanup?]

From: "Arend van Spriel" <arend@broadcom.com>
To: "jonsmirl@gmail.com" <jonsmirl@gmail.com>
Cc: "Mark Rutland" <mark.rutland@arm.com>,
	"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
	"ksummit-2013-discuss@lists.linuxfoundation.org" 
	<ksummit-2013-discuss@lists.linuxfoundation.org>,
	"Russell King - ARM Linux" <linux@arm.linux.org.uk>,
	"Ian Campbell" <ian.campbell@citrix.com>,
	"Pawel Moll" <Pawel.Moll@arm.com>,
	"Stephen Warren" <swarren@wwwdotorg.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"Richard Cochran" <richardcochran@gmail.com>,
	"Tomasz Figa" <tomasz.figa@gmail.com>,
	"rob.herring@calxeda.com" <rob.herring@calxeda.com>,
	"Domenico Andreoli" <cavokz@gmail.com>,
	"Grant Likely" <grant.likely@secretlab.ca>,
	"Dave P Martin" <Dave.Martin@arm.com>,
	"linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
	"Jason Gunthorpe" <jgunthorpe@obsidianresearch.com>
Subject: Re: [Ksummit-2013-discuss] DT bindings as ABI [was: Do we have people interested in device tree janitoring / cleanup?]
Date: Mon, 29 Jul 2013 12:16:10 +0200	[thread overview]
Message-ID: <51F640EA.7040509@broadcom.com> (raw)
In-Reply-To: <51F6338E.8020101@broadcom.com>

On 07/29/2013 11:19 AM, Arend van Spriel wrote:
> On 07/27/2013 10:01 PM, jonsmirl@gmail.com wrote:
>> On Sat, Jul 27, 2013 at 3:45 PM, Grant Likely
>> <grant.likely@secretlab.ca> wrote:
>>> On Sat, Jul 27, 2013 at 4:59 AM, Arend van Spriel
>>> <arend@broadcom.com> wrote:
>>>> Let's see how many people go and scream if I say this: Too bad .dts
>>>> files
>>>> are not done using XML format as DT bindings could be described
>>>> using XML
>>>> Schema.
>>>
>>> Draft an example and show us how it would look!  :-)  There is
>>> absolutely nothing preventing us from expressing a DT in XML format,
>>> or even using XSLT to define DT schema while still using our current
>>> .dts syntax. It would be trivial to do lossless translation between
>>> .dts syntax and xml.
>>>
>>> The problem that I have with XML and XSLT is that it is very verbose
>>> and not entirely friendly to mere-mortals. However, I'm more than
>>> willing to be proved wrong on this point.
>>
>> I considered this approach a while ago and discarded it. It would work
>> but it is just too much of a Frankenstein monster.
>
> Ah, but he is so cute. At least I do not think it is more monstrous as
> the bindings files. I just browsed through a couple of arm binding files
> as I felt challenged to come up with an example. I did not get the
> impression that there is some kind of template in place to get consitent
> bindings descriptions.
>
>> Much cleaner to modify dtc to take a schema as part of the compilation
>> process. The schema language itself has no requirement to look like
>> DTS syntax. Whoever wrote dtc probably has a favorite language that
>> would be good for writing schemas in.
>
> Not sure if I can follow here. I guess you mean the dts compilation,
> right? There are tools freely available to validate XML files against
> XSD specification files. As an example libxml2 has support for it. I
> suspect it is not desired to have a dependency for DTC with an
> out-of-tree library, but it could be incorporated and have DTC spew the
> validation results.

crap. Probably not as libxml2 has MIT-license.

Regards,
Arend