From: swarren@wwwdotorg•org (Stephen Warren)
To: linux-arm-kernel@lists•infradead.org
Subject: DT bindings as ABI [was: Do we have people interested in device tree janitoring / cleanup?]
Date: Thu, 25 Jul 2013 11:05:48 -0700 [thread overview]
Message-ID: <51F168FC.9070906@wwwdotorg.org> (raw)
In-Reply-To: <20130725175702.GC22291@e106331-lin.cambridge.arm.com>
On 07/25/2013 10:57 AM, Mark Rutland wrote:
> On Thu, Jul 25, 2013 at 05:09:19PM +0100, Olof Johansson wrote:
...
>> So, there really seems to be a need for a layered approach, one in
>> which a binding "graduates" from being tentative to being locked in.
>> I'm refraining from using the terms "staging" and "stable" here, since
>> they have overloaded meaning in the kernel world that doesn't apply
>> here.
>
> I'm not sure how realistic it is to have drivers in the kernel using
> unstable bindings, and expect people to not rely on them, but I don't
> have a better option to give. We need a big fat warning that an unstable
> binding is in use.
I don't think having people "rely" on the bindings is the issue so much
as the awareness that if they do, there will be compatibility issues for
unstable bindings.
>> One problem that needs to be solved is obviously how a binding
>> graduates from tentative to locked. This work isn't going to be very
>> interesting to most people, I suspect. Think standards committee type
>> work.
>>
>> A possible way to handle this is to have exactly that: A group of
>> people that essentially constitute the "standards committee" that meet
>> on a regular basis to review and approve new bindings. They should be
>> people not just doing ARM Linux work, but other stakeholders in these
>> bindings too. One of the things they should probably do is sift
>> through our current in-kernel bindings and select those who seem ready
>> to be locked in, review/discuss/decide upon that and once the decision
>> is made, that specific binding does become part of the static,
>> never-ever-change ABI of firmware-to-kernel interfaces. That might
>> also be the time that the binding is moved from the kernel to a
>> separate repo, but that's a technicality that we'll let the DT
>> maintainers decide among themselves, IMHO.
>
> We're going to need input from other OSs too, or the bindings will
> remain Linux-specific regardless of how far away the bindings and dts
> repo(s) is/are.
And bootloaders too. Some U-Boot platforms are starting to use DT for
exactly the same reason that the kernel does; to allow a single
bootloader binary to run on a variety of different boards, with all
configuration coming from DT.
On another related topic, something that may be useful for the DT
bindings reviewer team is a basic checklist for new DT bindings.
Something similar to Fedora's package review checklist. Perhaps also
(yet another?) document on a bit of DT philosophy. If this sounds
useful, I could try and take a stab at some basic initial version.
We also need to decide (or just document) exactly what "describes the
HW" means; see the thread on thermal limits, and consider the extension
of describing hard/absolute thermal limits to describing use-cased base
thermal profiles using the same schema, or not allowing that.
next prev parent reply other threads:[~2013-07-25 18:05 UTC|newest]
Thread overview: 142+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-25 16:09 DT bindings as ABI [was: Do we have people interested in device tree janitoring / cleanup?] Olof Johansson
2013-07-25 17:57 ` Mark Rutland
2013-07-25 18:05 ` Stephen Warren [this message]
2013-07-25 18:25 ` Olof Johansson
2013-07-25 18:50 ` Stephen Warren
2013-07-25 19:30 ` [Ksummit-2013-discuss] " Mark Brown
2013-07-25 18:29 ` Mark Rutland
2013-07-25 18:48 ` Richard Cochran
2013-07-25 18:53 ` Stephen Warren
2013-07-25 21:41 ` Domenico Andreoli
2013-07-26 4:43 ` Richard Cochran
2013-07-25 21:37 ` Jason Gunthorpe
2013-07-26 4:54 ` Richard Cochran
2013-07-26 13:42 ` Rob Herring
2013-07-26 17:15 ` Jason Gunthorpe
2013-07-27 8:48 ` Richard Cochran
2013-07-27 10:40 ` [Ksummit-2013-discuss] " Mark Brown
2013-07-27 17:37 ` Richard Cochran
2013-07-27 17:57 ` David Lang
2013-07-27 18:17 ` Richard Cochran
2013-07-28 11:27 ` Mark Brown
2013-07-29 17:54 ` Jason Gunthorpe
2013-07-29 18:16 ` Russell King - ARM Linux
2013-07-29 18:40 ` Jason Gunthorpe
2013-07-27 8:53 ` Richard Cochran
2013-07-27 10:20 ` Tomasz Figa
2013-07-27 11:36 ` [Ksummit-2013-discuss] " Mark Brown
2013-07-27 18:07 ` Richard Cochran
2013-07-28 12:10 ` Mark Brown
2013-07-26 8:01 ` Richard Cochran
2013-07-26 9:42 ` [Ksummit-2013-discuss] " David Woodhouse
2013-07-26 13:09 ` Richard Cochran
2013-07-26 13:14 ` Russell King - ARM Linux
2013-07-27 15:28 ` David Gibson
2013-07-26 13:27 ` Jason Cooper
2013-07-26 13:38 ` Russell King - ARM Linux
2013-07-26 13:45 ` Jason Cooper
2013-07-26 13:50 ` David Woodhouse
2013-07-26 13:59 ` Jason Cooper
2013-07-26 13:41 ` David Woodhouse
2013-07-26 13:47 ` Jason Cooper
2013-07-26 14:14 ` jonsmirl at gmail.com
2013-07-26 14:16 ` David Woodhouse
2013-07-26 14:21 ` Russell King - ARM Linux
2013-07-26 14:39 ` jonsmirl at gmail.com
2013-07-26 14:40 ` Mark Brown
2013-07-29 15:32 ` Matt Porter
2013-07-27 15:19 ` David Gibson
2013-07-27 19:37 ` Grant Likely
2013-07-27 9:16 ` Ming Lei
2013-07-26 14:10 ` Mark Brown
2013-07-26 15:49 ` Olof Johansson
2013-07-26 16:36 ` Rob Herring
2013-07-27 4:57 ` Richard Cochran
2013-07-27 5:04 ` Richard Cochran
2013-07-27 9:51 ` Tomasz Figa
2013-07-27 10:24 ` Arend van Spriel
2013-07-27 10:34 ` Arend van Spriel
2013-07-27 11:09 ` Russell King - ARM Linux
2013-07-27 10:36 ` Tomasz Figa
2013-07-27 10:59 ` Arend van Spriel
2013-07-27 19:45 ` Grant Likely
2013-07-27 20:01 ` jonsmirl at gmail.com
2013-07-27 20:03 ` David Woodhouse
2013-07-27 20:25 ` Grant Likely
2013-07-28 3:28 ` Grant Likely
2013-07-28 5:11 ` James Bottomley
2013-07-28 5:13 ` Grant Likely
2013-07-30 1:44 ` David Gibson
2013-07-30 2:15 ` jonsmirl at gmail.com
2013-07-30 3:29 ` David Gibson
2013-07-30 4:35 ` Grant Likely
2013-07-30 8:39 ` Maxime Ripard
2013-07-30 16:30 ` Stephen Warren
2013-07-30 17:27 ` John W. Linville
2013-07-30 16:40 ` Stephen Warren
2013-07-29 9:19 ` Arend van Spriel
2013-07-29 10:16 ` Arend van Spriel
2013-07-27 18:31 ` Richard Cochran
2013-07-27 18:51 ` Tomasz Figa
2013-07-27 19:22 ` jonsmirl at gmail.com
2013-07-28 8:56 ` Richard Cochran
2013-07-28 9:12 ` Tomasz Figa
2013-07-28 13:19 ` Richard Cochran
2013-07-28 13:39 ` Tomasz Figa
2013-07-28 14:09 ` jonsmirl at gmail.com
2013-07-28 15:35 ` Richard Cochran
2013-07-28 15:50 ` jonsmirl at gmail.com
2013-07-28 17:41 ` Mark Brown
2013-07-28 21:46 ` David Gibson
2013-07-28 15:30 ` Richard Cochran
2013-07-29 7:31 ` Maxime Ripard
2013-07-29 18:38 ` Richard Cochran
2013-07-29 18:51 ` Richard Cochran
2013-07-29 18:05 ` Jason Gunthorpe
2013-07-29 18:27 ` Russell King - ARM Linux
2013-07-29 22:20 ` David Gibson
2013-07-29 23:14 ` Jason Gunthorpe
2013-07-29 23:49 ` David Gibson
2013-07-31 10:37 ` Maxime Bizon
2013-07-31 10:59 ` Tomasz Figa
2013-07-31 15:07 ` Richard Cochran
2013-07-31 15:23 ` Tomasz Figa
2013-07-31 19:12 ` Richard Cochran
2013-07-31 19:29 ` Tomasz Figa
2013-07-31 20:00 ` Richard Cochran
2013-07-31 20:14 ` Russell King - ARM Linux
2013-07-31 20:37 ` jonsmirl at gmail.com
2013-07-31 20:48 ` Russell King - ARM Linux
2013-07-31 21:26 ` jonsmirl at gmail.com
2013-08-01 9:57 ` Arend van Spriel
2013-08-01 10:09 ` Mark Brown
2013-08-01 10:18 ` David Woodhouse
2013-08-01 13:34 ` jonsmirl at gmail.com
2013-08-01 13:43 ` jonsmirl at gmail.com
2013-08-01 13:48 ` Rob Herring
2013-08-02 3:50 ` David Gibson
2013-08-13 23:32 ` H. Peter Anvin
2013-08-14 1:49 ` Guenter Roeck
2013-08-14 14:46 ` H. Peter Anvin
2013-08-02 8:49 ` Tony Lindgren
2013-07-29 15:45 ` Matt Porter
2013-07-31 12:58 ` Ian Campbell
2013-07-25 17:59 ` Stephen Warren
2013-07-25 19:11 ` Rob Herring
2013-07-25 19:31 ` Jason Cooper
2013-07-25 20:04 ` [Ksummit-2013-discuss] " Mark Brown
2013-07-25 20:08 ` Jason Cooper
2013-07-25 20:16 ` Rob Herring
2013-07-25 20:32 ` Jason Cooper
2013-07-25 21:53 ` [Ksummit-2013-discuss] " Ben Hutchings
2013-07-26 0:36 ` Stephen Warren
2013-07-26 12:14 ` Jason Cooper
2013-07-26 0:34 ` Stephen Warren
2013-07-26 22:11 ` Rob Herring
2013-07-25 23:18 ` Russell King - ARM Linux
2013-07-26 0:27 ` jonsmirl at gmail.com
2013-07-26 11:38 ` Jason Cooper
2013-07-26 14:08 ` [Ksummit-2013-discuss] " David Woodhouse
2013-07-26 13:57 ` Mark Brown
2013-07-26 10:55 ` Mark Brown
2013-07-28 4:39 ` Grant Likely
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