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authorRob Herring <robh@kernel.org>2014-01-23 08:23:04 -0600
committerRob Herring <robh@kernel.org>2014-01-23 08:23:04 -0600
commit619d144013cb30a19d1dfa8294fbe29fcc2c2363 (patch)
treefa98b07a2d7062b40759d1b969f6aef6ae7cf409 /Documentation
parent9b9900aa60e271a0c64fd1e16beb07e341e7d626 (diff)
parent2a9330010bea5982a5c6593824bc036bf62d67b7 (diff)
Merge remote-tracking branch 'grant/devicetree/next' into for-3.14
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/devicetree/bindings/ABI.txt39
-rw-r--r--Documentation/devicetree/bindings/submitting-patches.txt38
2 files changed, 77 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/ABI.txt b/Documentation/devicetree/bindings/ABI.txt
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+
+ Devicetree (DT) ABI
+
+I. Regarding stable bindings/ABI, we quote from the 2013 ARM mini-summit
+ summary document:
+
+ "That still leaves the question of, what does a stable binding look
+ like? Certainly a stable binding means that a newer kernel will not
+ break on an older device tree, but that doesn't mean the binding is
+ frozen for all time. Grant said there are ways to change bindings that
+ don't result in breakage. For instance, if a new property is added,
+ then default to the previous behaviour if it is missing. If a binding
+ truly needs an incompatible change, then change the compatible string
+ at the same time. The driver can bind against both the old and the
+ new. These guidelines aren't new, but they desperately need to be
+ documented."
+
+II. General binding rules
+
+ 1) Maintainers, don't let perfect be the enemy of good. Don't hold up a
+ binding because it isn't perfect.
+
+ 2) Use specific compatible strings so that if we need to add a feature (DMA)
+ in the future, we can create a new compatible string. See I.
+
+ 3) Bindings can be augmented, but the driver shouldn't break when given
+ the old binding. ie. add additional properties, but don't change the
+ meaning of an existing property. For drivers, default to the original
+ behaviour when a newly added property is missing.
+
+ 4) Don't submit bindings for staging or unstable. That will be decided by
+ the devicetree maintainers *after* discussion on the mailinglist.
+
+III. Notes
+
+ 1) This document is intended as a general familiarization with the process as
+ decided at the 2013 Kernel Summit. When in doubt, the current word of the
+ devicetree maintainers overrules this document. In that situation, a patch
+ updating this document would be appreciated.
diff --git a/Documentation/devicetree/bindings/submitting-patches.txt b/Documentation/devicetree/bindings/submitting-patches.txt
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index 000000000000..042a0273b8ba
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+
+ Submitting devicetree (DT) binding patches
+
+I. For patch submitters
+
+ 0) Normal patch submission rules from Documentation/SubmittingPatches
+ applies.
+
+ 1) The Documentation/ portion of the patch should be a separate patch.
+
+ 2) Submit the entire series to the devicetree mailinglist at
+
+ devicetree@vger.kernel.org
+
+II. For kernel maintainers
+
+ 1) If you aren't comfortable reviewing a given binding, reply to it and ask
+ the devicetree maintainers for guidance. This will help them prioritize
+ which ones to review and which ones are ok to let go.
+
+ 2) For driver (not subsystem) bindings: If you are comfortable with the
+ binding, and it hasn't received an Acked-by from the devicetree
+ maintainers after a few weeks, go ahead and take it.
+
+ Subsystem bindings (anything affecting more than a single device)
+ then getting a devicetree maintainer to review it is required.
+
+ 3) For a series going though multiple trees, the binding patch should be
+ kept with the driver using the binding.
+
+III. Notes
+
+ 0) Please see ...bindings/ABI.txt for details regarding devicetree ABI.
+
+ 1) This document is intended as a general familiarization with the process as
+ decided at the 2013 Kernel Summit. When in doubt, the current word of the
+ devicetree maintainers overrules this document. In that situation, a patch
+ updating this document would be appreciated.

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