xref: /linux/Documentation/devicetree/bindings/submitting-patches.rst (revision 5a558f369ef89c6fd8170ee1137274fcc08517ae)
1.. SPDX-License-Identifier: GPL-2.0
2
3==========================================
4Submitting Devicetree (DT) binding patches
5==========================================
6
7I. For patch submitters
8=======================
9
10  0) Normal patch submission rules from
11     Documentation/process/submitting-patches.rst applies.
12
13  1) The Documentation/ and include/dt-bindings/ portion of the patch should
14     be a separate patch. The preferred subject prefix for binding patches is::
15
16       "dt-bindings: <binding dir>: ..."
17
18     Few subsystems, like ASoC, media, regulators and SPI, expect reverse order
19     of the prefixes::
20
21       "<binding dir>: dt-bindings: ..."
22
23     The 80 characters of the subject are precious. It is recommended to not
24     use "Documentation" or "doc" because that is implied. All bindings are
25     docs. Repeating "binding" again should also be avoided.
26
27  2) DT binding files are written in DT schema format using json-schema
28     vocabulary and YAML file format. The DT binding files must pass validation
29     by running::
30
31       make dt_binding_check
32
33     See Documentation/devicetree/bindings/writing-schema.rst for more details
34     about schema and tools setup.
35
36  3) DT binding files should be dual licensed. The preferred license tag is
37     (GPL-2.0-only OR BSD-2-Clause).
38
39  4) Submit the entire series to the devicetree mailinglist at
40
41       devicetree@vger.kernel.org
42
43     and Cc: the DT maintainers. Use scripts/get_maintainer.pl to identify
44     all of the DT maintainers.
45
46  5) The Documentation/ portion of the patch should come in the series before
47     the code implementing the binding.
48
49  6) Any compatible strings used in a chip or board DTS file must be
50     previously documented in the corresponding DT binding file
51     in Documentation/devicetree/bindings.  This rule applies even if
52     the Linux device driver does not yet match on the compatible
53     string.  [ checkpatch will emit warnings if this step is not
54     followed as of commit bff5da4335256513497cc8c79f9a9d1665e09864
55     ("checkpatch: add DT compatible string documentation checks"). ]
56
57  7) If a documented compatible string is not yet matched by the
58     driver, the documentation should also include a compatible
59     string that is matched by the driver.
60
61  8) Bindings are actively used by multiple projects other than the Linux
62     Kernel, extra care and consideration may need to be taken when making changes
63     to existing bindings.
64
65II. For kernel maintainers
66==========================
67
68  1) If you aren't comfortable reviewing a given binding, reply to it and ask
69     the devicetree maintainers for guidance.  This will help them prioritize
70     which ones to review and which ones are ok to let go.
71
72  2) For driver (not subsystem) bindings: If you are comfortable with the
73     binding, and it hasn't received an Acked-by from the devicetree
74     maintainers after a few weeks, go ahead and take it.
75
76     For subsystem bindings (anything affecting more than a single device),
77     getting a devicetree maintainer to review it is required.
78
79  3) For a series going though multiple trees, the binding patch should be
80     kept with the driver using the binding.
81
82III. Notes
83==========
84
85  0) Please see Documentation/devicetree/bindings/ABI.rst for details
86     regarding devicetree ABI.
87
88  1) This document is intended as a general familiarization with the process as
89     decided at the 2013 Kernel Summit.  When in doubt, the current word of the
90     devicetree maintainers overrules this document.  In that situation, a patch
91     updating this document would be appreciated.
92