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 Documentation/process/submitting-patches.rst 11 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 The 80 characters of the subject are precious. It is recommended to not 19 use "Documentation" or "doc" because that is implied. All bindings are 20 docs. Repeating "binding" again should also be avoided. 21 22 2) DT binding files are written in DT schema format using json-schema 23 vocabulary and YAML file format. The DT binding files must pass validation 24 by running:: 25 26 make dt_binding_check 27 28 See ../writing-schema.rst for more details about schema and tools setup. 29 30 3) DT binding files should be dual licensed. The preferred license tag is 31 (GPL-2.0-only OR BSD-2-Clause). 32 33 4) Submit the entire series to the devicetree mailinglist at 34 35 devicetree@vger.kernel.org 36 37 and Cc: the DT maintainers. Use scripts/get_maintainer.pl to identify 38 all of the DT maintainers. 39 40 5) The Documentation/ portion of the patch should come in the series before 41 the code implementing the binding. 42 43 6) Any compatible strings used in a chip or board DTS file must be 44 previously documented in the corresponding DT binding text file 45 in Documentation/devicetree/bindings. This rule applies even if 46 the Linux device driver does not yet match on the compatible 47 string. [ checkpatch will emit warnings if this step is not 48 followed as of commit bff5da4335256513497cc8c79f9a9d1665e09864 49 ("checkpatch: add DT compatible string documentation checks"). ] 50 51 7) The wildcard "<chip>" may be used in compatible strings, as in 52 the following example: 53 54 - compatible: Must contain '"nvidia,<chip>-pcie", 55 "nvidia,tegra20-pcie"' where <chip> is tegra30, tegra132, ... 56 57 As in the above example, the known values of "<chip>" should be 58 documented if it is used. 59 60 8) If a documented compatible string is not yet matched by the 61 driver, the documentation should also include a compatible 62 string that is matched by the driver (as in the "nvidia,tegra20-pcie" 63 example above). 64 65 66II. For kernel maintainers 67========================== 68 69 1) If you aren't comfortable reviewing a given binding, reply to it and ask 70 the devicetree maintainers for guidance. This will help them prioritize 71 which ones to review and which ones are ok to let go. 72 73 2) For driver (not subsystem) bindings: If you are comfortable with the 74 binding, and it hasn't received an Acked-by from the devicetree 75 maintainers after a few weeks, go ahead and take it. 76 77 Subsystem bindings (anything affecting more than a single device) 78 then getting a devicetree maintainer to review it is required. 79 80 3) For a series going though multiple trees, the binding patch should be 81 kept with the driver using the binding. 82 83III. Notes 84========== 85 86 0) Please see ...bindings/ABI.txt for details 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