mirror of https://github.com/torvalds/linux.git
115 lines
4.7 KiB
ReStructuredText
115 lines
4.7 KiB
ReStructuredText
.. SPDX-License-Identifier: GPL-2.0
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==========================================
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Submitting Devicetree (DT) binding patches
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==========================================
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I. For patch submitters
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=======================
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0) Normal patch submission rules from
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Documentation/process/submitting-patches.rst applies.
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1) The Documentation/ and include/dt-bindings/ portion of the patch should
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be a separate patch. The preferred subject prefix for binding patches is::
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"dt-bindings: <binding dir>: ..."
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Few subsystems, like ASoC, media, regulators and SPI, expect reverse order
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of the prefixes::
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"<binding dir>: dt-bindings: ..."
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The 80 characters of the subject are precious. It is recommended to not
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use "Documentation", "doc" or "YAML" because that is implied. All
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bindings are docs and all new bindings are supposed to be in Devicetree
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schema format. Repeating "binding" again should also be avoided, so for
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a new device it is often enough for example::
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"dt-bindings: iio: adc: Add ROHM BD79100G"
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Conversion of other formats to DT schema::
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"dt-bindings: iio: adc: adi,ad7476: Convert to DT schema"
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2) DT binding files are written in DT schema format using json-schema
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vocabulary and YAML file format. The DT binding files must pass validation
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by running::
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make dt_binding_check
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See Documentation/devicetree/bindings/writing-schema.rst for more details
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about schema and tools setup.
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3) DT binding files should be dual licensed. The preferred license tag is
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(GPL-2.0-only OR BSD-2-Clause).
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4) Submit the entire series to the devicetree mailinglist at
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devicetree@vger.kernel.org
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and Cc: the DT maintainers. Use scripts/get_maintainer.pl to identify
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all of the DT maintainers.
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5) The Documentation/ portion of the patch should come in the series before
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the code implementing the binding.
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6) Any compatible strings used in a chip or board DTS file must be
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previously documented in the corresponding DT binding file
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in Documentation/devicetree/bindings. This rule applies even if
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the Linux device driver does not yet match on the compatible
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string. [ checkpatch will emit warnings if this step is not
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followed as of commit bff5da4335256513497cc8c79f9a9d1665e09864
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("checkpatch: add DT compatible string documentation checks"). ]
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7) DTS is treated in general as driver-independent hardware description, thus
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any DTS patches, regardless whether using existing or new bindings, should
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be placed at the end of patchset to indicate no dependency of drivers on
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the DTS. DTS will be anyway applied through separate tree or branch, so
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different order would indicate the series is non-bisectable.
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If a driver subsystem maintainer prefers to apply entire set, instead of
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their relevant portion of patchset, please split the DTS patches into
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separate patchset with a reference in changelog or cover letter to the
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bindings submission on the mailing list.
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8) If a documented compatible string is not yet matched by the
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driver, the documentation should also include a compatible
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string that is matched by the driver.
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9) Bindings are actively used by multiple projects other than the Linux
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Kernel, extra care and consideration may need to be taken when making changes
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to existing bindings.
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II. For kernel maintainers
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==========================
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1) If you aren't comfortable reviewing a given binding, reply to it and ask
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the devicetree maintainers for guidance. This will help them prioritize
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which ones to review and which ones are ok to let go.
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2) For driver (not subsystem) bindings: If you are comfortable with the
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binding, and it hasn't received an Acked-by from the devicetree
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maintainers after a few weeks, go ahead and take it.
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For subsystem bindings (anything affecting more than a single device),
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getting a devicetree maintainer to review it is required.
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3) For a series going through multiple trees, the binding patch should be
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kept with the driver using the binding.
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4) The DTS files should however never be applied via driver subsystem tree,
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but always via platform SoC trees on dedicated branches (see also
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Documentation/process/maintainer-soc.rst).
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III. Notes
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==========
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0) Please see Documentation/devicetree/bindings/ABI.rst for details
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regarding devicetree ABI.
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1) This document is intended as a general familiarization with the process as
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decided at the 2013 Kernel Summit. When in doubt, the current word of the
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devicetree maintainers overrules this document. In that situation, a patch
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updating this document would be appreciated.
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