[PATCH v2 0/3] dt-bindings: automated coding style check for DTS examples

Daniel Golle
2026-04-29T14:21:42Z

v1: https://lore.kernel.org/all/cover.1776700167.git.daniel@makrotopia.org/

Following v1 review feedback, this series replaces the original
single-mode checker with one organised around a declarative rule
registry. Each rule is tagged 'relaxed' (default; must be
zero-violation on the current tree) or 'strict' (opt-in for new
submissions); promoting a rule from strict to relaxed is a one-line
edit once the tree catches up.

Default mode runs cleanly on the current tree once the small prep
series [1] has landed. Stricter rules (indent unit, property
ordering, blank-line placement, sibling address ordering, unused
labels, line length, value rendering, ...) live behind --mode=strict
and are intended for use by checkpatch.pl in a follow-up series.

The tool also accepts .dts/.dtsi/.dtso files directly (with a
tab-indent rule) so it can be reused for actual device tree sources.
It reads file paths from @argfile and parallelises across CPUs, with
$PARALLELISM (set by scripts/jobserver-exec) honoured so the worker
count tracks `make -j N`. ruamel.yaml is the only non-stdlib
dependency, already required by dtschema.

In aggregate, strict mode pins down indentation, blank lines,
property and child ordering, hex casing, unit-address format,
whitespace inside <...>, line length (80 cols), continuation
alignment, closing brace placement and unused labels -- enough to
drive a single canonical layout per DT structure modulo the
author's choice of when to wrap properties for readability.

Strict-mode violation counts on a current tree (5506 YAML bindings,
6530 in-tree .dts/.dtsi/.dtso under arch/):

rule yaml dts
property-order 14457 240804
indent-consistent 2435 294778
continuation-alignment 2462 187914
unused-labels 3611 11628
required-blank-lines 1862 47351
line-length 102 25999
child-name-order 664 16409
mixed-indent-chars 0 13275
indent-unit-strict 1493 --
child-address-order 69 4075
blank-lines 91 1963
value-whitespace 87 983
node-close-alone 40 783
hex-case 78 666
indent-unit 181 --
indent-unit-dts -- 202
unit-address-format 5 39
trailing-whitespace 0 10

(YAML and DTS columns reflect the rules that apply to each input
type; e.g. indent-unit-strict is YAML-only since .dts files use
tabs, indent-unit-dts is the equivalent DTS-only check.
unused-labels is skipped for .dtsi/.dtso since labels there are
exported to includers/applies-to.)

The script was written with generous help from Claude Opus 4.7,
since my Python is even worse than my DTS coding style.

[1] https://lore.kernel.org/all/cover.1777434096.git.daniel@makrotopia.org/

Daniel Golle (3):
dt-bindings: add DTS style checker
dt-bindings: wire style checker into dt_binding_check
dt-bindings: add self-test fixtures for style checker

Documentation/devicetree/bindings/Makefile | 20 +-
Makefile | 6 +
scripts/dtc/dt-check-style | 1063 +++++++++++++++++
.../dtc/dt-style-selftest/bad/dts-spaces.dts | 13 +
.../bad/yaml-child-addr-order.yaml | 41 +
.../bad/yaml-child-name-order.yaml | 37 +
.../bad/yaml-cont-align.yaml | 30 +
.../dt-style-selftest/bad/yaml-hex-case.yaml | 29 +
.../bad/yaml-indent-strict.yaml | 29 +
.../bad/yaml-line-length.yaml | 29 +
.../bad/yaml-mixed-indent.yaml | 29 +
.../bad/yaml-node-close.yaml | 31 +
.../bad/yaml-prop-order.yaml | 29 +
.../bad/yaml-prop-pairing.yaml | 33 +
.../bad/yaml-required-blank.yaml | 33 +
.../dtc/dt-style-selftest/bad/yaml-tab.yaml | 29 +
.../bad/yaml-trailing-ws.yaml | 29 +
.../dt-style-selftest/bad/yaml-unit-addr.yaml | 29 +
.../bad/yaml-unused-label.yaml | 29 +
.../dt-style-selftest/bad/yaml-value-ws.yaml | 29 +
.../expected/dts-spaces.dts.txt | 2 +
.../expected/yaml-child-addr-order.yaml.txt | 2 +
.../expected/yaml-child-name-order.yaml.txt | 2 +
.../expected/yaml-cont-align.yaml.txt | 2 +
.../expected/yaml-hex-case.yaml.txt | 2 +
.../expected/yaml-indent-strict.yaml.txt | 2 +
.../expected/yaml-line-length.yaml.txt | 2 +
.../expected/yaml-mixed-indent.yaml.txt | 3 +
.../expected/yaml-node-close.yaml.txt | 2 +
.../expected/yaml-prop-order.yaml.txt | 2 +
.../expected/yaml-prop-pairing.yaml.txt | 3 +
.../expected/yaml-required-blank.yaml.txt | 3 +
.../expected/yaml-tab.yaml.txt | 2 +
.../expected/yaml-trailing-ws.yaml.txt | 2 +
.../expected/yaml-unit-addr.yaml.txt | 2 +
.../expected/yaml-unused-label.yaml.txt | 2 +
.../expected/yaml-value-ws.yaml.txt | 2 +
.../dtc/dt-style-selftest/good/dts-tab.dts | 30 +
.../dt-style-selftest/good/yaml-4space.yaml | 41 +
scripts/dtc/dt-style-selftest/run.sh | 67 ++
40 files changed, 1770 insertions(+), 2 deletions(-)
create mode 100755 scripts/dtc/dt-check-style
create mode 100644 scripts/dtc/dt-style-selftest/bad/dts-spaces.dts
create mode 100644 scripts/dtc/dt-style-selftest/bad/yaml-child-addr-order.yaml
create mode 100644 scripts/dtc/dt-style-selftest/bad/yaml-child-name-order.yaml
create mode 100644 scripts/dtc/dt-style-selftest/bad/yaml-cont-align.yaml
create mode 100644 scripts/dtc/dt-style-selftest/bad/yaml-hex-case.yaml
create mode 100644 scripts/dtc/dt-style-selftest/bad/yaml-indent-strict.yaml
create mode 100644 scripts/dtc/dt-style-selftest/bad/yaml-line-length.yaml
create mode 100644 scripts/dtc/dt-style-selftest/bad/yaml-mixed-indent.yaml
create mode 100644 scripts/dtc/dt-style-selftest/bad/yaml-node-close.yaml
create mode 100644 scripts/dtc/dt-style-selftest/bad/yaml-prop-order.yaml
create mode 100644 scripts/dtc/dt-style-selftest/bad/yaml-prop-pairing.yaml
create mode 100644 scripts/dtc/dt-style-selftest/bad/yaml-required-blank.yaml
create mode 100644 scripts/dtc/dt-style-selftest/bad/yaml-tab.yaml
create mode 100644 scripts/dtc/dt-style-selftest/bad/yaml-trailing-ws.yaml
create mode 100644 scripts/dtc/dt-style-selftest/bad/yaml-unit-addr.yaml
create mode 100644 scripts/dtc/dt-style-selftest/bad/yaml-unused-label.yaml
create mode 100644 scripts/dtc/dt-style-selftest/bad/yaml-value-ws.yaml
create mode 100644 scripts/dtc/dt-style-selftest/expected/dts-spaces.dts.txt
create mode 100644 scripts/dtc/dt-style-selftest/expected/yaml-child-addr-order.yaml.txt
create mode 100644 scripts/dtc/dt-style-selftest/expected/yaml-child-name-order.yaml.txt
create mode 100644 scripts/dtc/dt-style-selftest/expected/yaml-cont-align.yaml.txt
create mode 100644 scripts/dtc/dt-style-selftest/expected/yaml-hex-case.yaml.txt
create mode 100644 scripts/dtc/dt-style-selftest/expected/yaml-indent-strict.yaml.txt
create mode 100644 scripts/dtc/dt-style-selftest/expected/yaml-line-length.yaml.txt
create mode 100644 scripts/dtc/dt-style-selftest/expected/yaml-mixed-indent.yaml.txt
create mode 100644 scripts/dtc/dt-style-selftest/expected/yaml-node-close.yaml.txt
create mode 100644 scripts/dtc/dt-style-selftest/expected/yaml-prop-order.yaml.txt
create mode 100644 scripts/dtc/dt-style-selftest/expected/yaml-prop-pairing.yaml.txt
create mode 100644 scripts/dtc/dt-style-selftest/expected/yaml-required-blank.yaml.txt
create mode 100644 scripts/dtc/dt-style-selftest/expected/yaml-tab.yaml.txt
create mode 100644 scripts/dtc/dt-style-selftest/expected/yaml-trailing-ws.yaml.txt
create mode 100644 scripts/dtc/dt-style-selftest/expected/yaml-unit-addr.yaml.txt
create mode 100644 scripts/dtc/dt-style-selftest/expected/yaml-unused-label.yaml.txt
create mode 100644 scripts/dtc/dt-style-selftest/expected/yaml-value-ws.yaml.txt
create mode 100644 scripts/dtc/dt-style-selftest/good/dts-tab.dts
create mode 100644 scripts/dtc/dt-style-selftest/good/yaml-4space.yaml
create mode 100755 scripts/dtc/dt-style-selftest/run.sh

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2.54.0