[PATCH] dt-bindings: Add running yamllint to dt_binding_check

[Rob Herring <robh@kernel.org>]

Add a yamllint config file and support for running yamllint on DT
binding schema files. This runs on the whole tree as yamllint is Python
and suffers from Python's slow startup times.

Users can run on individual files doing:

yamllint -c Documentation/devicetree/bindings/.yamllint <binding file>

Signed-off-by: Rob Herring <robh@kernel.org>
---
 Documentation/devicetree/bindings/.yamllint | 39 +++++++++++++++++++++
 Documentation/devicetree/bindings/Makefile  |  9 ++++-
 2 files changed, 47 insertions(+), 1 deletion(-)
 create mode 100644 Documentation/devicetree/bindings/.yamllint

diff --git a/Documentation/devicetree/bindings/.yamllint b/Documentation/devicetree/bindings/.yamllint
new file mode 100644
index 000000000000..214abd3ec440
--- /dev/null
+++ b/Documentation/devicetree/bindings/.yamllint
@@ -0,0 +1,39 @@
+extends: relaxed
+
+rules:
+  line-length:
+    # 80 chars should be enough, but don't fail if a line is longer
+    max: 110
+    allow-non-breakable-words: true
+    level: warning
+  braces:
+    min-spaces-inside: 0
+    max-spaces-inside: 1
+    min-spaces-inside-empty: 0
+    max-spaces-inside-empty: 0
+  brackets:
+    min-spaces-inside: 0
+    max-spaces-inside: 1
+    min-spaces-inside-empty: 0
+    max-spaces-inside-empty: 0
+  colons: {max-spaces-before: 0, max-spaces-after: 1}
+  commas: {min-spaces-after: 1, max-spaces-after: 1}
+  comments:
+    require-starting-space: false
+    min-spaces-from-content: 1
+  comments-indentation: disable
+  document-start:
+    present: true
+  empty-lines:
+    max: 3
+    max-end: 1
+  empty-values:
+    forbid-in-block-mappings: true
+    forbid-in-flow-mappings: true
+  hyphens:
+    max-spaces-after: 1
+  indentation:
+    spaces: 2
+    indent-sequences: true
+    check-multi-line-strings: false
+  trailing-spaces: false
diff --git a/Documentation/devicetree/bindings/Makefile b/Documentation/devicetree/bindings/Makefile
index ec8073cb2e71..f50420099a55 100644
--- a/Documentation/devicetree/bindings/Makefile
+++ b/Documentation/devicetree/bindings/Makefile
@@ -3,6 +3,8 @@ DT_DOC_CHECKER ?= dt-doc-validate
 DT_EXTRACT_EX ?= dt-extract-example
 DT_MK_SCHEMA ?= dt-mk-schema
 
+DT_SCHEMA_LINT = $(shell which yamllint)
+
 DT_SCHEMA_MIN_VERSION = 2020.8.1
 
 PHONY += check_dtschema_version
@@ -24,6 +26,10 @@ find_cmd = find $(srctree)/$(src) \( -name '*.yaml' ! \
 		-name 'processed-schema*' ! \
 		-name '*.example.dt.yaml' \)
 
+quiet_cmd_yamllint = LINT    $(src)
+      cmd_yamllint = $(find_cmd) | \
+                     xargs $(DT_SCHEMA_LINT) -f parsable -c $(srctree)/$(src)/.yamllint
+
 quiet_cmd_chk_bindings = CHKDT   $@
       cmd_chk_bindings = $(find_cmd) | \
                          xargs -n200 -P$$(nproc) $(DT_DOC_CHECKER) -u $(srctree)/$(src)
@@ -37,6 +43,7 @@ quiet_cmd_mk_schema = SCHEMA  $@
 		      rm -f $$f
 
 define rule_chkdt
+	$(if $(DT_SCHEMA_LINT),$(call cmd,yamllint),)
 	$(call cmd,chk_bindings)
 	$(call cmd,mk_schema)
 endef
@@ -48,7 +55,7 @@ override DTC_FLAGS := \
 	-Wno-graph_child_address \
 	-Wno-interrupt_provider
 
-$(obj)/processed-schema-examples.json: $(DT_DOCS) check_dtschema_version FORCE
+$(obj)/processed-schema-examples.json: $(DT_DOCS) $(src)/.yamllint check_dtschema_version FORCE
 	$(call if_changed_rule,chkdt)
 
 ifeq ($(DT_SCHEMA_FILES),)
-- 
2.25.1