kbuild: Always validate DT binding examples

Most folks only run dt_binding_check on the single schema they care about
by setting DT_SCHEMA_FILES. That means example is only checked against
that one schema which is not always sufficient.

Let's address this by splitting processed-schema.yaml into 2 files: one
that's always all schemas for the examples and one that's just the schema
in DT_SCHEMA_FILES for dtbs.
Co-developed-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Documentation/devicetree/bindings/.gitignore

 *.example.dts
-processed-schema.yaml
+processed-schema*.yaml

Documentation/devicetree/bindings/Makefile

@@ -2,7 +2,6 @@
 DT_DOC_CHECKER ?= dt-doc-validate
 DT_EXTRACT_EX ?= dt-extract-example
 DT_MK_SCHEMA ?= dt-mk-schema
-DT_MK_SCHEMA_FLAGS := $(if $(DT_SCHEMA_FILES), -u)
 
 quiet_cmd_chk_binding = CHKDT   $(patsubst $(srctree)/%,%,$<)
       cmd_chk_binding = $(DT_DOC_CHECKER) -u $(srctree)/$(src) $< ; \
@@ -11,26 +10,33 @@ quiet_cmd_chk_binding = CHKDT   $(patsubst $(srctree)/%,%,$<)
 $(obj)/%.example.dts: $(src)/%.yaml FORCE
 	$(call if_changed,chk_binding)
 
-DT_TMP_SCHEMA := processed-schema.yaml
+# Use full schemas when checking %.example.dts
+DT_TMP_SCHEMA := $(obj)/processed-schema-examples.yaml
 
 quiet_cmd_mk_schema = SCHEMA  $@
       cmd_mk_schema = $(DT_MK_SCHEMA) $(DT_MK_SCHEMA_FLAGS) -o $@ $(real-prereqs)
 
-DT_DOCS = $(shell \
+DT_DOCS = $(addprefix $(src)/, \
+	$(shell \
 	cd $(srctree)/$(src) && \
 	find * \( -name '*.yaml' ! \
-		-name $(DT_TMP_SCHEMA) ! \
+		-name 'processed-schema*' ! \
 		-name '*.example.dt.yaml' \) \
-	)
+	))
 
-DT_SCHEMA_FILES ?= $(addprefix $(src)/,$(DT_DOCS))
+DT_SCHEMA_FILES ?= $(DT_DOCS)
 
 ifeq ($(CHECK_DTBS),)
 extra-y += $(patsubst $(src)/%.yaml,%.example.dts, $(DT_SCHEMA_FILES))
 extra-y += $(patsubst $(src)/%.yaml,%.example.dt.yaml, $(DT_SCHEMA_FILES))
+extra-y += processed-schema-examples.yaml
+
+$(obj)/processed-schema-examples.yaml: $(DT_DOCS) FORCE
+	$(call if_changed,mk_schema)
 endif
 
-$(obj)/$(DT_TMP_SCHEMA): $(DT_SCHEMA_FILES) FORCE
+$(obj)/processed-schema.yaml: DT_MK_SCHEMA_FLAGS := -u
+$(obj)/processed-schema.yaml: $(DT_SCHEMA_FILES) FORCE
 	$(call if_changed,mk_schema)
 
-extra-y += $(DT_TMP_SCHEMA)
+extra-y += processed-schema.yaml

scripts/Makefile.lib

@@ -297,7 +297,8 @@ $(obj)/%.dtb: $(src)/%.dts $(DTC) FORCE
 
 DT_CHECKER ?= dt-validate
 DT_BINDING_DIR := Documentation/devicetree/bindings
-DT_TMP_SCHEMA := $(objtree)/$(DT_BINDING_DIR)/processed-schema.yaml
+# DT_TMP_SCHEMA may be overridden from Documentation/devicetree/bindings/Makefile
+DT_TMP_SCHEMA ?= $(objtree)/$(DT_BINDING_DIR)/processed-schema.yaml
 
 quiet_cmd_dtb_check =	CHECK   $@
       cmd_dtb_check =	$(DT_CHECKER) -u $(srctree)/$(DT_BINDING_DIR) -p $(DT_TMP_SCHEMA) $@