[PATCH] kbuild: allow validating individual dtb files against schema

[Dmitry Baryshkov <dmitry.baryshkov@linaro.org>]

While it is possible to validate all generated dtb files against the
schema, it typically results in huge pile of warnings. While working on
a platform it is quite useful to validate just a single file against
schema.

Allow specifying CHECK_DTBS=1 on a make command line to enable
validation while building dtb files. This reuses the infrastructure
existing for `make dtbs_check`, making dtbs_check a shortcut for
`make CHECK_DTBS=1 dt_binding_check dtbs`.

Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Tom Rini <trini@konsulko.com>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: linux-kbuild@vger.kernel.org
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
---
 Makefile | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/Makefile b/Makefile
index 9aa7de1ca58f..f28507d2ee03 100644
--- a/Makefile
+++ b/Makefile
@@ -1464,10 +1464,14 @@ endif
 
 ifneq ($(dtstree),)
 
-%.dtb: include/config/kernel.release scripts_dtc
+ifneq ($(CHECK_DTBS),)
+DT_TMP_BINDING := dt_binding
+endif
+
+%.dtb: include/config/kernel.release scripts_dtc $(DT_TMP_BINDING)
 	$(Q)$(MAKE) $(build)=$(dtstree) $(dtstree)/$@
 
-%.dtbo: include/config/kernel.release scripts_dtc
+%.dtbo: include/config/kernel.release scripts_dtc $(DT_TMP_BINDING)
 	$(Q)$(MAKE) $(build)=$(dtstree) $(dtstree)/$@
 
 PHONY += dtbs dtbs_install dtbs_check
@@ -1498,8 +1502,10 @@ ifneq ($(filter dt_binding_check, $(MAKECMDGOALS)),)
 export CHECK_DT_BINDING=y
 endif
 
-PHONY += dt_binding_check
-dt_binding_check: scripts_dtc
+dt_binding_check: dt_binding
+
+PHONY += dt_binding
+dt_binding: scripts_dtc
 	$(Q)$(MAKE) $(build)=Documentation/devicetree/bindings
 
 # ---------------------------------------------------------------------------
@@ -1774,6 +1780,10 @@ help:
 	@echo  '		3: more obscure warnings, can most likely be ignored'
 	@echo  '		e: warnings are being treated as errors'
 	@echo  '		Multiple levels can be combined with W=12 or W=123'
+	@$(if $(dtstree), \
+		echo '  make CHECK_DTBS=1 [targets] Check all generated dtb files against schema'; \
+		echo '         This can be applied both to "dtbs" and to individual "foo.dtb" targets' ; \
+		)
 	@echo  ''
 	@echo  'Execute "make" or "make all" to build all targets marked with [*] '
 	@echo  'For further info see the ./README file'
-- 
2.35.1