[PATCH] kbuild: Add DTB_FILES variable for dtbs_check

["Nícolas F. R. A. Prado" <nfraprado@collabora.com>]

Currently running dtbs_check compiles and runs the DT checker on all
enabled devicetrees against all dt-bindings. This can take a long time,
and is an unnecessary burden when just validating a new devicetree or
changes in an existing one, with the dt-bindings unchanged.

Similarly to DT_SCHEMA_FILES for dt_binding_check, add a DTB_FILES
variable that can be passed to the dtbs_check make command to restrict
which devicetrees are validated.

Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>

---
Usage example:
make dtbs_check DTB_FILES='arch/arm64/boot/dts/mediatek/mt8192-asurada-spherion-r0.dtb arch/arm64/boot/dts/mediatek/mt8192-asurada-hayato-r1.dtb'

 scripts/Makefile.lib | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index ec391c6a2641..f3ac6d3632a2 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -418,9 +418,16 @@ DT_CHECKER_FLAGS ?= $(if $(DT_SCHEMA_FILES),-l $(DT_SCHEMA_FILES),-m)
 DT_BINDING_DIR := Documentation/devicetree/bindings
 DT_TMP_SCHEMA := $(objtree)/$(DT_BINDING_DIR)/processed-schema.json
 
+ifeq ($(DTB_FILES),)
 quiet_cmd_dtb =	DTC_CHK $@
       cmd_dtb =	$(cmd_dtc) ; $(DT_CHECKER) $(DT_CHECKER_FLAGS) -u $(srctree)/$(DT_BINDING_DIR) -p $(DT_TMP_SCHEMA) $@ || true
 else
+SHOULD_CHECK_DTB = $(filter $@,$(DTB_FILES))
+
+quiet_cmd_dtb =	$(if $(SHOULD_CHECK_DTB),DTC_CHK,DTC) $@
+      cmd_dtb =	$(if $(SHOULD_CHECK_DTB), $(cmd_dtc) ; $(DT_CHECKER) $(DT_CHECKER_FLAGS) -u $(srctree)/$(DT_BINDING_DIR) -p $(DT_TMP_SCHEMA) $@ || true , $(cmd_dtc))
+endif
+else
 quiet_cmd_dtb = $(quiet_cmd_dtc)
       cmd_dtb = $(cmd_dtc)
 endif
-- 
2.38.1