[PATCH] dt-bindings: fix wrong use of if_changed_rule

[Masahiro Yamada <masahiroy@kernel.org>]

The intent for if_changed_rule is to re-run the rule when the command
line is changed, but this if_changed_rule does not do anything for it.

$(cmd-check) for this rule is always empty because:

 [1] $(cmd_$@) is empty because .processed-schema.json.cmd does not exist
 [2] $(cmd_$1) is empty because cmd_chkdt is not defined

To address [1], use cmd_and_cmdsave instead of cmd.

To address [2], rename rule_chkdt to rule_mk_schema so that the stem
parts of cmd_* and rule_* match, like commit 7a0496056064 ("kbuild:
fix DT binding schema rule to detect command line changes").

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---

Another possibility might be to split out yamllint and chk_bindings
as standalone build rules instead of running them as a side-effect
of the schema build. (but it it up to Rob's preference)


 Documentation/devicetree/bindings/Makefile | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/Documentation/devicetree/bindings/Makefile b/Documentation/devicetree/bindings/Makefile
index 1eaccf135b30..bb40205689ea 100644
--- a/Documentation/devicetree/bindings/Makefile
+++ b/Documentation/devicetree/bindings/Makefile
@@ -46,10 +46,10 @@ quiet_cmd_mk_schema = SCHEMA  $@
                       $(DT_MK_SCHEMA) -j $(DT_MK_SCHEMA_FLAGS) @$$f > $@ ; \
 		      rm -f $$f
 
-define rule_chkdt
+define rule_mk_schema
 	$(if $(DT_SCHEMA_LINT),$(call cmd,yamllint),)
 	$(call cmd,chk_bindings)
-	$(call cmd,mk_schema)
+	$(call cmd_and_savecmd,mk_schema)
 endef
 
 DT_DOCS = $(patsubst $(srctree)/%,%,$(shell $(find_all_cmd)))
@@ -65,7 +65,7 @@ override DTC_FLAGS := \
 override DT_CHECKER_FLAGS ?=
 
 $(obj)/processed-schema.json: $(DT_DOCS) $(src)/.yamllint check_dtschema_version FORCE
-	$(call if_changed_rule,chkdt)
+	$(call if_changed_rule,mk_schema)
 
 always-y += processed-schema.json
 always-$(CHECK_DT_BINDING) += $(patsubst $(srctree)/$(src)/%.yaml,%.example.dts, $(CHK_DT_DOCS))
-- 
2.34.1