Duplicated unit address is a normal case, as long as no more than one
node using that address is enabled. Having duplicated addresses is
already allowed by '-Wno-unique_unit_address' in DTC_FLAGS. But two
simultaneously enabled nodes sharing the same address is usually
incorrect. Add '-Wunique_unit_address_if_enabled' flag to report
warnings for such case when doing "make dtbs_check".

Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
Reported-by: Rob Herring <robh@kernel.org>
Suggested-by: Rob Herring <robh@kernel.org>
---
NOTE: After applying this patch, a lot of warnings appear on "make
dtbs_check". I'm not completely sure if it's ok, so feel free to Nack.

 scripts/Makefile.lib | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index ce6142238835..2f00c996d2e3 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib

@@ -315,7 +315,8 @@ DTC_FLAGS += -Wno-unit_address_vs_reg \
 	-Wno-alias_paths \
 	-Wno-graph_child_address \
 	-Wno-simple_bus_reg \
-	-Wno-unique_unit_address
+	-Wno-unique_unit_address \
+	-Wunique_unit_address_if_enabled
 endif
 
 ifneq ($(findstring 2,$(KBUILD_EXTRA_WARN)),)

-- 
2.30.2