Currently the makefile is setup in such manner that even if
we build a DT file in a subdirectory under arch/arm/boot/dts,
it gets built based on the base boot/dts/Makefile rules.
This patch modifies the base makefile in such manner, that
it detects which makefile to use based on build target path.
This allows setting for example per-directory DTC_FLAGS and
using those for the subdir build. The dtbdir local variable
is setup to target to the build path.

Signed-off-by: Tero Kristo <redacted>
---
 arch/arm/Makefile | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/arm/Makefile b/arch/arm/Makefile
index ab555a0..b7c21e8 100644
--- a/arch/arm/Makefile
+++ b/arch/arm/Makefile

@@ -339,8 +339,10 @@ $(BOOT_TARGETS): vmlinux
 $(INSTALL_TARGETS):
 	$(Q)$(MAKE) $(build)=$(boot) MACHINE=$(MACHINE) $@
 
+%.dtb %.dtbo: dtbdir = $(patsubst %/,%,$(patsubst %./,%,$(boot)/dts/$(dir $@)))
+
 %.dtb %.dtbo: | scripts
-	$(Q)$(MAKE) $(build)=$(boot)/dts MACHINE=$(MACHINE) $(boot)/dts/$@
+	$(Q)$(MAKE) $(build)=$(dtbdir) MACHINE=$(MACHINE) $(boot)/dts/$@
 
 PHONY += dtbs dtbs_install
 

-- 
1.9.1

--
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