kbuild: Allow using host dtc instead of kernel's copy

Development of dtc happens in its own upstream repository, but testing
dtc changes against the kernel tree is useful. Change dtc to a variable
that users can override.

Signed-off-by: Rob Herring <robh@kernel.org>
Cc: Michal Marek <mmarek@suse.com>
Cc: linux-kbuild@vger.kernel.org

diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 2edbcadb3d7f6daa047c68f78c32e6acb5508bfa..ad50d5859ac4f53fe1a0eafb5ea67504a29f72d4 100644 (file)
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -269,6 +269,7 @@ cmd_gzip = (cat $(filter-out FORCE,$^) | gzip -n -f -9 > $@) || \
 
 # DTC
 # ---------------------------------------------------------------------------
+DTC ?= $(objtree)/scripts/dtc/dtc
 
 # Generate an assembly file to wrap the output of the device tree compiler
 quiet_cmd_dt_S_dtb= DTB     $@
@@ -291,7 +292,7 @@ $(obj)/%.dtb.S: $(obj)/%.dtb
 quiet_cmd_dtc = DTC     $@
 cmd_dtc = mkdir -p $(dir ${dtc-tmp}) ; \
        $(CPP) $(dtc_cpp_flags) -x assembler-with-cpp -o $(dtc-tmp) $< ; \
-       $(objtree)/scripts/dtc/dtc -O dtb -o $@ -b 0 \
+       $(DTC) -O dtb -o $@ -b 0 \
                -i $(dir $<) $(DTC_FLAGS) \
                -d $(depfile).dtc.tmp $(dtc-tmp) ; \
        cat $(depfile).pre.tmp $(depfile).dtc.tmp > $(depfile)