Kbuild: Use dtc's -d (dependency) option

This hooks dtc into Kbuild's dependency system.

Thus, for example, "make dtbs" will rebuild tegra-harmony.dtb if only
tegra20.dtsi has changed yet tegra-harmony.dts has not. The previous
lack of this feature recently caused me to have very confusing "git
bisect" results.

For ARM, it's obvious what to add to $(targets). I'm not familiar enough
with other architectures to know what to add there. Powerpc appears to
already add various .dtb files into $(targets), but the other archs may
need something added to $(targets) to work.

Signed-off-by: Stephen Warren <[email protected]>
Acked-by: Shawn Guo <[email protected]>
Acked-by: Mark Salter <[email protected]>

diff --git a/arch/c6x/boot/Makefile b/arch/c6x/boot/Makefile
index ecca820e60419fd70341ba7c4a544723c7963529..6891257d514c39c540978508a9088343f9b6e740 100644 (file)
--- a/arch/c6x/boot/Makefile
+++ b/arch/c6x/boot/Makefile
@@ -13,7 +13,7 @@ obj-y += linked_dtb.o
 endif
 
 $(obj)/%.dtb: $(src)/dts/%.dts FORCE
-       $(call cmd,dtc)
+       $(call if_changed_dep,dtc)
 
 quiet_cmd_cp = CP      $< $@$2
        cmd_cp = cat $< >$@$2 || (rm -f $@ && echo false)