Index: head/sys/conf/Makefile.arm
===================================================================
--- head/sys/conf/Makefile.arm
+++ head/sys/conf/Makefile.arm
@@ -32,6 +32,9 @@
 
 INCLUDES+= -I$S/contrib/libfdt -I$S/gnu/dts/include 
 
+LINUX_DTS_VERSION!=	       make -C $S/gnu/dts/ -V LINUX_DTS_VERSION
+CFLAGS += -DLINUX_DTS_VERSION=\"${LINUX_DTS_VERSION}\"
+
 .if !defined(DEBUG) && !defined(PROFLEVEL)
 STRIP_FLAGS = -S
 .endif
Index: head/sys/dts/freebsd-compatible.dts
===================================================================
--- head/sys/dts/freebsd-compatible.dts
+++ head/sys/dts/freebsd-compatible.dts
@@ -0,0 +1,3 @@
+/ {
+	freebsd,dts-version = LINUX_DTS_VERSION;
+};
Index: head/sys/gnu/dts/Makefile
===================================================================
--- head/sys/gnu/dts/Makefile
+++ head/sys/gnu/dts/Makefile
@@ -0,0 +1,3 @@
+# $FreeBSD$
+
+LINUX_DTS_VERSION=5.8
Index: head/sys/tools/fdt/make_dtb.sh
===================================================================
--- head/sys/tools/fdt/make_dtb.sh
+++ head/sys/tools/fdt/make_dtb.sh
@@ -20,9 +20,11 @@
 : "${ECHO:=echo}"
 : "${CPP:=cpp}"
 
+LINUX_DTS_VERSION=$(make -C $S/gnu/dts -V LINUX_DTS_VERSION)
+
 for d in ${dts}; do
     dtb="${dtb_path}/$(basename "$d" .dts).dtb"
     ${ECHO} "converting $d -> $dtb"
-    ${CPP} -P -x assembler-with-cpp -I "$S/gnu/dts/include" -I "$S/dts/${MACHINE}" -I "$S/gnu/dts/${MACHINE}" -I "$S/gnu/dts/" -include "$d" /dev/null |
+    ${CPP} -DLINUX_DTS_VERSION=\"${LINUX_DTS_VERSION}\" -P -x assembler-with-cpp -I "$S/gnu/dts/include" -I "$S/dts/${MACHINE}" -I "$S/gnu/dts/${MACHINE}" -I "$S/gnu/dts/" -include "$d" -include "$S/dts/freebsd-compatible.dts" /dev/null |
 	${DTC} -@ -O dtb -o "$dtb" -b 0 -p 1024 -i "$S/dts/${MACHINE}" -i "$S/gnu/dts/${MACHINE}" -i "$S/gnu/dts/"
 done