diff --git a/tools/gpio/Makefile b/tools/gpio/Makefile
index 6ecdd1067826..1178d302757e 100644
--- a/tools/gpio/Makefile
+++ b/tools/gpio/Makefile
@@ -3,7 +3,11 @@ include ../scripts/Makefile.include
 
 bindir ?= /usr/bin
 
-ifeq ($(srctree),)
+# This will work when gpio is built in tools env. where srctree
+# isn't set and when invoked from selftests build, where srctree
+# is set to ".". building_out_of_srctree is undefined for in srctree
+# builds
+ifndef building_out_of_srctree
 srctree := $(patsubst %/,%,$(dir $(CURDIR)))
 srctree := $(patsubst %/,%,$(dir $(srctree)))
 endif