diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index d7e7e3d12bf1..dc25f36df720 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -3183,7 +3183,7 @@ sub process {
 				$compat2 =~ s/\,[a-zA-Z0-9]*\-/\,<\.\*>\-/;
 				my $compat3 = $compat;
 				$compat3 =~ s/\,([a-z]*)[0-9]*\-/\,$1<\.\*>\-/;
-				`grep -Erq "$compat|$compat2|$compat3" $dt_path`;
+				`grep -ERq "$compat|$compat2|$compat3" $dt_path`;
 				if ( $? >> 8 ) {
 					WARN("UNDOCUMENTED_DT_STRING",
 					     "DT compatible string \"$compat\" appears un-documented -- check $dt_path\n" . $herecurr);