diff --git a/src/ec/google/chromeec/ec_acpi.c b/src/ec/google/chromeec/ec_acpi.c
index 8a76805..b768316 100644
--- a/src/ec/google/chromeec/ec_acpi.c
+++ b/src/ec/google/chromeec/ec_acpi.c
@@ -144,7 +144,8 @@
 static void fill_ssdt_typec_device(const struct device *dev)
 {
 	int rv;
-	int i, num_ports;
+	int i;
+	unsigned int num_ports;
 	struct device *usb2_port;
 	struct device *usb3_port;
 	struct device *usb4_port;