diff --git a/drivers/staging/greybus/es1.c b/drivers/staging/greybus/es1.c
index f049d655b82e..2b4bb075b9e6 100644
--- a/drivers/staging/greybus/es1.c
+++ b/drivers/staging/greybus/es1.c
@@ -556,7 +556,7 @@ static int ap_probe(struct usb_interface *interface,
 	int i;
 
 	/* We need to fit a CPort ID in one byte of a message header */
-	BUILD_BUG_ON(CPORT_ID_MAX > U8_MAX);
+	BUILD_BUG_ON(CPORT_COUNT > U8_MAX + 1);
 
 	udev = usb_get_dev(interface_to_usbdev(interface));