diff --git a/drivers/usb/gadget/f_serial.c b/drivers/usb/gadget/f_serial.c
index 91fdf790ed2..cf33a8d0fd5 100644
--- a/drivers/usb/gadget/f_serial.c
+++ b/drivers/usb/gadget/f_serial.c
@@ -131,8 +131,8 @@ static int gser_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
 	}
 	if (!gser->port.in->desc || !gser->port.out->desc) {
 		DBG(cdev, "activate generic ttyGS%d\n", gser->port_num);
-		if (!config_ep_by_speed(cdev->gadget, f, gser->port.in) ||
-		    !config_ep_by_speed(cdev->gadget, f, gser->port.out)) {
+		if (config_ep_by_speed(cdev->gadget, f, gser->port.in) ||
+		    config_ep_by_speed(cdev->gadget, f, gser->port.out)) {
 			gser->port.in->desc = NULL;
 			gser->port.out->desc = NULL;
 			return -EINVAL;