diff --git a/drivers/usb/gadget/function/f_cdev.c b/drivers/usb/gadget/function/f_cdev.c
index 31ec75fed944..767b107216a0 100644
--- a/drivers/usb/gadget/function/f_cdev.c
+++ b/drivers/usb/gadget/function/f_cdev.c
@@ -1382,6 +1382,9 @@ static int f_cdev_tiocmget(struct f_cdev *port)
 
 	if (cser->serial_state & TIOCM_DSR)
 		result |= TIOCM_DSR;
+
+	if (cser->serial_state & TIOCM_CTS)
+		result |= TIOCM_CTS;
 	return result;
 }
 
@@ -1428,6 +1431,18 @@ static int f_cdev_tiocmset(struct f_cdev *port,
 	if (clear & TIOCM_DSR)
 		cser->serial_state &= ~TIOCM_DSR;
 
+	if (set & TIOCM_CTS) {
+		if (cser->send_break) {
+			cser->serial_state |= TIOCM_CTS;
+			status = cser->send_break(cser, 0);
+		}
+	}
+	if (clear & TIOCM_CTS) {
+		if (cser->send_break) {
+			cser->serial_state &= ~TIOCM_CTS;
+			status = cser->send_break(cser, 1);
+		}
+	}
 	return status;
 }
 
@@ -1556,8 +1571,10 @@ int usb_cser_connect(struct f_cdev *port)
 
 void usb_cser_disconnect(struct f_cdev *port)
 {
+	struct cserial *cser;
 	unsigned long flags;
 
+	cser = &port->port_usb;
 	usb_cser_stop_io(port);
 
 	/* lower DTR to modem */
@@ -1565,6 +1582,7 @@ void usb_cser_disconnect(struct f_cdev *port)
 
 	spin_lock_irqsave(&port->port_lock, flags);
 	port->is_connected = false;
+	cser->notify_modem = NULL;
 	port->nbytes_from_host = port->nbytes_to_host = 0;
 	port->nbytes_to_port_bridge = 0;
 	spin_unlock_irqrestore(&port->port_lock, flags);