diff --git a/drivers/usb/serial/ch341.c b/drivers/usb/serial/ch341.c
index df582fe855f0..d3f420f3a083 100644
--- a/drivers/usb/serial/ch341.c
+++ b/drivers/usb/serial/ch341.c
@@ -642,9 +642,13 @@ static int ch341_tiocmget(struct tty_struct *tty)
 static int ch341_reset_resume(struct usb_serial *serial)
 {
 	struct usb_serial_port *port = serial->port[0];
-	struct ch341_private *priv = usb_get_serial_port_data(port);
+	struct ch341_private *priv;
 	int ret;
 
+	priv = usb_get_serial_port_data(port);
+	if (!priv)
+		return 0;
+
 	/* reconfigure ch341 serial port after bus-reset */
 	ch341_configure(serial->dev, priv);
 
diff --git a/drivers/usb/serial/io_edgeport.c b/drivers/usb/serial/io_edgeport.c
index 9690a5f4b9d6..5737add6a2a4 100644
--- a/drivers/usb/serial/io_edgeport.c
+++ b/drivers/usb/serial/io_edgeport.c
@@ -716,7 +716,7 @@ static void edge_interrupt_callback(struct urb *urb)
 			if (txCredits) {
 				port = edge_serial->serial->port[portNumber];
 				edge_port = usb_get_serial_port_data(port);
-				if (edge_port->open) {
+				if (edge_port && edge_port->open) {
 					spin_lock_irqsave(&edge_port->ep_lock,
 							  flags);
 					edge_port->txCredits += txCredits;
@@ -1725,7 +1725,8 @@ static void edge_break(struct tty_struct *tty, int break_state)
 static void process_rcvd_data(struct edgeport_serial *edge_serial,
 				unsigned char *buffer, __u16 bufferLength)
 {
-	struct device *dev = &edge_serial->serial->dev->dev;
+	struct usb_serial *serial = edge_serial->serial;
+	struct device *dev = &serial->dev->dev;
 	struct usb_serial_port *port;
 	struct edgeport_port *edge_port;
 	__u16 lastBufferLength;
@@ -1821,11 +1822,10 @@ static void process_rcvd_data(struct edgeport_serial *edge_serial,
 
 			/* spit this data back into the tty driver if this
 			   port is open */
-			if (rxLen) {
-				port = edge_serial->serial->port[
-							edge_serial->rxPort];
+			if (rxLen && edge_serial->rxPort < serial->num_ports) {
+				port = serial->port[edge_serial->rxPort];
 				edge_port = usb_get_serial_port_data(port);
-				if (edge_port->open) {
+				if (edge_port && edge_port->open) {
 					dev_dbg(dev, "%s - Sending %d bytes to TTY for port %d\n",
 						__func__, rxLen,
 						edge_serial->rxPort);
@@ -1833,8 +1833,8 @@ static void process_rcvd_data(struct edgeport_serial *edge_serial,
 							rxLen);
 					edge_port->port->icount.rx += rxLen;
 				}
-				buffer += rxLen;
 			}
+			buffer += rxLen;
 			break;
 
 		case EXPECT_HDR3:	/* Expect 3rd byte of status header */
@@ -1869,6 +1869,8 @@ static void process_rcvd_status(struct edgeport_serial *edge_serial,
 	__u8 code = edge_serial->rxStatusCode;
 
 	/* switch the port pointer to the one being currently talked about */
+	if (edge_serial->rxPort >= edge_serial->serial->num_ports)
+		return;
 	port = edge_serial->serial->port[edge_serial->rxPort];
 	edge_port = usb_get_serial_port_data(port);
 	if (edge_port == NULL) {
diff --git a/drivers/usb/serial/keyspan.c b/drivers/usb/serial/keyspan.c
index e66a59ef43a1..aa3dbce22cfb 100644
--- a/drivers/usb/serial/keyspan.c
+++ b/drivers/usb/serial/keyspan.c
@@ -1058,6 +1058,8 @@ static void	usa49_glocont_callback(struct urb *urb)
 	for (i = 0; i < serial->num_ports; ++i) {
 		port = serial->port[i];
 		p_priv = usb_get_serial_port_data(port);
+		if (!p_priv)
+			continue;
 
 		if (p_priv->resend_cont) {
 			dev_dbg(&port->dev, "%s - sending setup\n", __func__);
@@ -1459,6 +1461,8 @@ static void usa67_glocont_callback(struct urb *urb)
 	for (i = 0; i < serial->num_ports; ++i) {
 		port = serial->port[i];
 		p_priv = usb_get_serial_port_data(port);
+		if (!p_priv)
+			continue;
 
 		if (p_priv->resend_cont) {
 			dev_dbg(&port->dev, "%s - sending setup\n", __func__);
diff --git a/drivers/usb/serial/opticon.c b/drivers/usb/serial/opticon.c
index cb7aac9cd9e7..ed2b4e6dca38 100644
--- a/drivers/usb/serial/opticon.c
+++ b/drivers/usb/serial/opticon.c
@@ -113,7 +113,7 @@ static int send_control_msg(struct usb_serial_port *port, u8 requesttype,
 	retval = usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
 				requesttype,
 				USB_DIR_OUT|USB_TYPE_VENDOR|USB_RECIP_INTERFACE,
-				0, 0, buffer, 1, 0);
+				0, 0, buffer, 1, USB_CTRL_SET_TIMEOUT);
 	kfree(buffer);
 
 	if (retval < 0)
diff --git a/drivers/usb/serial/option.c b/drivers/usb/serial/option.c
index 2d919d0e6e45..084cc2fff3ae 100644
--- a/drivers/usb/serial/option.c
+++ b/drivers/usb/serial/option.c
@@ -248,6 +248,7 @@ static void option_instat_callback(struct urb *urb);
 #define QUECTEL_PRODUCT_BG96			0x0296
 #define QUECTEL_PRODUCT_EP06			0x0306
 #define QUECTEL_PRODUCT_EM12			0x0512
+#define QUECTEL_PRODUCT_RM500Q			0x0800
 
 #define CMOTECH_VENDOR_ID			0x16d8
 #define CMOTECH_PRODUCT_6001			0x6001
@@ -1104,6 +1105,11 @@ static const struct usb_device_id option_ids[] = {
 	{ USB_DEVICE_AND_INTERFACE_INFO(QUECTEL_VENDOR_ID, QUECTEL_PRODUCT_EM12, 0xff, 0xff, 0xff),
 	  .driver_info = RSVD(1) | RSVD(2) | RSVD(3) | RSVD(4) | NUMEP2 },
 	{ USB_DEVICE_AND_INTERFACE_INFO(QUECTEL_VENDOR_ID, QUECTEL_PRODUCT_EM12, 0xff, 0, 0) },
+	{ USB_DEVICE_AND_INTERFACE_INFO(QUECTEL_VENDOR_ID, QUECTEL_PRODUCT_RM500Q, 0xff, 0xff, 0x30) },
+	{ USB_DEVICE_AND_INTERFACE_INFO(QUECTEL_VENDOR_ID, QUECTEL_PRODUCT_RM500Q, 0xff, 0, 0) },
+	{ USB_DEVICE_AND_INTERFACE_INFO(QUECTEL_VENDOR_ID, QUECTEL_PRODUCT_RM500Q, 0xff, 0xff, 0x10),
+	  .driver_info = ZLP },
+
 	{ USB_DEVICE(CMOTECH_VENDOR_ID, CMOTECH_PRODUCT_6001) },
 	{ USB_DEVICE(CMOTECH_VENDOR_ID, CMOTECH_PRODUCT_CMU_300) },
 	{ USB_DEVICE(CMOTECH_VENDOR_ID, CMOTECH_PRODUCT_6003),
diff --git a/drivers/usb/serial/quatech2.c b/drivers/usb/serial/quatech2.c
index a62981ca7a73..f93b81a297d6 100644
--- a/drivers/usb/serial/quatech2.c
+++ b/drivers/usb/serial/quatech2.c
@@ -841,7 +841,10 @@ static void qt2_update_msr(struct usb_serial_port *port, unsigned char *ch)
 	u8 newMSR = (u8) *ch;
 	unsigned long flags;
 
+	/* May be called from qt2_process_read_urb() for an unbound port. */
 	port_priv = usb_get_serial_port_data(port);
+	if (!port_priv)
+		return;
 
 	spin_lock_irqsave(&port_priv->lock, flags);
 	port_priv->shadowMSR = newMSR;
@@ -869,7 +872,10 @@ static void qt2_update_lsr(struct usb_serial_port *port, unsigned char *ch)
 	unsigned long flags;
 	u8 newLSR = (u8) *ch;
 
+	/* May be called from qt2_process_read_urb() for an unbound port. */
 	port_priv = usb_get_serial_port_data(port);
+	if (!port_priv)
+		return;
 
 	if (newLSR & UART_LSR_BI)
 		newLSR &= (u8) (UART_LSR_OE | UART_LSR_BI);
diff --git a/drivers/usb/serial/usb-serial-simple.c b/drivers/usb/serial/usb-serial-simple.c
index edbbb13d6de6..bd23a7cb1be2 100644
--- a/drivers/usb/serial/usb-serial-simple.c
+++ b/drivers/usb/serial/usb-serial-simple.c
@@ -86,6 +86,8 @@ DEVICE(moto_modem, MOTO_IDS);
 #define MOTOROLA_TETRA_IDS()			\
 	{ USB_DEVICE(0x0cad, 0x9011) },	/* Motorola Solutions TETRA PEI */ \
 	{ USB_DEVICE(0x0cad, 0x9012) },	/* MTP6550 */ \
+	{ USB_DEVICE(0x0cad, 0x9013) },	/* MTP3xxx */ \
+	{ USB_DEVICE(0x0cad, 0x9015) },	/* MTP85xx */ \
 	{ USB_DEVICE(0x0cad, 0x9016) }	/* TPG2200 */
 DEVICE(motorola_tetra, MOTOROLA_TETRA_IDS);
 
diff --git a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c
index 8f066bb55d7d..dc7a65b9ec98 100644
--- a/drivers/usb/serial/usb-serial.c
+++ b/drivers/usb/serial/usb-serial.c
@@ -1317,6 +1317,9 @@ static int usb_serial_register(struct usb_serial_driver *driver)
 		return -EINVAL;
 	}
 
+	/* Prevent individual ports from being unbound. */
+	driver->driver.suppress_bind_attrs = true;
+
 	usb_serial_operations_init(driver);
 
 	/* Add this device to our list of devices */