diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c
index 30b7890645ac..c3348d5af922 100644
--- a/drivers/tty/serial/8250/8250_core.c
+++ b/drivers/tty/serial/8250/8250_core.c
@@ -300,10 +300,9 @@ static void serial8250_backup_timeout(struct timer_list *t)
 		jiffies + uart_poll_timeout(&up->port) + HZ / 5);
 }
 
-static int univ8250_setup_irq(struct uart_8250_port *up)
+static void univ8250_setup_timer(struct uart_8250_port *up)
 {
 	struct uart_port *port = &up->port;
-	int retval = 0;
 
 	/*
 	 * The above check will only give an accurate result the first time
@@ -324,10 +323,16 @@ static int univ8250_setup_irq(struct uart_8250_port *up)
 	 */
 	if (!port->irq)
 		mod_timer(&up->timer, jiffies + uart_poll_timeout(port));
-	else
-		retval = serial_link_irq_chain(up);
+}
 
-	return retval;
+static int univ8250_setup_irq(struct uart_8250_port *up)
+{
+	struct uart_port *port = &up->port;
+
+	if (port->irq)
+		return serial_link_irq_chain(up);
+
+	return 0;
 }
 
 static void univ8250_release_irq(struct uart_8250_port *up)
@@ -383,6 +388,7 @@ static struct uart_ops univ8250_port_ops;
 static const struct uart_8250_ops univ8250_driver_ops = {
 	.setup_irq	= univ8250_setup_irq,
 	.release_irq	= univ8250_release_irq,
+	.setup_timer	= univ8250_setup_timer,
 };
 
 static struct uart_8250_port serial8250_ports[UART_NR];
diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index b07326b71834..ee457f5d504f 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -2280,6 +2280,10 @@ int serial8250_do_startup(struct uart_port *port)
 	if (port->irq && (up->port.flags & UPF_SHARE_IRQ))
 		up->port.irqflags |= IRQF_SHARED;
 
+	retval = up->ops->setup_irq(up);
+	if (retval)
+		goto out;
+
 	if (port->irq && !(up->port.flags & UPF_NO_THRE_TEST)) {
 		unsigned char iir1;
 
@@ -2322,9 +2326,7 @@ int serial8250_do_startup(struct uart_port *port)
 		}
 	}
 
-	retval = up->ops->setup_irq(up);
-	if (retval)
-		goto out;
+	up->ops->setup_timer(up);
 
 	/*
 	 * Now, initialize the UART
diff --git a/include/linux/serial_8250.h b/include/linux/serial_8250.h
index 5db211f43b29..68abc6bdd891 100644
--- a/include/linux/serial_8250.h
+++ b/include/linux/serial_8250.h
@@ -74,6 +74,7 @@ struct uart_8250_port;
 struct uart_8250_ops {
 	int		(*setup_irq)(struct uart_8250_port *);
 	void		(*release_irq)(struct uart_8250_port *);
+	void		(*setup_timer)(struct uart_8250_port *);
 };
 
 struct uart_8250_em485 {