--- a/vizzini.c	2013-01-22 15:37:32.345592809 -0600
+++ b/vizzini.c	2013-01-29 14:27:04.550051817 -0600
@@ -186,6 +186,7 @@
 #ifdef VIZZINI_IWA
         int           iwa;
 #endif
+        struct serial_rs485 rs485;
 };
 
 
@@ -428,7 +429,41 @@
 	return -EINVAL;
 }
 
+static int vizzini_set_rs485(struct usb_serial_port *port, struct serial_rs485 *rs485conf)
+{
+	struct vizzini_port_private *portdata = usb_get_serial_port_data(port);
+	int 		block 	= portdata->block;
+	int result = 0;
+	unsigned int gpio_mode, flow = 0;
+
+	portdata->rs485 = *rs485conf;
+
+	if (portdata->rs485.flags & SER_RS485_ENABLED) {
+		dev_info(&port->dev, "Enabling RS485");
+
+		/* enable auto tranceiver enable on transmit, TX active high */
+		gpio_mode = UART_GPIO_MODE_SEL_XCVR_EN_ACT | UART_GPIO_MODE_XCVR_EN_POL;
+
+		result = vizzini_set_reg(port, block, UART_GPIO_MODE, gpio_mode);
 
+		if (result < 0)
+			dev_err(&port->dev, "Error setting auto trans enable");
+
+		/* half duplex rs485 */
+		flow = UART_FLOW_HALF_DUPLEX;
+		result = vizzini_set_reg(port, block, UART_FLOW, flow);
+
+		if (result < 0)
+			dev_err(&port->dev, "Error setting half duplex");
+	}
+	else {
+		dev_info(&port->dev, "Disabling RS485 - flow control off");
+        	vizzini_set_reg(port, block, UART_GPIO_MODE, UART_GPIO_MODE_SEL_GPIO);
+        	vizzini_set_reg(port, block, UART_FLOW, UART_FLOW_MODE_NONE);
+	}
+	
+	return 0;
+}
 
 static void vizzini_set_termios(struct tty_struct *tty_param,
                                 struct usb_serial_port *port,
@@ -604,6 +639,7 @@
         char                    *data;
         int                      result;
         struct serial_struct     ss;
+        struct serial_rs485      rs485conf;
 
         if (debug) dev_dbg(&port->dev, "%s %08x\n", __func__, cmd);
 
@@ -636,6 +672,36 @@
 /*      mutex_unlock(&config_mutex); */
                 break;
 
+        case TIOCGRS485:
+                if (!arg) {
+                        dev_err(&port->dev, "%s - TIOCGRS485 arg invalid\n", __func__);
+                        return -EFAULT;
+		}
+                if (copy_to_user((struct serial_rs485 *) arg,
+                        &(portdata->rs485),
+                        sizeof(struct serial_rs485))) {
+                        dev_err(&port->dev, "%s - TIOCGRS485 copy_to_user fail\n", __func__);
+                        return -EFAULT;
+                }
+                break;
+
+        case TIOCSRS485:
+        	dev_dbg(&port->dev, "%s TIOCSRS485\n", __func__);
+                if (!arg) {
+                        return -EFAULT;
+                        dev_err(&port->dev, "%s - TIOCSRS485 arg invalid\n", __func__);
+		}
+                if (copy_from_user(&rs485conf, (struct serial_rs485 *) arg,
+                        sizeof(rs485conf))) {
+                        dev_err(&port->dev, "%s - TIOCSRS485 copy_from_user fail\n", __func__);
+                        return -EFAULT;
+                }
+
+                vizzini_disable(port);
+                vizzini_set_rs485(port, &rs485conf);
+                vizzini_enable(port);
+                break;
+
         case VZIOC_GET_REG:
                 if (get_user(block, (int __user *)arg))
                         return -EFAULT;