diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c
index 18d13248d9bad6d36221bca3e163d66228d69144..f80904145fd4e3f5faeaa6a8440f7f5596115fde 100644
--- a/drivers/tty/serial/omap-serial.c
+++ b/drivers/tty/serial/omap-serial.c
@@ -740,8 +740,7 @@ serial_omap_set_termios(struct uart_port *port, struct ktermios *termios,
 	quot = serial_omap_get_divisor(port, baud);
 
 	/* calculate wakeup latency constraint */
-	up->calc_latency = (1000000 * up->port.fifosize) /
-				(1000 * baud / 8);
+	up->calc_latency = (USEC_PER_SEC * up->port.fifosize) / (baud / 8);
 	up->latency = up->calc_latency;
 	schedule_work(&up->qos_work);