diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index e1179e74a2b89d..3b1aaa93d750e2 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -1023,10 +1023,10 @@ static int scif_set_rtrg(struct uart_port *port, int rx_trig)
 {
 	unsigned int bits;
 
+	if (rx_trig >= port->fifosize)
+		rx_trig = port->fifosize - 1;
 	if (rx_trig < 1)
 		rx_trig = 1;
-	if (rx_trig >= port->fifosize)
-		rx_trig = port->fifosize;
 
 	/* HSCIF can be set to an arbitrary level. */
 	if (sci_getreg(port, HSRTRGR)->size) {