diff --git a/drivers/tty/serial/st-asc.c b/drivers/tty/serial/st-asc.c
index 7971997cdead..ce35e3a131b1 100644
--- a/drivers/tty/serial/st-asc.c
+++ b/drivers/tty/serial/st-asc.c
@@ -540,10 +540,14 @@ static void asc_set_termios(struct uart_port *port, struct ktermios *termios,
 	/* set character length */
 	if ((cflag & CSIZE) == CS7) {
 		ctrl_val |= ASC_CTL_MODE_7BIT_PAR;
+		cflag |= PARENB;
 	} else {
 		ctrl_val |= (cflag & PARENB) ?  ASC_CTL_MODE_8BIT_PAR :
 						ASC_CTL_MODE_8BIT;
+		cflag &= ~CSIZE;
+		cflag |= CS8;
 	}
+	termios->c_cflag = cflag;
 
 	/* set stop bit */
 	ctrl_val |= (cflag & CSTOPB) ? ASC_CTL_STOP_2BIT : ASC_CTL_STOP_1BIT;