serial: mxs-auart: enable PPS support

Enables PPS support in mxs-auart serial driver to make PPS API working.
Signed-off-by: NJanusz Uzycki <j.uzycki@elproma.com.pl>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/mxs-auart.c

@@ -784,6 +784,16 @@ static void mxs_auart_settermios(struct uart_port *u,
 		mxs_auart_disable_ms(u);
 }
 
+static void mxs_auart_set_ldisc(struct uart_port *port, int new)
+{
+	if (new == N_PPS) {
+		port->flags |= UPF_HARDPPS_CD;
+		mxs_auart_enable_ms(port);
+	} else {
+		port->flags &= ~UPF_HARDPPS_CD;
+	}
+}
+
 static irqreturn_t mxs_auart_irq_handle(int irq, void *context)
 {
 	u32 istat;
@@ -949,6 +959,7 @@ static struct uart_ops mxs_auart_ops = {
 	.startup	= mxs_auart_startup,
 	.shutdown       = mxs_auart_shutdown,
 	.set_termios    = mxs_auart_settermios,
+	.set_ldisc      = mxs_auart_set_ldisc,
 	.type	   	= mxs_auart_type,
 	.release_port   = mxs_auart_release_port,
 	.request_port   = mxs_auart_request_port,