[PATCH 1/2] serial: 8250: Fix runtime PM for start_tx() for RS485

[Tony Lindgren <tony@atomide.com>]

The early return from serial8250_start_tx() added by commit e490c9144cfa
("tty: Add software emulated RS485 support for 8250") failed to call
serial8250_rpm_put_tx() that normally gets called on __stop_tx().

Likely this is a harmless issue as the RS485 using folks probably are not
using runtime PM for the serial ports.

Fixes: e490c9144cfa ("tty: Add software emulated RS485 support for 8250")
Cc: Matwey V. Kornilov <matwey@sai.msu.ru>
Cc: Steffen Trumtrar <s.trumtrar@pengutronix.de>
Cc: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Tony Lindgren <tony@atomide.com>
---
 drivers/tty/serial/8250/8250_port.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -1681,8 +1681,10 @@ static void serial8250_start_tx(struct uart_port *port)
 		return;
 
 	if (em485 &&
-	    em485->active_timer == &em485->start_tx_timer)
+	    em485->active_timer == &em485->start_tx_timer) {
+		serial8250_rpm_put_tx(up);
 		return;
+	}
 
 	if (em485)
 		start_tx_rs485(port);
-- 
2.35.1