serial: sc16is7xx: Read modem line state at startup

This patch sets the driver modem line state to the actual line state
at driver startup.

See: https://github.com/raspberrypi/linux/issues/5501

Signed-off-by: Earl Schmidt <schmidt.earl.f@gmail.com>
Signed-off-by: Phil Elwell <phil@raspberrypi.com>

diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c
index 7690c8536cc06e4febabc4ce88d0635b3f018a3a..eea6622122afeff394315e697c460c4b0b06da44 100644 (file)
--- a/drivers/tty/serial/sc16is7xx.c
+++ b/drivers/tty/serial/sc16is7xx.c
@@ -1193,6 +1193,9 @@ static int sc16is7xx_startup(struct uart_port *port)
              SC16IS7XX_IER_MSI_BIT;
        sc16is7xx_port_write(port, SC16IS7XX_IER_REG, val);
 
+       /* Initialize the Modem Control signals to current status */
+       one->old_mctrl = sc16is7xx_get_hwmctrl(port);
+
        /* Enable modem status polling */
        uart_port_lock_irqsave(port, &flags);
        sc16is7xx_enable_ms(port);