serial: of-serial: fetch line number from DT

The general agreed way to specify a fixed line number
for a serial console is to provide a "serial" alias
in the devicetree. Start parsing this property in
of_serial.

Signed-off-by: Lucas Stach <dev@lynxeye.de>
Acked-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 5 insertions, 0 deletions

diff --git a/drivers/tty/serial/of_serial.c b/drivers/tty/serial/of_serial.c
index fbb719c89a61..7ff61e24a195 100644
--- a/drivers/tty/serial/of_serial.c
+++ b/drivers/tty/serial/of_serial.c
@@ -102,6 +102,11 @@ static int of_platform_serial_setup(struct platform_device *ofdev,
         if (of_property_read_u32(np, "fifo-size", &prop) == 0)
                 port->fifosize = prop;
 
+        /* Check for a fixed line number */
+        ret = of_alias_get_id(np, "serial");
+        if (ret >= 0)
+                port->line = ret;
+
         port->irq = irq_of_parse_and_map(np, 0);
         port->iotype = UPIO_MEM;
         if (of_property_read_u32(np, "reg-io-width", &prop) == 0) {