When 8250 driver doesn't have its own hardware RS485 support and doesn't
want to override rs485_config callback, then default
serial8250_rs485_config is used. It just stores supplied by user-space
config.

Signed-off-by: Matwey V. Kornilov <mat...@sai.msu.ru>
---
 drivers/tty/serial/8250/8250_core.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/tty/serial/8250/8250_core.c 
b/drivers/tty/serial/8250/8250_core.c
index 3912646..8f292da 100644
--- a/drivers/tty/serial/8250/8250_core.c
+++ b/drivers/tty/serial/8250/8250_core.c
@@ -395,6 +395,12 @@ static void serial8250_release_rsa_resource(struct 
uart_8250_port *up)
        }
 }
 #endif
+static int serial8250_rs485_config(struct uart_port *port,
+                               struct serial_rs485 *rs485)
+{
+       port->rs485 = *rs485;
+       return 0;
+}
 
 static const struct uart_ops *base_ops;
 static struct uart_ops univ8250_port_ops;
@@ -990,6 +996,10 @@ int serial8250_register_8250_port(struct uart_8250_port 
*up)
                uart->port.rs485        = up->port.rs485;
                uart->dma               = up->dma;
 
+               /* Use software RS485 support when hardware one is not 
available */
+               if (!(uart->capabilities & UART_CAP_HW485) && 
!uart->port.rs485_config)
+                       uart->port.rs485_config = serial8250_rs485_config;
+
                /* Take tx_loadsz from fifosize if it wasn't set separately */
                if (uart->port.fifosize && !uart->tx_loadsz)
                        uart->tx_loadsz = uart->port.fifosize;
-- 
2.6.2

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