2015-11-07 15:29 GMT+03:00 Peter Hurley [off-list ref]:

Hi Matwey,

On 11/07/2015 05:09 AM, Matwey V. Kornilov wrote:

quoted

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 <redacted>
---
 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;

To setup a default 8250 port function,
1. define the default 8250 port function in 8250/8250_port.c
2. add the port function to the dispatch table (serial8250_pops)

rs485_config is not a member of struct uart_ops, should I add it there?

3. add a test for 8250 sub-driver override in serial8250_register_8250_port()
   Eg.,

                if (up->port.rs485_config)
                        uart->port.rs485_config = up->port.rs485_config;

Regards,
Peter Hurley

quoted

              /* Take tx_loadsz from fifosize if it wasn't set separately */
              if (uart->port.fifosize && !uart->tx_loadsz)
                      uart->tx_loadsz = uart->port.fifosize;

-- 
With best regards,
Matwey V. Kornilov.
Sternberg Astronomical Institute, Lomonosov Moscow State University, Russia
119991, Moscow, Universitetsky pr-k 13, +7 (495) 9392382