Use software emulated RS485 direction control to provide RS485 API existed in
omap_serial driver. Note that 8250_omap issues interrupt on shift register
empty which is single prerequesite for using software emulated RS485.
Signed-off-by: Matwey V. Kornilov <matwey@xxxxxxxxxx>
---
drivers/tty/serial/8250/8250_omap.c | 25 +++++++++++++++++++++++++
1 file changed, 25 insertions(+)
diff --git a/drivers/tty/serial/8250/8250_omap.c b/drivers/tty/serial/8250/8250_omap.c
index a2c0734..31f7905 100644
--- a/drivers/tty/serial/8250/8250_omap.c
+++ b/drivers/tty/serial/8250/8250_omap.c
@@ -697,6 +697,30 @@ static void omap_8250_throttle(struct uart_port *port)
pm_runtime_put_autosuspend(port->dev);
}
+static int omap_8250_rs485_config(struct uart_port *port, struct serial_rs485 *rs485)
+{
+ struct uart_8250_port *up = up_to_u8250p(port);
+
+ /* Clamp the delays to [0, 100ms] */
+ rs485->delay_rts_before_send = min(rs485->delay_rts_before_send, 100U);
+ rs485->delay_rts_after_send = min(rs485->delay_rts_after_send, 100U);
+
+ port->rs485 = *rs485;
+
+ /* Both serial8250_em485_* functions are idempotent */
+ if (rs485->flags & SER_RS485_ENABLED) {
+ int ret = serial8250_em485_init(up);
+ if (ret) {
+ rs485->flags &= ~SER_RS485_ENABLED;
+ port->rs485.flags &= ~SER_RS485_ENABLED;
+ }
+ return ret;
+ } else
+ serial8250_em485_destroy(up);
+
+ return 0;
+}
+
static void omap_8250_unthrottle(struct uart_port *port)
{
unsigned long flags;
@@ -1146,6 +1170,7 @@ static int omap8250_probe(struct platform_device *pdev)
up.port.shutdown = omap_8250_shutdown;
up.port.throttle = omap_8250_throttle;
up.port.unthrottle = omap_8250_unthrottle;
+ up.port.rs485_config = omap_8250_rs485_config;
if (pdev->dev.of_node) {
const struct of_device_id *id;
--
2.7.0
--
To unsubscribe from this list: send the line "unsubscribe linux-serial" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
