serial: 8250_fintek: Fill in rs485_supported

Add information on supported serial_rs485 features.

Differentiate based on which port is in question.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220606100433.13793-9-ilpo.jarvinen@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/8250/8250_fintek.c

@@ -424,6 +424,17 @@ static int probe_setup_port(struct fintek_8250 *pdata,
 	return -ENODEV;
 }
 
+/* Only the first port supports delays */
+static const struct serial_rs485 fintek_8250_rs485_supported_port0 = {
+	.flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | SER_RS485_RTS_AFTER_SEND,
+	.delay_rts_before_send = 1,
+	.delay_rts_after_send = 1,
+};
+
+static const struct serial_rs485 fintek_8250_rs485_supported = {
+	.flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | SER_RS485_RTS_AFTER_SEND,
+};
+
 static void fintek_8250_set_rs485_handler(struct uart_8250_port *uart)
 {
 	struct fintek_8250 *pdata = uart->port.private_data;
@@ -435,6 +446,10 @@ static void fintek_8250_set_rs485_handler(struct uart_8250_port *uart)
 	case CHIP_ID_F81866:
 	case CHIP_ID_F81865:
 		uart->port.rs485_config = fintek_8250_rs485_config;
+		if (!pdata->index)
+			uart->port.rs485_supported = &fintek_8250_rs485_supported_port0;
+		else
+			uart->port.rs485_supported = &fintek_8250_rs485_supported;
 		break;
 
 	default: /* No RS485 Auto direction functional */