serial: stm32: Fill in rs485_supported

Add information on supported serial_rs485 features.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220606100433.13793-22-ilpo.jarvinen@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/stm32-usart.c

@@ -1375,6 +1375,13 @@ static void stm32_usart_deinit_port(struct stm32_port *stm32port)
 	clk_disable_unprepare(stm32port->clk);
 }
 
+static const struct serial_rs485 stm32_rs485_supported = {
+	.flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | SER_RS485_RTS_AFTER_SEND |
+		 SER_RS485_RX_DURING_TX,
+	.delay_rts_before_send = 1,
+	.delay_rts_after_send = 1,
+};
+
 static int stm32_usart_init_port(struct stm32_port *stm32port,
 				 struct platform_device *pdev)
 {
@@ -1394,6 +1401,7 @@ static int stm32_usart_init_port(struct stm32_port *stm32port,
 	port->has_sysrq = IS_ENABLED(CONFIG_SERIAL_STM32_CONSOLE);
 	port->irq = irq;
 	port->rs485_config = stm32_usart_config_rs485;
+	port->rs485_supported = &stm32_rs485_supported;
 
 	ret = stm32_usart_init_rs485(port, pdev);
 	if (ret)