serial: 8250_exar: 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/20220606100433.13793-8-ilpo.jarvinen@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/8250/8250_exar.c

@@ -113,6 +113,7 @@ struct exar8250;
 
 struct exar8250_platform {
 	int (*rs485_config)(struct uart_port *, struct serial_rs485 *);
+	const struct serial_rs485 *rs485_supported;
 	int (*register_gpio)(struct pci_dev *, struct uart_8250_port *);
 	void (*unregister_gpio)(struct uart_8250_port *);
 };
@@ -431,10 +432,15 @@ static int generic_rs485_config(struct uart_port *port,
 	return 0;
 }
 
+static const struct serial_rs485 generic_rs485_supported = {
+	.flags = SER_RS485_ENABLED,
+};
+
 static const struct exar8250_platform exar8250_default_platform = {
 	.register_gpio = xr17v35x_register_gpio,
 	.unregister_gpio = xr17v35x_unregister_gpio,
 	.rs485_config = generic_rs485_config,
+	.rs485_supported = &generic_rs485_supported,
 };
 
 static int iot2040_rs485_config(struct uart_port *port,
@@ -470,6 +476,10 @@ static int iot2040_rs485_config(struct uart_port *port,
 	return generic_rs485_config(port, rs485);
 }
 
+static const struct serial_rs485 iot2040_rs485_supported = {
+	.flags = SER_RS485_ENABLED | SER_RS485_RX_DURING_TX | SER_RS485_TERMINATE_BUS,
+};
+
 static const struct property_entry iot2040_gpio_properties[] = {
 	PROPERTY_ENTRY_U32("exar,first-pin", 10),
 	PROPERTY_ENTRY_U32("ngpios", 1),
@@ -498,6 +508,7 @@ static int iot2040_register_gpio(struct pci_dev *pcidev,
 
 static const struct exar8250_platform iot2040_platform = {
 	.rs485_config = iot2040_rs485_config,
+	.rs485_supported = &iot2040_rs485_supported,
 	.register_gpio = iot2040_register_gpio,
 	.unregister_gpio = xr17v35x_unregister_gpio,
 };
@@ -540,6 +551,7 @@ pci_xr17v35x_setup(struct exar8250 *priv, struct pci_dev *pcidev,
 
 	port->port.uartclk = baud * 16;
 	port->port.rs485_config = platform->rs485_config;
+	port->port.rs485_supported = platform->rs485_supported;
 
 	/*
 	 * Setup the UART clock for the devices on expansion slot to