diff --git a/drivers/tty/serial/8250/8250_exar.c b/drivers/tty/serial/8250/8250_exar.c
index 5c2adf14049b..19de9f535c67 100644
--- a/drivers/tty/serial/8250/8250_exar.c
+++ b/drivers/tty/serial/8250/8250_exar.c
@@ -123,6 +123,7 @@ 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 *);
 };
 
@@ -423,9 +424,14 @@ 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,
 	.rs485_config = generic_rs485_config,
+	.rs485_supported = &generic_rs485_supported,
 };
 
 static int iot2040_rs485_config(struct uart_port *port,
@@ -461,6 +467,10 @@ 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),
@@ -485,6 +495,7 @@ 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,
 };
 
@@ -522,6 +533,7 @@ 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