serial: uartps: Add support for cts-override

Having flow is configurable. Add support for the same by
checking for cts-override.
Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/xilinx_uartps.c

@@ -193,6 +193,7 @@ struct cdns_uart {
 	int			id;
 	struct notifier_block	clk_rate_change_nb;
 	u32			quirks;
+	bool cts_override;
 };
 struct cdns_platform_data {
 	u32 quirks;
@@ -1000,6 +1001,11 @@ static void cdns_uart_config_port(struct uart_port *port, int flags)
  */
 static unsigned int cdns_uart_get_mctrl(struct uart_port *port)
 {
+	struct cdns_uart *cdns_uart_data = port->private_data;
+
+	if (cdns_uart_data->cts_override)
+		return 0;
+
 	return TIOCM_CTS | TIOCM_DSR | TIOCM_CAR;
 }
 
@@ -1007,6 +1013,10 @@ static void cdns_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
 {
 	u32 val;
 	u32 mode_reg;
+	struct cdns_uart *cdns_uart_data = port->private_data;
+
+	if (cdns_uart_data->cts_override)
+		return;
 
 	val = readl(port->membase + CDNS_UART_MODEMCR);
 	mode_reg = readl(port->membase + CDNS_UART_MR);
@@ -1665,6 +1675,8 @@ static int cdns_uart_probe(struct platform_device *pdev)
 		console_port = NULL;
 #endif
 
+	cdns_uart_data->cts_override = of_property_read_bool(pdev->dev.of_node,
+							     "cts-override");
 	return 0;
 
 err_out_pm_disable: