serial: 8250: export serial8250_do_set_divisor()

Some drivers could call serial8250_do_set_divisor() to complete its
own set_divisor routine. Export this symbol for code reusing.
Signed-off-by: NJisheng Zhang <Jisheng.Zhang@synaptics.com>
Reviewed-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/8250/8250_port.c

@@ -2580,8 +2580,8 @@ static unsigned char serial8250_compute_lcr(struct uart_8250_port *up,
 	return cval;
 }
 
-static void serial8250_do_set_divisor(struct uart_port *port, unsigned int baud,
-			    unsigned int quot, unsigned int quot_frac)
+void serial8250_do_set_divisor(struct uart_port *port, unsigned int baud,
+			       unsigned int quot, unsigned int quot_frac)
 {
 	struct uart_8250_port *up = up_to_u8250p(port);
 
@@ -2612,6 +2612,7 @@ static void serial8250_do_set_divisor(struct uart_port *port, unsigned int baud,
 		serial_port_out(port, 0x2, quot_frac);
 	}
 }
+EXPORT_SYMBOL_GPL(serial8250_do_set_divisor);
 
 static void serial8250_set_divisor(struct uart_port *port, unsigned int baud,
 				   unsigned int quot, unsigned int quot_frac)

include/linux/serial_8250.h

@@ -160,6 +160,9 @@ extern void serial8250_do_shutdown(struct uart_port *port);
 extern void serial8250_do_pm(struct uart_port *port, unsigned int state,
 			     unsigned int oldstate);
 extern void serial8250_do_set_mctrl(struct uart_port *port, unsigned int mctrl);
+extern void serial8250_do_set_divisor(struct uart_port *port, unsigned int baud,
+				      unsigned int quot,
+				      unsigned int quot_frac);
 extern int fsl8250_handle_irq(struct uart_port *port);
 int serial8250_handle_irq(struct uart_port *port, unsigned int iir);
 unsigned char serial8250_rx_chars(struct uart_8250_port *up, unsigned char lsr);