8250: use callbacks to access UART_DLL/UART_DLM

Some UART HW has a single register combining UART_DLL/UART_DLM
(this was probably forgotten in the change that introduced the
callbacks, commit b32b19b8ffc05cbd3bf91c65e205f6a912ca15d9)

Fixes: b32b19b8ffc0 ("[SERIAL] 8250: set divisor register correctly ...")

Signed-off-by: Sebastian Frias <sf84@laposte.net>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index 01a85a7..c2b650a 100644 (file)
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -813,22 +813,16 @@ static int size_fifo(struct uart_8250_port *up)
  */
 static unsigned int autoconfig_read_divisor_id(struct uart_8250_port *p)
 {
-       unsigned char old_dll, old_dlm, old_lcr;
-       unsigned int id;
+       unsigned char old_lcr;
+       unsigned int id, old_dl;
 
        old_lcr = serial_in(p, UART_LCR);
        serial_out(p, UART_LCR, UART_LCR_CONF_MODE_A);
+       old_dl = serial_dl_read(p);
+       serial_dl_write(p, 0);
+       id = serial_dl_read(p);
+       serial_dl_write(p, old_dl);
 
-       old_dll = serial_in(p, UART_DLL);
-       old_dlm = serial_in(p, UART_DLM);
-
-       serial_out(p, UART_DLL, 0);
-       serial_out(p, UART_DLM, 0);
-
-       id = serial_in(p, UART_DLL) | serial_in(p, UART_DLM) << 8;
-
-       serial_out(p, UART_DLL, old_dll);
-       serial_out(p, UART_DLM, old_dlm);
        serial_out(p, UART_LCR, old_lcr);
 
        return id;