serial: samsung: Reorder the sequence of clock control when call s3c24xx_serial_set_t...

This patch fixes the broken serial log when changing the clock source
of uart device. Before disabling the original clock source, this patch
enables the new clock source to protect the clock off state for a split second.

Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Reviewed-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/samsung.c b/drivers/tty/serial/samsung.c
index ac7f8df5440640d7ec2afcb188abddd75b915916..99bb23161dd6e5f3ac514f9a9218cd4590467169 100644 (file)
--- a/drivers/tty/serial/samsung.c
+++ b/drivers/tty/serial/samsung.c
@@ -1271,6 +1271,8 @@ static void s3c24xx_serial_set_termios(struct uart_port *port,
        /* check to see if we need  to change clock source */
 
        if (ourport->baudclk != clk) {
+               clk_prepare_enable(clk);
+
                s3c24xx_serial_setsource(port, clk_sel);
 
                if (!IS_ERR(ourport->baudclk)) {
@@ -1278,8 +1280,6 @@ static void s3c24xx_serial_set_termios(struct uart_port *port,
                        ourport->baudclk = ERR_PTR(-EINVAL);
                }
 
-               clk_prepare_enable(clk);
-
                ourport->baudclk = clk;
                ourport->baudclk_rate = clk ? clk_get_rate(clk) : 0;
        }