From 664fcc116904a7414f7bbd0831c973cbd28b59ad Mon Sep 17 00:00:00 2001 From: Chanwoo Choi Date: Thu, 21 Apr 2016 18:58:31 +0900 Subject: [PATCH] serial: samsung: Reorder the sequence of clock control when call s3c24xx_serial_set_termios() [ Upstream commit b8995f527aac143e83d3900ff39357651ea4e0f6 ] 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 Reviewed-by: Marek Szyprowski Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/tty/serial/samsung.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/tty/serial/samsung.c b/drivers/tty/serial/samsung.c index 1e0d9b8c48c93..e42cb6bdd31d7 100644 --- a/drivers/tty/serial/samsung.c +++ b/drivers/tty/serial/samsung.c @@ -1288,6 +1288,8 @@ 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)) { @@ -1295,8 +1297,6 @@ 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; }