From 1ff383a4c3eda8893ec61b02831826e1b1f46b41 Mon Sep 17 00:00:00 2001 From: Robert Baldyga Date: Mon, 24 Nov 2014 07:56:21 +0100 Subject: [PATCH] serial: samsung: wait for transfer completion before clock disable This patch adds waiting until transmit buffer and shifter will be empty before clock disabling. Without this fix it's possible to have clock disabled while data was not transmited yet, which causes unproper state of TX line and problems in following data transfers. Cc: # v2.6.26+ Signed-off-by: Robert Baldyga Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/samsung.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/tty/serial/samsung.c b/drivers/tty/serial/samsung.c index 796c04c77dc1..d36b2bd39e30 100644 --- a/drivers/tty/serial/samsung.c +++ b/drivers/tty/serial/samsung.c @@ -559,11 +559,15 @@ static void s3c24xx_serial_pm(struct uart_port *port, unsigned int level, unsigned int old) { struct s3c24xx_uart_port *ourport = to_ourport(port); + int timeout = 10000; ourport->pm_level = level; switch (level) { case 3: + while (--timeout && !s3c24xx_serial_txempty_nofifo(port)) + udelay(100); + if (!IS_ERR(ourport->baudclk)) clk_disable_unprepare(ourport->baudclk); -- 2.39.5