serial: samsung: wait for transfer completion before clock disable

commit 1ff383a4c3eda8893ec61b02831826e1b1f46b41 upstream. 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. Signed-off-by: Robert Baldyga <r.baldyga@samsung.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: samsung: wait for transfer completion before clock disable
commit 1ff383a4c3eda8893ec61b02831826e1b1f46b41 upstream. 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. Signed-off-by: Robert Baldyga <r.baldyga@samsung.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Robert Baldyga · Greg Kroah-Hartman
1 parent 0fd0e781e9
Showing 1 changed file with 4 additions and 0 deletions Side-by-side Diff
drivers/tty/serial/samsung.c
@@ -559,11 +559,15 @@
 			      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);
...	...	@@ -559,11 +559,15 @@
559	559	unsigned int old)
560	560	{
561	561	struct s3c24xx_uart_port *ourport = to_ourport(port);
	562	+ int timeout = 10000;
562	563
563	564	ourport->pm_level = level;
564	565
565	566	switch (level) {
566	567	case 3:
	568	+ while (--timeout && !s3c24xx_serial_txempty_nofifo(port))
	569	+ udelay(100);
	570	+
567	571	if (!IS_ERR(ourport->baudclk))
568	572	clk_disable_unprepare(ourport->baudclk);
569	573