[PATCH] Serial: Avoid unbalanced IRQ wake disable during resume

["Govindraj.R" <govindraj.raja@ti.com>]

To avoid unbalanced IRQ wake disable, ensure that wakeups are disabled
only when wakeups have been successfully enabled.
Tested on OMAP3630SDP/ZOOM3.

Signed-off-by: Govindraj.R <govindraj.raja@ti.com>
Reported-by: Paul Walmsley <paul@pwsan.com>
Cc: Santosh Shilimkar <santosh.shilimkar@ti.com>
Cc: Kevin Hilman <khilman@deeprootsystems.com>
Cc: Greg KH <greg@kroah.com>
---
This patch is in conclusion to issue discussed in below thread:
http://www.spinics.net/lists/linux-omap/msg41356.html

 drivers/serial/serial_core.c |    8 ++++++--
 include/linux/serial_core.h  |    1 +
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c
index 9ffa5be..7ec1e11 100644
--- a/drivers/serial/serial_core.c
+++ b/drivers/serial/serial_core.c
@@ -1985,7 +1985,8 @@ int uart_suspend_port(struct uart_driver *drv, struct uart_port *uport)

 	tty_dev = device_find_child(uport->dev, &match, serial_match_port);
 	if (device_may_wakeup(tty_dev)) {
-		enable_irq_wake(uport->irq);
+		if (!enable_irq_wake(uport->irq))
+			uport->irq_wake = 1;
 		put_device(tty_dev);
 		mutex_unlock(&port->mutex);
 		return 0;
@@ -2051,7 +2052,10 @@ int uart_resume_port(struct uart_driver *drv, struct uart_port *uport)

 	tty_dev = device_find_child(uport->dev, &match, serial_match_port);
 	if (!uport->suspended && device_may_wakeup(tty_dev)) {
-		disable_irq_wake(uport->irq);
+		if (uport->irq_wake) {
+			disable_irq_wake(uport->irq);
+			uport->irq_wake = 0;
+		}
 		mutex_unlock(&port->mutex);
 		return 0;
 	}
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index 212eb4c..28b6698 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -361,6 +361,7 @@ struct uart_port {
 	struct device		*dev;			/* parent device */
 	unsigned char		hub6;			/* this should be in the 8250 driver */
 	unsigned char		suspended;
+	unsigned char		irq_wake;
 	unsigned char		unused[2];
 	void			*private_data;		/* generic platform data pointer */
 };
-- 
1.7.1