drivers/rtc/rtc-s3c.c: fixup wake support for rtc

The driver is not balancing set_irq and disable_irq_wake() calls, so
ensure that it keeps track of whether the wake is enabled.

The fixes the following error on S3C6410 devices:

  WARNING: at kernel/irq/manage.c:382 set_irq_wake+0x84/0xec()
  Unbalanced IRQ 92 wake disable
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/rtc/rtc-s3c.c

@@ -46,6 +46,7 @@ static struct clk *rtc_clk;
 static void __iomem *s3c_rtc_base;
 static int s3c_rtc_alarmno = NO_IRQ;
 static int s3c_rtc_tickno  = NO_IRQ;
+static bool wake_en;
 static enum s3c_cpu_type s3c_rtc_cpu_type;
 
 static DEFINE_SPINLOCK(s3c_rtc_pie_lock);
@@ -562,8 +563,12 @@ static int s3c_rtc_suspend(struct platform_device *pdev, pm_message_t state)
 	}
 	s3c_rtc_enable(pdev, 0);
 
-	if (device_may_wakeup(&pdev->dev))
-		enable_irq_wake(s3c_rtc_alarmno);
+	if (device_may_wakeup(&pdev->dev) && !wake_en) {
+		if (enable_irq_wake(s3c_rtc_alarmno) == 0)
+			wake_en = true;
+		else
+			dev_err(&pdev->dev, "enable_irq_wake failed\n");
+	}
 
 	return 0;
 }
@@ -579,8 +584,10 @@ static int s3c_rtc_resume(struct platform_device *pdev)
 		writew(tmp | ticnt_en_save, s3c_rtc_base + S3C2410_RTCCON);
 	}
 
-	if (device_may_wakeup(&pdev->dev))
+	if (device_may_wakeup(&pdev->dev) && wake_en) {
 		disable_irq_wake(s3c_rtc_alarmno);
+		wake_en = false;
+	}
 
 	return 0;
 }