rtc: Suppress duplicate enable/disable of WM8350 update interrupt

Unlike the wm8350-custom code genirq nests enable and disable calls
so we can't just unconditionally mask or unmask the interrupt,
we need to remember the state we set and only mask or unmask when
there is a real change.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Alessandro Zummo <a.zummo@towertech.it>
Cc: rtc-linux@googlegroups.com
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

drivers/rtc/rtc-wm8350.c

@@ -307,11 +307,18 @@ static int wm8350_rtc_update_irq_enable(struct device *dev,
 {
 	struct wm8350 *wm8350 = dev_get_drvdata(dev);
 
+	/* Suppress duplicate changes since genirq nests enable and
+	 * disable calls. */
+	if (enabled == wm8350->rtc.update_enabled)
+		return 0;
+
 	if (enabled)
 		wm8350_unmask_irq(wm8350, WM8350_IRQ_RTC_SEC);
 	else
 		wm8350_mask_irq(wm8350, WM8350_IRQ_RTC_SEC);
 
+	wm8350->rtc.update_enabled = enabled;
+
 	return 0;
 }
 

include/linux/mfd/wm8350/rtc.h

@@ -263,6 +263,7 @@ struct wm8350_rtc {
 	struct platform_device *pdev;
 	struct rtc_device *rtc;
 	int alarm_enabled;      /* used over suspend/resume */
+	int update_enabled;
 };
 
 #endif