sh: sh-rtc carry interrupt rework

This patch modifies the SuperH RTC driver to only
enable carry interrupts when needed. So by default
no interrupts are enabled with this patch. Without
this patch a suspending system will most likely
wake up by the carry interrupt regardless if the
alarm interrupt has been enabled or not.

Signed-off-by: Magnus Damm <damm@igel.co.jp>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/drivers/rtc/rtc-sh.c b/drivers/rtc/rtc-sh.c
index aeff251..21e7435 100644
--- a/drivers/rtc/rtc-sh.c
+++ b/drivers/rtc/rtc-sh.c
@@ -319,6 +319,25 @@
 	return 0;
 }
 
+static inline void sh_rtc_setcie(struct device *dev, unsigned int enable)
+{
+	struct sh_rtc *rtc = dev_get_drvdata(dev);
+	unsigned int tmp;
+
+	spin_lock_irq(&rtc->lock);
+
+	tmp = readb(rtc->regbase + RCR1);
+
+	if (!enable)
+		tmp &= ~RCR1_CIE;
+	else
+		tmp |= RCR1_CIE;
+
+	writeb(tmp, rtc->regbase + RCR1);
+
+	spin_unlock_irq(&rtc->lock);
+}
+
 static int sh_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
 {
 	struct sh_rtc *rtc = dev_get_drvdata(dev);
@@ -335,9 +354,11 @@
 		break;
 	case RTC_UIE_OFF:
 		rtc->periodic_freq &= ~PF_OXS;
+		sh_rtc_setcie(dev, 0);
 		break;
 	case RTC_UIE_ON:
 		rtc->periodic_freq |= PF_OXS;
+		sh_rtc_setcie(dev, 1);
 		break;
 	case RTC_IRQP_READ:
 		ret = put_user(rtc->rtc_dev->irq_freq,
@@ -400,6 +421,10 @@
 		tm->tm_sec--;
 #endif
 
+	/* only keep the carry interrupt enabled if UIE is on */
+	if (!(rtc->periodic_freq & PF_OXS))
+		sh_rtc_setcie(dev, 0);
+
 	dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
 		"mday=%d, mon=%d, year=%d, wday=%d\n",
 		__func__,
@@ -616,7 +641,6 @@
 {
 	struct sh_rtc *rtc;
 	struct resource *res;
-	unsigned int tmp;
 	int ret;
 
 	rtc = kzalloc(sizeof(struct sh_rtc), GFP_KERNEL);
@@ -676,8 +700,6 @@
 	}
 
 	rtc->rtc_dev->max_user_freq = 256;
-	rtc->rtc_dev->irq_freq = 1;
-	rtc->periodic_freq = 0x60;
 
 	platform_set_drvdata(pdev, rtc);
 
@@ -724,11 +746,12 @@
 		}
 	}
 
-	tmp = readb(rtc->regbase + RCR1);
-	tmp &= ~RCR1_CF;
-	tmp |= RCR1_CIE;
-	writeb(tmp, rtc->regbase + RCR1);
-
+	/* everything disabled by default */
+	rtc->periodic_freq = 0;
+	rtc->rtc_dev->irq_freq = 0;
+	sh_rtc_setpie(&pdev->dev, 0);
+	sh_rtc_setaie(&pdev->dev, 0);
+	sh_rtc_setcie(&pdev->dev, 0);
 	return 0;
 
 err_unmap:
@@ -750,6 +773,7 @@
 
 	sh_rtc_setpie(&pdev->dev, 0);
 	sh_rtc_setaie(&pdev->dev, 0);
+	sh_rtc_setcie(&pdev->dev, 0);
 
 	free_irq(rtc->periodic_irq, rtc);
 	if (rtc->carry_irq > 0) {