rtc: s3c: fix disabled clocks for alarm

The clock enable/disable codes for alarm have been removed from
commit 24e1455493da ("drivers/rtc/rtc-s3c.c: delete duplicate clock
control") and the clocks are disabled even if alarm is set, so alarm
interrupt can't happen.

The s3c_rtc_setaie function can be called several times with 'enabled'
argument having same value, so it needs to check whether clocks are
enabled or not.

Signed-off-by: Joonyoung Shim <jy0922.shim@samsung.com>
Cc: <stable@vger.kernel.org> # v4.1
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

drivers/rtc/rtc-s3c.c

@@ -39,6 +39,7 @@ struct s3c_rtc {
 	void __iomem *base;
 	struct clk *rtc_clk;
 	struct clk *rtc_src_clk;
+	bool clk_disabled;
 
 	struct s3c_rtc_data *data;
 
@@ -71,9 +72,12 @@ static void s3c_rtc_enable_clk(struct s3c_rtc *info)
 	unsigned long irq_flags;
 
 	spin_lock_irqsave(&info->alarm_clk_lock, irq_flags);
-	clk_enable(info->rtc_clk);
-	if (info->data->needs_src_clk)
-		clk_enable(info->rtc_src_clk);
+	if (info->clk_disabled) {
+		clk_enable(info->rtc_clk);
+		if (info->data->needs_src_clk)
+			clk_enable(info->rtc_src_clk);
+		info->clk_disabled = false;
+	}
 	spin_unlock_irqrestore(&info->alarm_clk_lock, irq_flags);
 }
 
@@ -82,9 +86,12 @@ static void s3c_rtc_disable_clk(struct s3c_rtc *info)
 	unsigned long irq_flags;
 
 	spin_lock_irqsave(&info->alarm_clk_lock, irq_flags);
-	if (info->data->needs_src_clk)
-		clk_disable(info->rtc_src_clk);
-	clk_disable(info->rtc_clk);
+	if (!info->clk_disabled) {
+		if (info->data->needs_src_clk)
+			clk_disable(info->rtc_src_clk);
+		clk_disable(info->rtc_clk);
+		info->clk_disabled = true;
+	}
 	spin_unlock_irqrestore(&info->alarm_clk_lock, irq_flags);
 }
 
@@ -128,6 +135,11 @@ static int s3c_rtc_setaie(struct device *dev, unsigned int enabled)
 
 	s3c_rtc_disable_clk(info);
 
+	if (enabled)
+		s3c_rtc_enable_clk(info);
+	else
+		s3c_rtc_disable_clk(info);
+
 	return 0;
 }