[PATCH] rtc: rtc-s3c: fix no occurrence of alarm interrupt

[PATCH] rtc: rtc-s3c: fix no occurrence of alarm interrupt

[Donggeun Kim]

The driver does not generate alarm interrupt
even though time for alarm is set.
This results from disabling rtc_clk after setting time for alarm.
To generate alarm interrupt,
the driver should maintain enabled state for rtc_clk
until alarm interrupt occurs.
This patch allows to generate alarm interrupt.

Signed-off-by: Donggeun Kim <dg77.kim@samsung.com>
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
---
 drivers/rtc/rtc-s3c.c |   26 ++++++++++++++++++++++++++
 1 files changed, 26 insertions(+), 0 deletions(-)

diff --git a/drivers/rtc/rtc-s3c.c b/drivers/rtc/rtc-s3c.c
index 4e7c04e..b68697e 100644
--- a/drivers/rtc/rtc-s3c.c
+++ b/drivers/rtc/rtc-s3c.c
@@ -50,6 +50,27 @@ static bool wake_en;
 static enum s3c_cpu_type s3c_rtc_cpu_type;
 
 static DEFINE_SPINLOCK(s3c_rtc_pie_lock);
+static DEFINE_SPINLOCK(s3c_rtc_alarm_clk_lock);
+
+static void s3c_rtc_alarm_clk_enable(bool enable)
+{
+	static bool alarm_clk_enabled;
+	unsigned long irq_flags;
+
+	spin_lock_irqsave(&s3c_rtc_alarm_clk_lock, irq_flags);
+	if (enable) {
+		if (!alarm_clk_enabled) {
+			clk_enable(rtc_clk);
+			alarm_clk_enabled = true;
+		}
+	} else {
+		if (alarm_clk_enabled) {
+			clk_disable(rtc_clk);
+			alarm_clk_enabled = false;
+		}
+	}
+	spin_unlock_irqrestore(&s3c_rtc_alarm_clk_lock, irq_flags);
+}
 
 /* IRQ Handlers */
 
@@ -64,6 +85,9 @@ static irqreturn_t s3c_rtc_alarmirq(int irq, void *id)
 		writeb(S3C2410_INTP_ALM, s3c_rtc_base + S3C2410_INTP);
 
 	clk_disable(rtc_clk);
+
+	s3c_rtc_alarm_clk_enable(false);
+
 	return IRQ_HANDLED;
 }
 
@@ -97,6 +121,8 @@ static int s3c_rtc_setaie(struct device *dev, unsigned int enabled)
 	writeb(tmp, s3c_rtc_base + S3C2410_RTCALM);
 	clk_disable(rtc_clk);
 
+	s3c_rtc_alarm_clk_enable(enabled);
+
 	return 0;
 }
 
-- 
1.7.4.1

Re: [PATCH] rtc: rtc-s3c: fix no occurrence of alarm interrupt

[Andrew Morton]

On Wed, 31 Aug 2011 19:21:50 +0900
Donggeun Kim <dg77.kim@samsung.com> wrote:

> The driver does not generate alarm interrupt
> even though time for alarm is set.
> This results from disabling rtc_clk after setting time for alarm.
> To generate alarm interrupt,
> the driver should maintain enabled state for rtc_clk
> until alarm interrupt occurs.
> This patch allows to generate alarm interrupt.
> 
> ...
>
> +static DEFINE_SPINLOCK(s3c_rtc_alarm_clk_lock);
> +
> +static void s3c_rtc_alarm_clk_enable(bool enable)
> +{
> +	static bool alarm_clk_enabled;
> +	unsigned long irq_flags;
> +
> +	spin_lock_irqsave(&s3c_rtc_alarm_clk_lock, irq_flags);
> +	if (enable) {
> +		if (!alarm_clk_enabled) {
> +			clk_enable(rtc_clk);
> +			alarm_clk_enabled = true;
> +		}
> +	} else {
> +		if (alarm_clk_enabled) {
> +			clk_disable(rtc_clk);
> +			alarm_clk_enabled = false;
> +		}
> +	}
> +	spin_unlock_irqrestore(&s3c_rtc_alarm_clk_lock, irq_flags);
> +}

s3c_rtc_alarm_clk_lock is only used within s3c_rtc_alarm_clk_enable(),
so we can reduce its scope:

--- a/drivers/rtc/rtc-s3c.c~rtc-rtc-s3c-fix-no-occurrence-of-alarm-interrupt-fix
+++ a/drivers/rtc/rtc-s3c.c
@@ -50,10 +50,10 @@ static bool wake_en;
 static enum s3c_cpu_type s3c_rtc_cpu_type;
 
 static DEFINE_SPINLOCK(s3c_rtc_pie_lock);
-static DEFINE_SPINLOCK(s3c_rtc_alarm_clk_lock);
 
 static void s3c_rtc_alarm_clk_enable(bool enable)
 {
+	static DEFINE_SPINLOCK(s3c_rtc_alarm_clk_lock);
 	static bool alarm_clk_enabled;
 	unsigned long irq_flags;
 
_