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

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Date:	Thu, 8 Sep 2011 16:52:47 -0700
From:	Andrew Morton <akpm@...ux-foundation.org>
To:	Donggeun Kim <dg77.kim@...sung.com>
Cc:	rtc-linux@...glegroups.com, a.zummo@...ertech.it,
	linux-kernel@...r.kernel.org, myungjoo.ham@...sung.com,
	kyungmin.park@...sung.com
Subject: Re: [PATCH] rtc: rtc-s3c: fix no occurrence of alarm interrupt

On Wed, 31 Aug 2011 19:21:50 +0900
Donggeun Kim <dg77.kim@...sung.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;
 
_

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