From: Doug Anderson Date: Mon, 25 Nov 2013 23:36:43 +0000 (-0800) Subject: watchdog: s3c2410_wdt: Only register for cpufreq on ARM_S3C24XX_CPUFREQ X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=0f1dd98d896efb956d474754b5d2f0c420d40192;p=openwrt%2Fstaging%2Fblogic.git watchdog: s3c2410_wdt: Only register for cpufreq on ARM_S3C24XX_CPUFREQ On modern SoCs the watchdog timer is parented on a clock that doesn't change every time we have a cpufreq change. That means we don't need to constantly adjust the watchdog timer, so avoid registering for and dealing with cpufreq transitions unless we've actually got CONFIG_ARM_S3C24XX_CPUFREQ defined. Note that this is more than just an optimization. The s3c2410 watchdog driver actually pats the watchdog on every CPU frequency change. On modern systems these happen many times per second (even in a system where "nothing" is happening). That effectively makes any userspace watchdog program useless (the watchdog is constantly patted by the kernel). If we need ARM_S3C24XX_CPUFREQ defined on a multiplatform kernel we'll need to make sure that kernel supports common clock and change this to user common clock framework. Signed-off-by: Doug Anderson Reviewed-by: Tomasz Figa Reviewed-by: Guenter Roeck Signed-off-by: Wim Van Sebroeck --- diff --git a/drivers/watchdog/s3c2410_wdt.c b/drivers/watchdog/s3c2410_wdt.c index 7d8fd041ee25..c1ada330e125 100644 --- a/drivers/watchdog/s3c2410_wdt.c +++ b/drivers/watchdog/s3c2410_wdt.c @@ -264,7 +264,7 @@ static irqreturn_t s3c2410wdt_irq(int irqno, void *param) return IRQ_HANDLED; } -#ifdef CONFIG_CPU_FREQ +#ifdef CONFIG_ARM_S3C24XX_CPUFREQ static int s3c2410wdt_cpufreq_transition(struct notifier_block *nb, unsigned long val, void *data)