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Commit e02f838e authored by Ben Dooks's avatar Ben Dooks Committed by Wim Van Sebroeck
Browse files

[WATCHDOG] CPUFREQ: S3C24XX Watchdog frequency scaling support. 



Add support for CPU frequency scaling to the S3C24XX Watchdog
driver.

Signed-off-by: default avatarSimtec Linux Team <linux@simtec.co.uk>
Signed-off-by: default avatarBen Dooks <ben@simtec.co.uk>
Signed-off-by: default avatarWim Van Sebroeck <wim@iguana.be>
parent 22763c5c

drivers/watchdog/s3c2410_wdt.c

+86 −3
Original line number Diff line number Diff line
@@ -36,6 +36,7 @@ 
#include <linux/clk.h>

#include <linux/uaccess.h>

#include <linux/io.h>

#include <linux/cpufreq.h>



#include <mach/map.h>
@@ -142,9 +143,14 @@ static void s3c2410wdt_start(void) 
	spin_unlock(&wdt_lock);

}



static inline int s3c2410wdt_is_running(void)

{

	return readl(wdt_base + S3C2410_WTCON) & S3C2410_WTCON_ENABLE;

}



static int s3c2410wdt_set_heartbeat(int timeout)

{

	unsigned int freq = clk_get_rate(wdt_clock);

	unsigned long freq = clk_get_rate(wdt_clock);

	unsigned int count;

	unsigned int divisor = 1;

	unsigned long wtcon;
@@ -155,7 +161,7 @@ static int s3c2410wdt_set_heartbeat(int timeout) 
	freq /= 128;

	count = timeout * freq;



	DBG("%s: count=%d, timeout=%d, freq=%d\n",

	DBG("%s: count=%d, timeout=%d, freq=%lu\n",

	    __func__, count, timeout, freq);



	/* if the count is bigger than the watchdog register,
@@ -324,6 +330,73 @@ static irqreturn_t s3c2410wdt_irq(int irqno, void *param) 
	s3c2410wdt_keepalive();

	return IRQ_HANDLED;

}





#ifdef CONFIG_CPU_FREQ



static int s3c2410wdt_cpufreq_transition(struct notifier_block *nb,

					  unsigned long val, void *data)

{

	int ret;



	if (!s3c2410wdt_is_running())

		goto done;



	if (val == CPUFREQ_PRECHANGE) {

		/* To ensure that over the change we don't cause the

		 * watchdog to trigger, we perform an keep-alive if

		 * the watchdog is running.

		 */



		s3c2410wdt_keepalive();

	} else if (val == CPUFREQ_POSTCHANGE) {

		s3c2410wdt_stop();



		ret = s3c2410wdt_set_heartbeat(tmr_margin);



		if (ret >= 0)

			s3c2410wdt_start();

		else

			goto err;

	}



done:

	return 0;



 err:

	dev_err(wdt_dev, "cannot set new value for timeout %d\n", tmr_margin);

	return ret;

}



static struct notifier_block s3c2410wdt_cpufreq_transition_nb = {

	.notifier_call	= s3c2410wdt_cpufreq_transition,

};



static inline int s3c2410wdt_cpufreq_register(void)

{

	return cpufreq_register_notifier(&s3c2410wdt_cpufreq_transition_nb,

					 CPUFREQ_TRANSITION_NOTIFIER);

}



static inline void s3c2410wdt_cpufreq_deregister(void)

{

	cpufreq_unregister_notifier(&s3c2410wdt_cpufreq_transition_nb,

				    CPUFREQ_TRANSITION_NOTIFIER);

}



#else

static inline int s3c2410wdt_cpufreq_register(void)

{

	return 0;

}



static inline void s3c2410wdt_cpufreq_deregister(void)

{

}

#endif







/* device interface */



static int __devinit s3c2410wdt_probe(struct platform_device *pdev)
@@ -387,6 +460,11 @@ static int __devinit s3c2410wdt_probe(struct platform_device *pdev) 


	clk_enable(wdt_clock);



	if (s3c2410wdt_cpufreq_register() < 0) {

		printk(KERN_ERR PFX "failed to register cpufreq\n");

		goto err_clk;

	}



	/* see if we can actually set the requested timer margin, and if

	 * not, try the default value */
@@ -407,7 +485,7 @@ static int __devinit s3c2410wdt_probe(struct platform_device *pdev) 
	if (ret) {

		dev_err(dev, "cannot register miscdev on minor=%d (%d)\n",

			WATCHDOG_MINOR, ret);

		goto err_clk;

		goto err_cpufreq;

	}



	if (tmr_atboot && started == 0) {
@@ -432,6 +510,9 @@ static int __devinit s3c2410wdt_probe(struct platform_device *pdev) 


	return 0;



 err_cpufreq:

	s3c2410wdt_cpufreq_deregister();



 err_clk:

	clk_disable(wdt_clock);

	clk_put(wdt_clock);
@@ -451,6 +532,8 @@ static int __devinit s3c2410wdt_probe(struct platform_device *pdev) 


static int __devexit s3c2410wdt_remove(struct platform_device *dev)

{

	s3c2410wdt_cpufreq_deregister();



	release_resource(wdt_mem);

	kfree(wdt_mem);

	wdt_mem = NULL;