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[WATCHDOG] CPUFREQ: S3C24XX Watchdog frequency scaling support.

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

Signed-off-by: Simtec Linux Team <linux@simtec.co.uk>
Signed-off-by: Ben Dooks <ben@simtec.co.uk>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
This commit is contained in:
Ben Dooks 2009-10-30 00:30:25 +00:00 committed by Wim Van Sebroeck
parent 22763c5cf3
commit e02f838eed
1 changed files with 86 additions and 3 deletions
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89
drivers/watchdog/s3c2410_wdt.c
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@ -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;