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authorBen Dooks <ben@simtec.co.uk>2009-10-30 00:30:25 +0000
committerWim Van Sebroeck <wim@iguana.be>2009-12-04 13:20:28 +0000
commite02f838eedef1533f7a1bcf21fe724c3c93093f9 (patch)
treed1c032ac403a6ebf90fbc8e3294030b3eb83ab2d /drivers/watchdog
parent22763c5cf3690a681551162c15d34d935308c8d7 (diff)
[WATCHDOG] CPUFREQ: S3C24XX Watchdog frequency scaling support.
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>
Diffstat (limited to 'drivers/watchdog')
-rw-r--r--drivers/watchdog/s3c2410_wdt.c89
1 files changed, 86 insertions, 3 deletions
diff --git a/drivers/watchdog/s3c2410_wdt.c b/drivers/watchdog/s3c2410_wdt.c
index b57ac6b49147..85b93e15d011 100644
--- a/drivers/watchdog/s3c2410_wdt.c
+++ b/drivers/watchdog/s3c2410_wdt.c
@@ -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;