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authorThomas Gleixner <tglx@linutronix.de>2013-04-25 20:31:49 +0000
committerThomas Gleixner <tglx@linutronix.de>2013-05-16 11:09:17 +0200
commit501f867064e95f9a6f540e60705be0937280e7ec (patch)
tree92cabb49d9e67f9824bd2d09a9872b02d69b3a97 /kernel/time/clockevents.c
parentccf33d6880f39a35158fff66db13000ae4943fac (diff)
clockevents: Provide sysfs interface
Provide a simple sysfs interface for the clockevent devices. Show the current active clockevent device. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: John Stultz <john.stultz@linaro.org> Cc: Magnus Damm <magnus.damm@gmail.com> Link: http://lkml.kernel.org/r/20130425143436.371634778@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel/time/clockevents.c')
-rw-r--r--kernel/time/clockevents.c86
1 files changed, 86 insertions, 0 deletions
diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c
index 89e394caa769..0a23f4f29934 100644
--- a/kernel/time/clockevents.c
+++ b/kernel/time/clockevents.c
@@ -16,6 +16,7 @@
#include <linux/init.h>
#include <linux/module.h>
#include <linux/smp.h>
+#include <linux/device.h>
#include "tick-internal.h"
@@ -460,4 +461,89 @@ void clockevents_notify(unsigned long reason, void *arg)
raw_spin_unlock_irqrestore(&clockevents_lock, flags);
}
EXPORT_SYMBOL_GPL(clockevents_notify);
+
+#ifdef CONFIG_SYSFS
+struct bus_type clockevents_subsys = {
+ .name = "clockevents",
+ .dev_name = "clockevent",
+};
+
+static DEFINE_PER_CPU(struct device, tick_percpu_dev);
+static struct tick_device *tick_get_tick_dev(struct device *dev);
+
+static ssize_t sysfs_show_current_tick_dev(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct tick_device *td;
+ ssize_t count = 0;
+
+ raw_spin_lock_irq(&clockevents_lock);
+ td = tick_get_tick_dev(dev);
+ if (td && td->evtdev)
+ count = snprintf(buf, PAGE_SIZE, "%s\n", td->evtdev->name);
+ raw_spin_unlock_irq(&clockevents_lock);
+ return count;
+}
+static DEVICE_ATTR(current_device, 0444, sysfs_show_current_tick_dev, NULL);
+
+#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
+static struct device tick_bc_dev = {
+ .init_name = "broadcast",
+ .id = 0,
+ .bus = &clockevents_subsys,
+};
+
+static struct tick_device *tick_get_tick_dev(struct device *dev)
+{
+ return dev == &tick_bc_dev ? tick_get_broadcast_device() :
+ &per_cpu(tick_cpu_device, dev->id);
+}
+
+static __init int tick_broadcast_init_sysfs(void)
+{
+ int err = device_register(&tick_bc_dev);
+
+ if (!err)
+ err = device_create_file(&tick_bc_dev, &dev_attr_current_device);
+ return err;
+}
+#else
+static struct tick_device *tick_get_tick_dev(struct device *dev)
+{
+ return &per_cpu(tick_cpu_device, dev->id);
+}
+static inline int tick_broadcast_init_sysfs(void) { return 0; }
#endif
+
+static int __init tick_init_sysfs(void)
+{
+ int cpu;
+
+ for_each_possible_cpu(cpu) {
+ struct device *dev = &per_cpu(tick_percpu_dev, cpu);
+ int err;
+
+ dev->id = cpu;
+ dev->bus = &clockevents_subsys;
+ err = device_register(dev);
+ if (!err)
+ err = device_create_file(dev, &dev_attr_current_device);
+ if (err)
+ return err;
+ }
+ return tick_broadcast_init_sysfs();
+}
+
+static int __init clockevents_init_sysfs(void)
+{
+ int err = subsys_system_register(&clockevents_subsys, NULL);
+
+ if (!err)
+ err = tick_init_sysfs();
+ return err;
+}
+device_initcall(clockevents_init_sysfs);
+#endif /* SYSFS */
+
+#endif /* GENERIC_CLOCK_EVENTS */