Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 501f8670 authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

clockevents: Provide sysfs interface 



Provide a simple sysfs interface for the clockevent devices. Show the
current active clockevent device.

Signed-off-by: default avatarThomas 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: default avatarThomas Gleixner <tglx@linutronix.de>
parent ccf33d68

kernel/time/clockevents.c

+86 −0
Original line number Diff line number Diff line
@@ -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 */