[deliverable/linux.git] / drivers / leds / trigger / ledtrig-cpu.c

/*
 * ledtrig-cpu.c - LED trigger based on CPU activity
 *
 * This LED trigger will be registered for each possible CPU and named as
 * cpu0, cpu1, cpu2, cpu3, etc.
 *
 * It can be bound to any LED just like other triggers using either a
 * board file or via sysfs interface.
 *
 * An API named ledtrig_cpu is exported for any user, who want to add CPU
 * activity indication in their code
 *
 * Copyright 2011 Linus Walleij <linus.walleij@linaro.org>
 * Copyright 2011 - 2012 Bryan Wu <bryan.wu@canonical.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/percpu.h>
#include <linux/syscore_ops.h>
#include <linux/rwsem.h>
#include <linux/cpu.h>
#include "../leds.h"

#define MAX_NAME_LEN	8

struct led_trigger_cpu {
	char name[MAX_NAME_LEN];
	struct led_trigger *_trig;
};

static DEFINE_PER_CPU(struct led_trigger_cpu, cpu_trig);

/**
 * ledtrig_cpu - emit a CPU event as a trigger
 * @evt: CPU event to be emitted
 *
 * Emit a CPU event on a CPU core, which will trigger a
 * binded LED to turn on or turn off.
 */
void ledtrig_cpu(enum cpu_led_event ledevt)
{
	struct led_trigger_cpu *trig = &__get_cpu_var(cpu_trig);

	/* Locate the correct CPU LED */
	switch (ledevt) {
	case CPU_LED_IDLE_END:
	case CPU_LED_START:
		/* Will turn the LED on, max brightness */
		led_trigger_event(trig->_trig, LED_FULL);
		break;

	case CPU_LED_IDLE_START:
	case CPU_LED_STOP:
	case CPU_LED_HALTED:
		/* Will turn the LED off */
		led_trigger_event(trig->_trig, LED_OFF);
		break;

	default:
		/* Will leave the LED as it is */
		break;
	}
}
EXPORT_SYMBOL(ledtrig_cpu);

static int ledtrig_cpu_syscore_suspend(void)
{
	ledtrig_cpu(CPU_LED_STOP);
	return 0;
}

static void ledtrig_cpu_syscore_resume(void)
{
	ledtrig_cpu(CPU_LED_START);
}

static void ledtrig_cpu_syscore_shutdown(void)
{
	ledtrig_cpu(CPU_LED_HALTED);
}

static struct syscore_ops ledtrig_cpu_syscore_ops = {
	.shutdown	= ledtrig_cpu_syscore_shutdown,
	.suspend	= ledtrig_cpu_syscore_suspend,
	.resume		= ledtrig_cpu_syscore_resume,
};

static int ledtrig_cpu_notify(struct notifier_block *self,
					   unsigned long action, void *hcpu)
{
	switch (action & ~CPU_TASKS_FROZEN) {
	case CPU_STARTING:
		ledtrig_cpu(CPU_LED_START);
		break;
	case CPU_DYING:
		ledtrig_cpu(CPU_LED_STOP);
		break;
	}

	return NOTIFY_OK;
}


static struct notifier_block ledtrig_cpu_nb = {
	.notifier_call = ledtrig_cpu_notify,
};

static int __init ledtrig_cpu_init(void)
{
	int cpu;

	/* Supports up to 9999 cpu cores */
	BUILD_BUG_ON(CONFIG_NR_CPUS > 9999);

	/*
	 * Registering CPU led trigger for each CPU core here
	 * ignores CPU hotplug, but after this CPU hotplug works
	 * fine with this trigger.
	 */
	for_each_possible_cpu(cpu) {
		struct led_trigger_cpu *trig = &per_cpu(cpu_trig, cpu);

		snprintf(trig->name, MAX_NAME_LEN, "cpu%d", cpu);

		led_trigger_register_simple(trig->name, &trig->_trig);
	}

	register_syscore_ops(&ledtrig_cpu_syscore_ops);
	register_cpu_notifier(&ledtrig_cpu_nb);

	pr_info("ledtrig-cpu: registered to indicate activity on CPUs\n");

	return 0;
}
module_init(ledtrig_cpu_init);

static void __exit ledtrig_cpu_exit(void)
{
	int cpu;

	unregister_cpu_notifier(&ledtrig_cpu_nb);

	for_each_possible_cpu(cpu) {
		struct led_trigger_cpu *trig = &per_cpu(cpu_trig, cpu);

		led_trigger_unregister_simple(trig->_trig);
		trig->_trig = NULL;
		memset(trig->name, 0, MAX_NAME_LEN);
	}

	unregister_syscore_ops(&ledtrig_cpu_syscore_ops);
}
module_exit(ledtrig_cpu_exit);

MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");
MODULE_AUTHOR("Bryan Wu <bryan.wu@canonical.com>");
MODULE_DESCRIPTION("CPU LED trigger");
MODULE_LICENSE("GPL");
Commit	Line	Data
8f88731d BW	1	/*
	2	* ledtrig-cpu.c - LED trigger based on CPU activity
	3	*
	4	* This LED trigger will be registered for each possible CPU and named as
	5	* cpu0, cpu1, cpu2, cpu3, etc.
	6	*
	7	* It can be bound to any LED just like other triggers using either a
	8	* board file or via sysfs interface.
	9	*
	10	* An API named ledtrig_cpu is exported for any user, who want to add CPU
	11	* activity indication in their code
	12	*
	13	* Copyright 2011 Linus Walleij <linus.walleij@linaro.org>
	14	* Copyright 2011 - 2012 Bryan Wu <bryan.wu@canonical.com>
	15	*
	16	* This program is free software; you can redistribute it and/or modify
	17	* it under the terms of the GNU General Public License version 2 as
	18	* published by the Free Software Foundation.
	19	*
	20	*/
	21
	22	#include <linux/module.h>
	23	#include <linux/kernel.h>
	24	#include <linux/init.h>
	25	#include <linux/slab.h>
	26	#include <linux/percpu.h>
	27	#include <linux/syscore_ops.h>
	28	#include <linux/rwsem.h>
fba14ae8	29	#include <linux/cpu.h>
f07fb521	30	#include "../leds.h"
8f88731d BW	31
	32	#define MAX_NAME_LEN 8
	33
	34	struct led_trigger_cpu {
	35	char name[MAX_NAME_LEN];
	36	struct led_trigger *_trig;
8f88731d BW	37	};
	38
	39	static DEFINE_PER_CPU(struct led_trigger_cpu, cpu_trig);
	40
	41	/**
	42	* ledtrig_cpu - emit a CPU event as a trigger
	43	* @evt: CPU event to be emitted
	44	*
	45	* Emit a CPU event on a CPU core, which will trigger a
	46	* binded LED to turn on or turn off.
	47	*/
	48	void ledtrig_cpu(enum cpu_led_event ledevt)
	49	{
	50	struct led_trigger_cpu *trig = &__get_cpu_var(cpu_trig);
	51
8f88731d BW	52	/* Locate the correct CPU LED */
	53	switch (ledevt) {
	54	case CPU_LED_IDLE_END:
	55	case CPU_LED_START:
	56	/* Will turn the LED on, max brightness */
	57	led_trigger_event(trig->_trig, LED_FULL);
	58	break;
	59
	60	case CPU_LED_IDLE_START:
	61	case CPU_LED_STOP:
	62	case CPU_LED_HALTED:
	63	/* Will turn the LED off */
	64	led_trigger_event(trig->_trig, LED_OFF);
	65	break;
	66
	67	default:
	68	/* Will leave the LED as it is */
	69	break;
	70	}
8f88731d BW	71	}
	72	EXPORT_SYMBOL(ledtrig_cpu);
	73
	74	static int ledtrig_cpu_syscore_suspend(void)
	75	{
	76	ledtrig_cpu(CPU_LED_STOP);
	77	return 0;
	78	}
	79
	80	static void ledtrig_cpu_syscore_resume(void)
	81	{
	82	ledtrig_cpu(CPU_LED_START);
	83	}
	84
	85	static void ledtrig_cpu_syscore_shutdown(void)
	86	{
	87	ledtrig_cpu(CPU_LED_HALTED);
	88	}
	89
	90	static struct syscore_ops ledtrig_cpu_syscore_ops = {
	91	.shutdown = ledtrig_cpu_syscore_shutdown,
	92	.suspend = ledtrig_cpu_syscore_suspend,
	93	.resume = ledtrig_cpu_syscore_resume,
	94	};
	95
fba14ae8 PM	96	static int ledtrig_cpu_notify(struct notifier_block *self,
	97	unsigned long action, void *hcpu)
	98	{
	99	switch (action & ~CPU_TASKS_FROZEN) {
	100	case CPU_STARTING:
	101	ledtrig_cpu(CPU_LED_START);
	102	break;
	103	case CPU_DYING:
	104	ledtrig_cpu(CPU_LED_STOP);
	105	break;
	106	}
	107
	108	return NOTIFY_OK;
	109	}
	110
	111
	112	static struct notifier_block ledtrig_cpu_nb = {
	113	.notifier_call = ledtrig_cpu_notify,
	114	};
	115
8f88731d BW	116	static int __init ledtrig_cpu_init(void)
	117	{
	118	int cpu;
	119
	120	/* Supports up to 9999 cpu cores */
	121	BUILD_BUG_ON(CONFIG_NR_CPUS > 9999);
	122
	123	/*
	124	* Registering CPU led trigger for each CPU core here
	125	* ignores CPU hotplug, but after this CPU hotplug works
	126	* fine with this trigger.
	127	*/
	128	for_each_possible_cpu(cpu) {
	129	struct led_trigger_cpu *trig = &per_cpu(cpu_trig, cpu);
	130
8f88731d BW	131	snprintf(trig->name, MAX_NAME_LEN, "cpu%d", cpu);
8f88731d BW	132
8f88731d	133	led_trigger_register_simple(trig->name, &trig->_trig);
8f88731d BW	134	}
	135
	136	register_syscore_ops(&ledtrig_cpu_syscore_ops);
fba14ae8	137	register_cpu_notifier(&ledtrig_cpu_nb);
8f88731d BW	138
	139	pr_info("ledtrig-cpu: registered to indicate activity on CPUs\n");
	140
	141	return 0;
	142	}
	143	module_init(ledtrig_cpu_init);
	144
	145	static void __exit ledtrig_cpu_exit(void)
	146	{
	147	int cpu;
	148
fba14ae8 PM	149	unregister_cpu_notifier(&ledtrig_cpu_nb);
fba14ae8 PM	150
8f88731d BW	151	for_each_possible_cpu(cpu) {
	152	struct led_trigger_cpu *trig = &per_cpu(cpu_trig, cpu);
	153
8f88731d BW	154	led_trigger_unregister_simple(trig->_trig);
	155	trig->_trig = NULL;
	156	memset(trig->name, 0, MAX_NAME_LEN);
8f88731d BW	157	}
	158
	159	unregister_syscore_ops(&ledtrig_cpu_syscore_ops);
	160	}
	161	module_exit(ledtrig_cpu_exit);
	162
	163	MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");
	164	MODULE_AUTHOR("Bryan Wu <bryan.wu@canonical.com>");
	165	MODULE_DESCRIPTION("CPU LED trigger");
	166	MODULE_LICENSE("GPL");