[linux-2.6-block.git] / drivers / leds / 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 "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 __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);

	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;

	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>
	29	#include "leds.h"
	30
	31	#define MAX_NAME_LEN 8
	32
	33	struct led_trigger_cpu {
	34	char name[MAX_NAME_LEN];
	35	struct led_trigger *_trig;
8f88731d BW	36	};
	37
	38	static DEFINE_PER_CPU(struct led_trigger_cpu, cpu_trig);
	39
	40	/**
	41	* ledtrig_cpu - emit a CPU event as a trigger
	42	* @evt: CPU event to be emitted
	43	*
	44	* Emit a CPU event on a CPU core, which will trigger a
	45	* binded LED to turn on or turn off.
	46	*/
	47	void ledtrig_cpu(enum cpu_led_event ledevt)
	48	{
	49	struct led_trigger_cpu *trig = &__get_cpu_var(cpu_trig);
	50
8f88731d BW	51	/* Locate the correct CPU LED */
	52	switch (ledevt) {
	53	case CPU_LED_IDLE_END:
	54	case CPU_LED_START:
	55	/* Will turn the LED on, max brightness */
	56	led_trigger_event(trig->_trig, LED_FULL);
	57	break;
	58
	59	case CPU_LED_IDLE_START:
	60	case CPU_LED_STOP:
	61	case CPU_LED_HALTED:
	62	/* Will turn the LED off */
	63	led_trigger_event(trig->_trig, LED_OFF);
	64	break;
	65
	66	default:
	67	/* Will leave the LED as it is */
	68	break;
	69	}
8f88731d BW	70	}
	71	EXPORT_SYMBOL(ledtrig_cpu);
	72
	73	static int ledtrig_cpu_syscore_suspend(void)
	74	{
	75	ledtrig_cpu(CPU_LED_STOP);
	76	return 0;
	77	}
	78
	79	static void ledtrig_cpu_syscore_resume(void)
	80	{
	81	ledtrig_cpu(CPU_LED_START);
	82	}
	83
	84	static void ledtrig_cpu_syscore_shutdown(void)
	85	{
	86	ledtrig_cpu(CPU_LED_HALTED);
	87	}
	88
	89	static struct syscore_ops ledtrig_cpu_syscore_ops = {
	90	.shutdown = ledtrig_cpu_syscore_shutdown,
	91	.suspend = ledtrig_cpu_syscore_suspend,
	92	.resume = ledtrig_cpu_syscore_resume,
	93	};
	94
	95	static int __init ledtrig_cpu_init(void)
	96	{
	97	int cpu;
	98
	99	/* Supports up to 9999 cpu cores */
	100	BUILD_BUG_ON(CONFIG_NR_CPUS > 9999);
	101
	102	/*
	103	* Registering CPU led trigger for each CPU core here
	104	* ignores CPU hotplug, but after this CPU hotplug works
	105	* fine with this trigger.
	106	*/
	107	for_each_possible_cpu(cpu) {
	108	struct led_trigger_cpu *trig = &per_cpu(cpu_trig, cpu);
	109
8f88731d BW	110	snprintf(trig->name, MAX_NAME_LEN, "cpu%d", cpu);
8f88731d BW	111
8f88731d	112	led_trigger_register_simple(trig->name, &trig->_trig);
8f88731d BW	113	}
	114
	115	register_syscore_ops(&ledtrig_cpu_syscore_ops);
	116
	117	pr_info("ledtrig-cpu: registered to indicate activity on CPUs\n");
	118
	119	return 0;
	120	}
	121	module_init(ledtrig_cpu_init);
	122
	123	static void __exit ledtrig_cpu_exit(void)
	124	{
	125	int cpu;
	126
	127	for_each_possible_cpu(cpu) {
	128	struct led_trigger_cpu *trig = &per_cpu(cpu_trig, cpu);
	129
8f88731d BW	130	led_trigger_unregister_simple(trig->_trig);
	131	trig->_trig = NULL;
	132	memset(trig->name, 0, MAX_NAME_LEN);
8f88731d BW	133	}
	134
	135	unregister_syscore_ops(&ledtrig_cpu_syscore_ops);
	136	}
	137	module_exit(ledtrig_cpu_exit);
	138
	139	MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");
	140	MODULE_AUTHOR("Bryan Wu <bryan.wu@canonical.com>");
	141	MODULE_DESCRIPTION("CPU LED trigger");
	142	MODULE_LICENSE("GPL");