blob: 4239b3955ff08f27edacbc4311bb09f93231bd69 [file] [log] [blame]
Bryan Wu8f887312011-06-25 18:33:50 +08001/*
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
33struct led_trigger_cpu {
34 char name[MAX_NAME_LEN];
35 struct led_trigger *_trig;
Bryan Wu8f887312011-06-25 18:33:50 +080036};
37
38static 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 */
47void ledtrig_cpu(enum cpu_led_event ledevt)
48{
49 struct led_trigger_cpu *trig = &__get_cpu_var(cpu_trig);
50
Bryan Wu8f887312011-06-25 18:33:50 +080051 /* 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 }
Bryan Wu8f887312011-06-25 18:33:50 +080070}
71EXPORT_SYMBOL(ledtrig_cpu);
72
73static int ledtrig_cpu_syscore_suspend(void)
74{
75 ledtrig_cpu(CPU_LED_STOP);
76 return 0;
77}
78
79static void ledtrig_cpu_syscore_resume(void)
80{
81 ledtrig_cpu(CPU_LED_START);
82}
83
84static void ledtrig_cpu_syscore_shutdown(void)
85{
86 ledtrig_cpu(CPU_LED_HALTED);
87}
88
89static 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
95static 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
Bryan Wu8f887312011-06-25 18:33:50 +0800110 snprintf(trig->name, MAX_NAME_LEN, "cpu%d", cpu);
111
Bryan Wu8f887312011-06-25 18:33:50 +0800112 led_trigger_register_simple(trig->name, &trig->_trig);
Bryan Wu8f887312011-06-25 18:33:50 +0800113 }
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}
121module_init(ledtrig_cpu_init);
122
123static 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
Bryan Wu8f887312011-06-25 18:33:50 +0800130 led_trigger_unregister_simple(trig->_trig);
131 trig->_trig = NULL;
132 memset(trig->name, 0, MAX_NAME_LEN);
Bryan Wu8f887312011-06-25 18:33:50 +0800133 }
134
135 unregister_syscore_ops(&ledtrig_cpu_syscore_ops);
136}
137module_exit(ledtrig_cpu_exit);
138
139MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");
140MODULE_AUTHOR("Bryan Wu <bryan.wu@canonical.com>");
141MODULE_DESCRIPTION("CPU LED trigger");
142MODULE_LICENSE("GPL");