Root/
| 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; |
| 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 | |
| 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 | } |
| 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 | |
| 110 | snprintf(trig->name, MAX_NAME_LEN, "cpu%d", cpu); |
| 111 | |
| 112 | led_trigger_register_simple(trig->name, &trig->_trig); |
| 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 | |
| 130 | led_trigger_unregister_simple(trig->_trig); |
| 131 | trig->_trig = NULL; |
| 132 | memset(trig->name, 0, MAX_NAME_LEN); |
| 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"); |
| 143 |
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