| /* |
| * 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/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 = this_cpu_ptr(&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; |
| } |
| device_initcall(ledtrig_cpu_init); |