ledtrig-cpu.rar_trigger

/* * 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");