cregit-Linux how code gets into the kernel

Release 4.9 drivers/leds/trigger/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/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; } }

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EXPORT_SYMBOL(ledtrig_cpu);
static int ledtrig_cpu_syscore_suspend(void) { ledtrig_cpu(CPU_LED_STOP); return 0; }

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static void ledtrig_cpu_syscore_resume(void) { ledtrig_cpu(CPU_LED_START); }

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static void ledtrig_cpu_syscore_shutdown(void) { ledtrig_cpu(CPU_LED_HALTED); }

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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_online_cpu(unsigned int cpu) { ledtrig_cpu(CPU_LED_START); return 0; }

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static int ledtrig_prepare_down_cpu(unsigned int cpu) { ledtrig_cpu(CPU_LED_STOP); return 0; }

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Total18100.00%3100.00%


static int __init ledtrig_cpu_init(void) { int cpu; int ret; /* 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); ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "AP_LEDTRIG_STARTING", ledtrig_online_cpu, ledtrig_prepare_down_cpu); if (ret < 0) pr_err("CPU hotplug notifier for ledtrig-cpu could not be registered: %d\n", ret); pr_info("ledtrig-cpu: registered to indicate activity on CPUs\n"); return 0; }

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bryan wubryan wu7973.15%125.00%
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richard cochranrichard cochran54.63%125.00%
pawel mollpawel moll32.78%125.00%
Total108100.00%4100.00%

device_initcall(ledtrig_cpu_init);

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sebastian andrzej siewiorsebastian andrzej siewior236.76%114.29%
richard cochranrichard cochran205.88%114.29%
christoph lameterchristoph lameter20.59%114.29%
paul gortmakerpaul gortmaker10.29%114.29%
kim milokim milo10.29%114.29%
Total340100.00%7100.00%