arch/arm/kernel/leds.c

   1 /*
   2  * LED support code, ripped out of arch/arm/kernel/time.c
   3  *
   4  *  Copyright (C) 1994-2001 Russell King
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10 #include <linux/export.h>
  11 #include <linux/init.h>
  12 #include <linux/device.h>
  13 #include <linux/syscore_ops.h>
  14 #include <linux/string.h>
  15
  16 #include <asm/leds.h>
  17
  18 static void dummy_leds_event(led_event_t evt)
  19 {
  20 }
  21
  22 void (*leds_event)(led_event_t) = dummy_leds_event;
  23
  24 struct leds_evt_name {
  25         const char      name[8];
  26         int             on;
  27         int             off;
  28 };
  29
  30 static const struct leds_evt_name evt_names[] = {
  31         { "amber", led_amber_on, led_amber_off },
  32         { "blue",  led_blue_on,  led_blue_off  },
  33         { "green", led_green_on, led_green_off },
  34         { "red",   led_red_on,   led_red_off   },
  35 };
  36
  37 static ssize_t leds_store(struct device *dev,
  38                         struct device_attribute *attr,
  39                         const char *buf, size_t size)
  40 {
  41         int ret = -EINVAL, len = strcspn(buf, " ");
  42
  43         if (len > 0 && buf[len] == '\0')
  44                 len--;
  45
  46         if (strncmp(buf, "claim", len) == 0) {
  47                 leds_event(led_claim);
  48                 ret = size;
  49         } else if (strncmp(buf, "release", len) == 0) {
  50                 leds_event(led_release);
  51                 ret = size;
  52         } else {
  53                 int i;
  54
  55                 for (i = 0; i < ARRAY_SIZE(evt_names); i++) {
  56                         if (strlen(evt_names[i].name) != len ||
  57                             strncmp(buf, evt_names[i].name, len) != 0)
  58                                 continue;
  59                         if (strncmp(buf+len, " on", 3) == 0) {
  60                                 leds_event(evt_names[i].on);
  61                                 ret = size;
  62                         } else if (strncmp(buf+len, " off", 4) == 0) {
  63                                 leds_event(evt_names[i].off);
  64                                 ret = size;
  65                         }
  66                         break;
  67                 }
  68         }
  69         return ret;
  70 }
  71
  72 static DEVICE_ATTR(event, 0200, NULL, leds_store);
  73
  74 static struct bus_type leds_subsys = {
  75         .name           = "leds",
  76         .dev_name       = "leds",
  77 };
  78
  79 static struct device leds_device = {
  80         .id             = 0,
  81         .bus            = &leds_subsys,
  82 };
  83
  84 static int leds_suspend(void)
  85 {
  86         leds_event(led_stop);
  87         return 0;
  88 }
  89
  90 static void leds_resume(void)
  91 {
  92         leds_event(led_start);
  93 }
  94
  95 static void leds_shutdown(void)
  96 {
  97         leds_event(led_halted);
  98 }
  99
 100 static struct syscore_ops leds_syscore_ops = {
 101         .shutdown       = leds_shutdown,
 102         .suspend        = leds_suspend,
 103         .resume         = leds_resume,
 104 };
 105
 106 static int __init leds_init(void)
 107 {
 108         int ret;
 109         ret = subsys_system_register(&leds_subsys, NULL);
 110         if (ret == 0)
 111                 ret = device_register(&leds_device);
 112         if (ret == 0)
 113                 ret = device_create_file(&leds_device, &dev_attr_event);
 114         if (ret == 0)
 115                 register_syscore_ops(&leds_syscore_ops);
 116         return ret;
 117 }
 118
 119 device_initcall(leds_init);
 120
 121 EXPORT_SYMBOL(leds_event);