drivers/leds/led-class.c

   1 /*
   2  * LED Class Core
   3  *
   4  * Copyright (C) 2005 John Lenz <lenz@cs.wisc.edu>
   5  * Copyright (C) 2005-2007 Richard Purdie <rpurdie@openedhand.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11
  12 #include <linux/module.h>
  13 #include <linux/kernel.h>
  14 #include <linux/init.h>
  15 #include <linux/list.h>
  16 #include <linux/spinlock.h>
  17 #include <linux/device.h>
  18 #include <linux/sysdev.h>
  19 #include <linux/timer.h>
  20 #include <linux/err.h>
  21 #include <linux/ctype.h>
  22 #include <linux/leds.h>
  23 #include "leds.h"
  24
  25 static struct class *leds_class;
  26
  27 static void led_update_brightness(struct led_classdev *led_cdev)
  28 {
  29         if (led_cdev->brightness_get)
  30                 led_cdev->brightness = led_cdev->brightness_get(led_cdev);
  31 }
  32
  33 static ssize_t led_brightness_show(struct device *dev,
  34                 struct device_attribute *attr, char *buf)
  35 {
  36         struct led_classdev *led_cdev = dev_get_drvdata(dev);
  37
  38         /* no lock needed for this */
  39         led_update_brightness(led_cdev);
  40
  41         return sprintf(buf, "%u\n", led_cdev->brightness);
  42 }
  43
  44 static ssize_t led_brightness_store(struct device *dev,
  45                 struct device_attribute *attr, const char *buf, size_t size)
  46 {
  47         struct led_classdev *led_cdev = dev_get_drvdata(dev);
  48         ssize_t ret = -EINVAL;
  49         char *after;
  50         unsigned long state = simple_strtoul(buf, &after, 10);
  51         size_t count = after - buf;
  52
  53         if (*after && isspace(*after))
  54                 count++;
  55
  56         if (count == size) {
  57                 ret = count;
  58
  59                 if (state == LED_OFF)
  60                         led_trigger_remove(led_cdev);
  61                 led_set_brightness(led_cdev, state);
  62         }
  63
  64         return ret;
  65 }
  66
  67 static ssize_t led_max_brightness_show(struct device *dev,
  68                 struct device_attribute *attr, char *buf)
  69 {
  70         struct led_classdev *led_cdev = dev_get_drvdata(dev);
  71
  72         return sprintf(buf, "%u\n", led_cdev->max_brightness);
  73 }
  74
  75 static DEVICE_ATTR(brightness, 0644, led_brightness_show, led_brightness_store);
  76 static DEVICE_ATTR(max_brightness, 0444, led_max_brightness_show, NULL);
  77 #ifdef CONFIG_LEDS_TRIGGERS
  78 static DEVICE_ATTR(trigger, 0644, led_trigger_show, led_trigger_store);
  79 #endif
  80
  81 /**
  82  * led_classdev_suspend - suspend an led_classdev.
  83  * @led_cdev: the led_classdev to suspend.
  84  */
  85 void led_classdev_suspend(struct led_classdev *led_cdev)
  86 {
  87         led_cdev->flags |= LED_SUSPENDED;
  88         led_cdev->brightness_set(led_cdev, 0);
  89 }
  90 EXPORT_SYMBOL_GPL(led_classdev_suspend);
  91
  92 /**
  93  * led_classdev_resume - resume an led_classdev.
  94  * @led_cdev: the led_classdev to resume.
  95  */
  96 void led_classdev_resume(struct led_classdev *led_cdev)
  97 {
  98         led_cdev->brightness_set(led_cdev, led_cdev->brightness);
  99         led_cdev->flags &= ~LED_SUSPENDED;
 100 }
 101 EXPORT_SYMBOL_GPL(led_classdev_resume);
 102
 103 static int led_suspend(struct device *dev, pm_message_t state)
 104 {
 105         struct led_classdev *led_cdev = dev_get_drvdata(dev);
 106
 107         if (led_cdev->flags & LED_CORE_SUSPENDRESUME)
 108                 led_classdev_suspend(led_cdev);
 109
 110         return 0;
 111 }
 112
 113 static int led_resume(struct device *dev)
 114 {
 115         struct led_classdev *led_cdev = dev_get_drvdata(dev);
 116
 117         if (led_cdev->flags & LED_CORE_SUSPENDRESUME)
 118                 led_classdev_resume(led_cdev);
 119
 120         return 0;
 121 }
 122
 123 /**
 124  * led_classdev_register - register a new object of led_classdev class.
 125  * @parent: The device to register.
 126  * @led_cdev: the led_classdev structure for this device.
 127  */
 128 int led_classdev_register(struct device *parent, struct led_classdev *led_cdev)
 129 {
 130         int rc;
 131
 132         led_cdev->dev = device_create(leds_class, parent, 0, led_cdev,
 133                                       "%s", led_cdev->name);
 134         if (IS_ERR(led_cdev->dev))
 135                 return PTR_ERR(led_cdev->dev);
 136
 137         /* register the attributes */
 138         rc = device_create_file(led_cdev->dev, &dev_attr_brightness);
 139         if (rc)
 140                 goto err_out;
 141
 142 #ifdef CONFIG_LEDS_TRIGGERS
 143         init_rwsem(&led_cdev->trigger_lock);
 144 #endif
 145         /* add to the list of leds */
 146         down_write(&leds_list_lock);
 147         list_add_tail(&led_cdev->node, &leds_list);
 148         up_write(&leds_list_lock);
 149
 150         if (!led_cdev->max_brightness)
 151                 led_cdev->max_brightness = LED_FULL;
 152
 153         rc = device_create_file(led_cdev->dev, &dev_attr_max_brightness);
 154         if (rc)
 155                 goto err_out_attr_max;
 156
 157         led_update_brightness(led_cdev);
 158
 159 #ifdef CONFIG_LEDS_TRIGGERS
 160         rc = device_create_file(led_cdev->dev, &dev_attr_trigger);
 161         if (rc)
 162                 goto err_out_led_list;
 163
 164         led_trigger_set_default(led_cdev);
 165 #endif
 166
 167         printk(KERN_INFO "Registered led device: %s\n",
 168                         led_cdev->name);
 169
 170         return 0;
 171
 172 #ifdef CONFIG_LEDS_TRIGGERS
 173 err_out_led_list:
 174         device_remove_file(led_cdev->dev, &dev_attr_max_brightness);
 175 #endif
 176 err_out_attr_max:
 177         device_remove_file(led_cdev->dev, &dev_attr_brightness);
 178         list_del(&led_cdev->node);
 179 err_out:
 180         device_unregister(led_cdev->dev);
 181         return rc;
 182 }
 183 EXPORT_SYMBOL_GPL(led_classdev_register);
 184
 185 /**
 186  * led_classdev_unregister - unregisters a object of led_properties class.
 187  * @led_cdev: the led device to unregister
 188  *
 189  * Unregisters a previously registered via led_classdev_register object.
 190  */
 191 void led_classdev_unregister(struct led_classdev *led_cdev)
 192 {
 193         device_remove_file(led_cdev->dev, &dev_attr_max_brightness);
 194         device_remove_file(led_cdev->dev, &dev_attr_brightness);
 195 #ifdef CONFIG_LEDS_TRIGGERS
 196         device_remove_file(led_cdev->dev, &dev_attr_trigger);
 197         down_write(&led_cdev->trigger_lock);
 198         if (led_cdev->trigger)
 199                 led_trigger_set(led_cdev, NULL);
 200         up_write(&led_cdev->trigger_lock);
 201 #endif
 202
 203         device_unregister(led_cdev->dev);
 204
 205         down_write(&leds_list_lock);
 206         list_del(&led_cdev->node);
 207         up_write(&leds_list_lock);
 208 }
 209 EXPORT_SYMBOL_GPL(led_classdev_unregister);
 210
 211 static int __init leds_init(void)
 212 {
 213         leds_class = class_create(THIS_MODULE, "leds");
 214         if (IS_ERR(leds_class))
 215                 return PTR_ERR(leds_class);
 216         leds_class->suspend = led_suspend;
 217         leds_class->resume = led_resume;
 218         return 0;
 219 }
 220
 221 static void __exit leds_exit(void)
 222 {
 223         class_destroy(leds_class);
 224 }
 225
 226 subsys_initcall(leds_init);
 227 module_exit(leds_exit);
 228
 229 MODULE_AUTHOR("John Lenz, Richard Purdie");
 230 MODULE_LICENSE("GPL");
 231 MODULE_DESCRIPTION("LED Class Interface");