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/ctype.h>
  13 #include <linux/device.h>
  14 #include <linux/err.h>
  15 #include <linux/init.h>
  16 #include <linux/kernel.h>
  17 #include <linux/leds.h>
  18 #include <linux/list.h>
  19 #include <linux/module.h>
  20 #include <linux/slab.h>
  21 #include <linux/spinlock.h>
  22 #include <linux/timer.h>
  23 #include "leds.h"
  24
  25 static struct class *leds_class;
  26
  27 static ssize_t brightness_show(struct device *dev,
  28                 struct device_attribute *attr, char *buf)
  29 {
  30         struct led_classdev *led_cdev = dev_get_drvdata(dev);
  31
  32         /* no lock needed for this */
  33         led_update_brightness(led_cdev);
  34
  35         return sprintf(buf, "%u\n", led_cdev->brightness);
  36 }
  37
  38 static ssize_t brightness_store(struct device *dev,
  39                 struct device_attribute *attr, const char *buf, size_t size)
  40 {
  41         struct led_classdev *led_cdev = dev_get_drvdata(dev);
  42         unsigned long state;
  43         ssize_t ret;
  44
  45         mutex_lock(&led_cdev->led_access);
  46
  47         if (led_sysfs_is_disabled(led_cdev)) {
  48                 ret = -EBUSY;
  49                 goto unlock;
  50         }
  51
  52         ret = kstrtoul(buf, 10, &state);
  53         if (ret)
  54                 goto unlock;
  55
  56         if (state == LED_OFF)
  57                 led_trigger_remove(led_cdev);
  58         led_set_brightness(led_cdev, state);
  59
  60         ret = size;
  61 unlock:
  62         mutex_unlock(&led_cdev->led_access);
  63         return ret;
  64 }
  65 static DEVICE_ATTR_RW(brightness);
  66
  67 static ssize_t 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 static DEVICE_ATTR_RO(max_brightness);
  75
  76 #ifdef CONFIG_LEDS_TRIGGERS
  77 static DEVICE_ATTR(trigger, 0644, led_trigger_show, led_trigger_store);
  78 static struct attribute *led_trigger_attrs[] = {
  79         &dev_attr_trigger.attr,
  80         NULL,
  81 };
  82 static const struct attribute_group led_trigger_group = {
  83         .attrs = led_trigger_attrs,
  84 };
  85 #endif
  86
  87 static struct attribute *led_class_attrs[] = {
  88         &dev_attr_brightness.attr,
  89         &dev_attr_max_brightness.attr,
  90         NULL,
  91 };
  92
  93 static const struct attribute_group led_group = {
  94         .attrs = led_class_attrs,
  95 };
  96
  97 static const struct attribute_group *led_groups[] = {
  98         &led_group,
  99 #ifdef CONFIG_LEDS_TRIGGERS
 100         &led_trigger_group,
 101 #endif
 102         NULL,
 103 };
 104
 105 /**
 106  * led_classdev_suspend - suspend an led_classdev.
 107  * @led_cdev: the led_classdev to suspend.
 108  */
 109 void led_classdev_suspend(struct led_classdev *led_cdev)
 110 {
 111         led_cdev->flags |= LED_SUSPENDED;
 112         led_set_brightness_nopm(led_cdev, 0);
 113         flush_work(&led_cdev->set_brightness_work);
 114 }
 115 EXPORT_SYMBOL_GPL(led_classdev_suspend);
 116
 117 /**
 118  * led_classdev_resume - resume an led_classdev.
 119  * @led_cdev: the led_classdev to resume.
 120  */
 121 void led_classdev_resume(struct led_classdev *led_cdev)
 122 {
 123         led_set_brightness_nopm(led_cdev, led_cdev->brightness);
 124
 125         if (led_cdev->flash_resume)
 126                 led_cdev->flash_resume(led_cdev);
 127
 128         led_cdev->flags &= ~LED_SUSPENDED;
 129 }
 130 EXPORT_SYMBOL_GPL(led_classdev_resume);
 131
 132 #ifdef CONFIG_PM_SLEEP
 133 static int led_suspend(struct device *dev)
 134 {
 135         struct led_classdev *led_cdev = dev_get_drvdata(dev);
 136
 137         if (led_cdev->flags & LED_CORE_SUSPENDRESUME)
 138                 led_classdev_suspend(led_cdev);
 139
 140         return 0;
 141 }
 142
 143 static int led_resume(struct device *dev)
 144 {
 145         struct led_classdev *led_cdev = dev_get_drvdata(dev);
 146
 147         if (led_cdev->flags & LED_CORE_SUSPENDRESUME)
 148                 led_classdev_resume(led_cdev);
 149
 150         return 0;
 151 }
 152 #endif
 153
 154 static SIMPLE_DEV_PM_OPS(leds_class_dev_pm_ops, led_suspend, led_resume);
 155
 156 static int match_name(struct device *dev, const void *data)
 157 {
 158         if (!dev_name(dev))
 159                 return 0;
 160         return !strcmp(dev_name(dev), (char *)data);
 161 }
 162
 163 static int led_classdev_next_name(const char *init_name, char *name,
 164                                   size_t len)
 165 {
 166         unsigned int i = 0;
 167         int ret = 0;
 168         struct device *dev;
 169
 170         strlcpy(name, init_name, len);
 171
 172         while ((ret < len) &&
 173                (dev = class_find_device(leds_class, NULL, name, match_name))) {
 174                 put_device(dev);
 175                 ret = snprintf(name, len, "%s_%u", init_name, ++i);
 176         }
 177
 178         if (ret >= len)
 179                 return -ENOMEM;
 180
 181         return i;
 182 }
 183
 184 /**
 185  * led_classdev_register - register a new object of led_classdev class.
 186  * @parent: The device to register.
 187  * @led_cdev: the led_classdev structure for this device.
 188  */
 189 int led_classdev_register(struct device *parent, struct led_classdev *led_cdev)
 190 {
 191         char name[64];
 192         int ret;
 193
 194         ret = led_classdev_next_name(led_cdev->name, name, sizeof(name));
 195         if (ret < 0)
 196                 return ret;
 197
 198         led_cdev->dev = device_create_with_groups(leds_class, parent, 0,
 199                                 led_cdev, led_cdev->groups, "%s", name);
 200         if (IS_ERR(led_cdev->dev))
 201                 return PTR_ERR(led_cdev->dev);
 202
 203         if (ret)
 204                 dev_warn(parent, "Led %s renamed to %s due to name collision",
 205                                 led_cdev->name, dev_name(led_cdev->dev));
 206
 207 #ifdef CONFIG_LEDS_TRIGGERS
 208         init_rwsem(&led_cdev->trigger_lock);
 209 #endif
 210         mutex_init(&led_cdev->led_access);
 211         /* add to the list of leds */
 212         down_write(&leds_list_lock);
 213         list_add_tail(&led_cdev->node, &leds_list);
 214         up_write(&leds_list_lock);
 215
 216         if (!led_cdev->max_brightness)
 217                 led_cdev->max_brightness = LED_FULL;
 218
 219         led_update_brightness(led_cdev);
 220
 221         led_init_core(led_cdev);
 222
 223 #ifdef CONFIG_LEDS_TRIGGERS
 224         led_trigger_set_default(led_cdev);
 225 #endif
 226
 227         dev_dbg(parent, "Registered led device: %s\n",
 228                         led_cdev->name);
 229
 230         return 0;
 231 }
 232 EXPORT_SYMBOL_GPL(led_classdev_register);
 233
 234 /**
 235  * led_classdev_unregister - unregisters a object of led_properties class.
 236  * @led_cdev: the led device to unregister
 237  *
 238  * Unregisters a previously registered via led_classdev_register object.
 239  */
 240 void led_classdev_unregister(struct led_classdev *led_cdev)
 241 {
 242 #ifdef CONFIG_LEDS_TRIGGERS
 243         down_write(&led_cdev->trigger_lock);
 244         if (led_cdev->trigger)
 245                 led_trigger_set(led_cdev, NULL);
 246         up_write(&led_cdev->trigger_lock);
 247 #endif
 248
 249         led_cdev->flags |= LED_UNREGISTERING;
 250
 251         /* Stop blinking */
 252         led_stop_software_blink(led_cdev);
 253
 254         led_set_brightness(led_cdev, LED_OFF);
 255
 256         flush_work(&led_cdev->set_brightness_work);
 257
 258         device_unregister(led_cdev->dev);
 259
 260         down_write(&leds_list_lock);
 261         list_del(&led_cdev->node);
 262         up_write(&leds_list_lock);
 263
 264         mutex_destroy(&led_cdev->led_access);
 265 }
 266 EXPORT_SYMBOL_GPL(led_classdev_unregister);
 267
 268 static void devm_led_classdev_release(struct device *dev, void *res)
 269 {
 270         led_classdev_unregister(*(struct led_classdev **)res);
 271 }
 272
 273 /**
 274  * devm_led_classdev_register - resource managed led_classdev_register()
 275  * @parent: The device to register.
 276  * @led_cdev: the led_classdev structure for this device.
 277  */
 278 int devm_led_classdev_register(struct device *parent,
 279                                struct led_classdev *led_cdev)
 280 {
 281         struct led_classdev **dr;
 282         int rc;
 283
 284         dr = devres_alloc(devm_led_classdev_release, sizeof(*dr), GFP_KERNEL);
 285         if (!dr)
 286                 return -ENOMEM;
 287
 288         rc = led_classdev_register(parent, led_cdev);
 289         if (rc) {
 290                 devres_free(dr);
 291                 return rc;
 292         }
 293
 294         *dr = led_cdev;
 295         devres_add(parent, dr);
 296
 297         return 0;
 298 }
 299 EXPORT_SYMBOL_GPL(devm_led_classdev_register);
 300
 301 static int devm_led_classdev_match(struct device *dev, void *res, void *data)
 302 {
 303         struct led_cdev **p = res;
 304
 305         if (WARN_ON(!p || !*p))
 306                 return 0;
 307
 308         return *p == data;
 309 }
 310
 311 /**
 312  * devm_led_classdev_unregister() - resource managed led_classdev_unregister()
 313  * @parent: The device to unregister.
 314  * @led_cdev: the led_classdev structure for this device.
 315  */
 316 void devm_led_classdev_unregister(struct device *dev,
 317                                   struct led_classdev *led_cdev)
 318 {
 319         WARN_ON(devres_release(dev,
 320                                devm_led_classdev_release,
 321                                devm_led_classdev_match, led_cdev));
 322 }
 323 EXPORT_SYMBOL_GPL(devm_led_classdev_unregister);
 324
 325 static int __init leds_init(void)
 326 {
 327         leds_class = class_create(THIS_MODULE, "leds");
 328         if (IS_ERR(leds_class))
 329                 return PTR_ERR(leds_class);
 330         leds_class->pm = &leds_class_dev_pm_ops;
 331         leds_class->dev_groups = led_groups;
 332         return 0;
 333 }
 334
 335 static void __exit leds_exit(void)
 336 {
 337         class_destroy(leds_class);
 338 }
 339
 340 subsys_initcall(leds_init);
 341 module_exit(leds_exit);
 342
 343 MODULE_AUTHOR("John Lenz, Richard Purdie");
 344 MODULE_LICENSE("GPL");
 345 MODULE_DESCRIPTION("LED Class Interface");