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_cdev->brightness_set(led_cdev, 0);
 113 }
 114 EXPORT_SYMBOL_GPL(led_classdev_suspend);
 115
 116 /**
 117  * led_classdev_resume - resume an led_classdev.
 118  * @led_cdev: the led_classdev to resume.
 119  */
 120 void led_classdev_resume(struct led_classdev *led_cdev)
 121 {
 122         led_cdev->brightness_set(led_cdev, led_cdev->brightness);
 123
 124         if (led_cdev->flash_resume)
 125                 led_cdev->flash_resume(led_cdev);
 126
 127         led_cdev->flags &= ~LED_SUSPENDED;
 128 }
 129 EXPORT_SYMBOL_GPL(led_classdev_resume);
 130
 131 #ifdef CONFIG_PM_SLEEP
 132 static int led_suspend(struct device *dev)
 133 {
 134         struct led_classdev *led_cdev = dev_get_drvdata(dev);
 135
 136         if (led_cdev->flags & LED_CORE_SUSPENDRESUME)
 137                 led_classdev_suspend(led_cdev);
 138
 139         return 0;
 140 }
 141
 142 static int led_resume(struct device *dev)
 143 {
 144         struct led_classdev *led_cdev = dev_get_drvdata(dev);
 145
 146         if (led_cdev->flags & LED_CORE_SUSPENDRESUME)
 147                 led_classdev_resume(led_cdev);
 148
 149         return 0;
 150 }
 151 #endif
 152
 153 static SIMPLE_DEV_PM_OPS(leds_class_dev_pm_ops, led_suspend, led_resume);
 154
 155 static int match_name(struct device *dev, const void *data)
 156 {
 157         if (!dev_name(dev))
 158                 return 0;
 159         return !strcmp(dev_name(dev), (char *)data);
 160 }
 161
 162 static int led_classdev_next_name(const char *init_name, char *name,
 163                                   size_t len)
 164 {
 165         unsigned int i = 0;
 166         int ret = 0;
 167         struct device *dev;
 168
 169         strlcpy(name, init_name, len);
 170
 171         while ((ret < len) &&
 172                (dev = class_find_device(leds_class, NULL, name, match_name))) {
 173                 put_device(dev);
 174                 ret = snprintf(name, len, "%s_%u", init_name, ++i);
 175         }
 176
 177         if (ret >= len)
 178                 return -ENOMEM;
 179
 180         return i;
 181 }
 182
 183 /**
 184  * led_classdev_register - register a new object of led_classdev class.
 185  * @parent: The device to register.
 186  * @led_cdev: the led_classdev structure for this device.
 187  */
 188 int led_classdev_register(struct device *parent, struct led_classdev *led_cdev)
 189 {
 190         char name[64];
 191         int ret;
 192
 193         ret = led_classdev_next_name(led_cdev->name, name, sizeof(name));
 194         if (ret < 0)
 195                 return ret;
 196
 197         led_cdev->dev = device_create_with_groups(leds_class, parent, 0,
 198                                 led_cdev, led_cdev->groups, "%s", name);
 199         if (IS_ERR(led_cdev->dev))
 200                 return PTR_ERR(led_cdev->dev);
 201
 202         if (ret)
 203                 dev_warn(parent, "Led %s renamed to %s due to name collision",
 204                                 led_cdev->name, dev_name(led_cdev->dev));
 205
 206 #ifdef CONFIG_LEDS_TRIGGERS
 207         init_rwsem(&led_cdev->trigger_lock);
 208 #endif
 209         mutex_init(&led_cdev->led_access);
 210         /* add to the list of leds */
 211         down_write(&leds_list_lock);
 212         list_add_tail(&led_cdev->node, &leds_list);
 213         up_write(&leds_list_lock);
 214
 215         if (!led_cdev->max_brightness)
 216                 led_cdev->max_brightness = LED_FULL;
 217
 218         led_cdev->flags |= SET_BRIGHTNESS_ASYNC;
 219
 220         led_update_brightness(led_cdev);
 221
 222         led_init_core(led_cdev);
 223
 224 #ifdef CONFIG_LEDS_TRIGGERS
 225         led_trigger_set_default(led_cdev);
 226 #endif
 227
 228         dev_dbg(parent, "Registered led device: %s\n",
 229                         led_cdev->name);
 230
 231         return 0;
 232 }
 233 EXPORT_SYMBOL_GPL(led_classdev_register);
 234
 235 /**
 236  * led_classdev_unregister - unregisters a object of led_properties class.
 237  * @led_cdev: the led device to unregister
 238  *
 239  * Unregisters a previously registered via led_classdev_register object.
 240  */
 241 void led_classdev_unregister(struct led_classdev *led_cdev)
 242 {
 243 #ifdef CONFIG_LEDS_TRIGGERS
 244         down_write(&led_cdev->trigger_lock);
 245         if (led_cdev->trigger)
 246                 led_trigger_set(led_cdev, NULL);
 247         up_write(&led_cdev->trigger_lock);
 248 #endif
 249
 250         cancel_work_sync(&led_cdev->set_brightness_work);
 251
 252         /* Stop blinking */
 253         led_stop_software_blink(led_cdev);
 254         led_set_brightness(led_cdev, LED_OFF);
 255
 256         device_unregister(led_cdev->dev);
 257
 258         down_write(&leds_list_lock);
 259         list_del(&led_cdev->node);
 260         up_write(&leds_list_lock);
 261
 262         mutex_destroy(&led_cdev->led_access);
 263 }
 264 EXPORT_SYMBOL_GPL(led_classdev_unregister);
 265
 266 static void devm_led_classdev_release(struct device *dev, void *res)
 267 {
 268         led_classdev_unregister(*(struct led_classdev **)res);
 269 }
 270
 271 /**
 272  * devm_led_classdev_register - resource managed led_classdev_register()
 273  * @parent: The device to register.
 274  * @led_cdev: the led_classdev structure for this device.
 275  */
 276 int devm_led_classdev_register(struct device *parent,
 277                                struct led_classdev *led_cdev)
 278 {
 279         struct led_classdev **dr;
 280         int rc;
 281
 282         dr = devres_alloc(devm_led_classdev_release, sizeof(*dr), GFP_KERNEL);
 283         if (!dr)
 284                 return -ENOMEM;
 285
 286         rc = led_classdev_register(parent, led_cdev);
 287         if (rc) {
 288                 devres_free(dr);
 289                 return rc;
 290         }
 291
 292         *dr = led_cdev;
 293         devres_add(parent, dr);
 294
 295         return 0;
 296 }
 297 EXPORT_SYMBOL_GPL(devm_led_classdev_register);
 298
 299 static int devm_led_classdev_match(struct device *dev, void *res, void *data)
 300 {
 301         struct led_cdev **p = res;
 302
 303         if (WARN_ON(!p || !*p))
 304                 return 0;
 305
 306         return *p == data;
 307 }
 308
 309 /**
 310  * devm_led_classdev_unregister() - resource managed led_classdev_unregister()
 311  * @parent: The device to unregister.
 312  * @led_cdev: the led_classdev structure for this device.
 313  */
 314 void devm_led_classdev_unregister(struct device *dev,
 315                                   struct led_classdev *led_cdev)
 316 {
 317         WARN_ON(devres_release(dev,
 318                                devm_led_classdev_release,
 319                                devm_led_classdev_match, led_cdev));
 320 }
 321 EXPORT_SYMBOL_GPL(devm_led_classdev_unregister);
 322
 323 static int __init leds_init(void)
 324 {
 325         leds_class = class_create(THIS_MODULE, "leds");
 326         if (IS_ERR(leds_class))
 327                 return PTR_ERR(leds_class);
 328         leds_class->pm = &leds_class_dev_pm_ops;
 329         leds_class->dev_groups = led_groups;
 330         return 0;
 331 }
 332
 333 static void __exit leds_exit(void)
 334 {
 335         class_destroy(leds_class);
 336 }
 337
 338 subsys_initcall(leds_init);
 339 module_exit(leds_exit);
 340
 341 MODULE_AUTHOR("John Lenz, Richard Purdie");
 342 MODULE_LICENSE("GPL");
 343 MODULE_DESCRIPTION("LED Class Interface");