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 <uapi/linux/uleds.h>
  24 #include "leds.h"
  25
  26 static struct class *leds_class;
  27
  28 static ssize_t brightness_show(struct device *dev,
  29                 struct device_attribute *attr, char *buf)
  30 {
  31         struct led_classdev *led_cdev = dev_get_drvdata(dev);
  32
  33         /* no lock needed for this */
  34         led_update_brightness(led_cdev);
  35
  36         return sprintf(buf, "%u\n", led_cdev->brightness);
  37 }
  38
  39 static ssize_t brightness_store(struct device *dev,
  40                 struct device_attribute *attr, const char *buf, size_t size)
  41 {
  42         struct led_classdev *led_cdev = dev_get_drvdata(dev);
  43         unsigned long state;
  44         ssize_t ret;
  45
  46         mutex_lock(&led_cdev->led_access);
  47
  48         if (led_sysfs_is_disabled(led_cdev)) {
  49                 ret = -EBUSY;
  50                 goto unlock;
  51         }
  52
  53         ret = kstrtoul(buf, 10, &state);
  54         if (ret)
  55                 goto unlock;
  56
  57         if (state == LED_OFF)
  58                 led_trigger_remove(led_cdev);
  59         led_set_brightness(led_cdev, state);
  60
  61         ret = size;
  62 unlock:
  63         mutex_unlock(&led_cdev->led_access);
  64         return ret;
  65 }
  66 static DEVICE_ATTR_RW(brightness);
  67
  68 static ssize_t max_brightness_show(struct device *dev,
  69                 struct device_attribute *attr, char *buf)
  70 {
  71         struct led_classdev *led_cdev = dev_get_drvdata(dev);
  72
  73         return sprintf(buf, "%u\n", led_cdev->max_brightness);
  74 }
  75 static DEVICE_ATTR_RO(max_brightness);
  76
  77 #ifdef CONFIG_LEDS_TRIGGERS
  78 static DEVICE_ATTR(trigger, 0644, led_trigger_show, led_trigger_store);
  79 static struct attribute *led_trigger_attrs[] = {
  80         &dev_attr_trigger.attr,
  81         NULL,
  82 };
  83 static const struct attribute_group led_trigger_group = {
  84         .attrs = led_trigger_attrs,
  85 };
  86 #endif
  87
  88 static struct attribute *led_class_attrs[] = {
  89         &dev_attr_brightness.attr,
  90         &dev_attr_max_brightness.attr,
  91         NULL,
  92 };
  93
  94 static const struct attribute_group led_group = {
  95         .attrs = led_class_attrs,
  96 };
  97
  98 static const struct attribute_group *led_groups[] = {
  99         &led_group,
 100 #ifdef CONFIG_LEDS_TRIGGERS
 101         &led_trigger_group,
 102 #endif
 103         NULL,
 104 };
 105
 106 #ifdef CONFIG_LEDS_BRIGHTNESS_HW_CHANGED
 107 static ssize_t brightness_hw_changed_show(struct device *dev,
 108                 struct device_attribute *attr, char *buf)
 109 {
 110         struct led_classdev *led_cdev = dev_get_drvdata(dev);
 111
 112         if (led_cdev->brightness_hw_changed == -1)
 113                 return -ENODATA;
 114
 115         return sprintf(buf, "%u\n", led_cdev->brightness_hw_changed);
 116 }
 117
 118 static DEVICE_ATTR_RO(brightness_hw_changed);
 119
 120 static int led_add_brightness_hw_changed(struct led_classdev *led_cdev)
 121 {
 122         struct device *dev = led_cdev->dev;
 123         int ret;
 124
 125         ret = device_create_file(dev, &dev_attr_brightness_hw_changed);
 126         if (ret) {
 127                 dev_err(dev, "Error creating brightness_hw_changed\n");
 128                 return ret;
 129         }
 130
 131         led_cdev->brightness_hw_changed_kn =
 132                 sysfs_get_dirent(dev->kobj.sd, "brightness_hw_changed");
 133         if (!led_cdev->brightness_hw_changed_kn) {
 134                 dev_err(dev, "Error getting brightness_hw_changed kn\n");
 135                 device_remove_file(dev, &dev_attr_brightness_hw_changed);
 136                 return -ENXIO;
 137         }
 138
 139         return 0;
 140 }
 141
 142 static void led_remove_brightness_hw_changed(struct led_classdev *led_cdev)
 143 {
 144         sysfs_put(led_cdev->brightness_hw_changed_kn);
 145         device_remove_file(led_cdev->dev, &dev_attr_brightness_hw_changed);
 146 }
 147
 148 void led_classdev_notify_brightness_hw_changed(struct led_classdev *led_cdev,
 149                                                enum led_brightness brightness)
 150 {
 151         if (WARN_ON(!led_cdev->brightness_hw_changed_kn))
 152                 return;
 153
 154         led_cdev->brightness_hw_changed = brightness;
 155         sysfs_notify_dirent(led_cdev->brightness_hw_changed_kn);
 156 }
 157 EXPORT_SYMBOL_GPL(led_classdev_notify_brightness_hw_changed);
 158 #else
 159 static int led_add_brightness_hw_changed(struct led_classdev *led_cdev)
 160 {
 161         return 0;
 162 }
 163 static void led_remove_brightness_hw_changed(struct led_classdev *led_cdev)
 164 {
 165 }
 166 #endif
 167
 168 /**
 169  * led_classdev_suspend - suspend an led_classdev.
 170  * @led_cdev: the led_classdev to suspend.
 171  */
 172 void led_classdev_suspend(struct led_classdev *led_cdev)
 173 {
 174         led_cdev->flags |= LED_SUSPENDED;
 175         led_set_brightness_nopm(led_cdev, 0);
 176         flush_work(&led_cdev->set_brightness_work);
 177 }
 178 EXPORT_SYMBOL_GPL(led_classdev_suspend);
 179
 180 /**
 181  * led_classdev_resume - resume an led_classdev.
 182  * @led_cdev: the led_classdev to resume.
 183  */
 184 void led_classdev_resume(struct led_classdev *led_cdev)
 185 {
 186         led_set_brightness_nopm(led_cdev, led_cdev->brightness);
 187
 188         if (led_cdev->flash_resume)
 189                 led_cdev->flash_resume(led_cdev);
 190
 191         led_cdev->flags &= ~LED_SUSPENDED;
 192 }
 193 EXPORT_SYMBOL_GPL(led_classdev_resume);
 194
 195 #ifdef CONFIG_PM_SLEEP
 196 static int led_suspend(struct device *dev)
 197 {
 198         struct led_classdev *led_cdev = dev_get_drvdata(dev);
 199
 200         if (led_cdev->flags & LED_CORE_SUSPENDRESUME)
 201                 led_classdev_suspend(led_cdev);
 202
 203         return 0;
 204 }
 205
 206 static int led_resume(struct device *dev)
 207 {
 208         struct led_classdev *led_cdev = dev_get_drvdata(dev);
 209
 210         if (led_cdev->flags & LED_CORE_SUSPENDRESUME)
 211                 led_classdev_resume(led_cdev);
 212
 213         return 0;
 214 }
 215 #endif
 216
 217 static SIMPLE_DEV_PM_OPS(leds_class_dev_pm_ops, led_suspend, led_resume);
 218
 219 static int match_name(struct device *dev, const void *data)
 220 {
 221         if (!dev_name(dev))
 222                 return 0;
 223         return !strcmp(dev_name(dev), (char *)data);
 224 }
 225
 226 static int led_classdev_next_name(const char *init_name, char *name,
 227                                   size_t len)
 228 {
 229         unsigned int i = 0;
 230         int ret = 0;
 231         struct device *dev;
 232
 233         strlcpy(name, init_name, len);
 234
 235         while ((ret < len) &&
 236                (dev = class_find_device(leds_class, NULL, name, match_name))) {
 237                 put_device(dev);
 238                 ret = snprintf(name, len, "%s_%u", init_name, ++i);
 239         }
 240
 241         if (ret >= len)
 242                 return -ENOMEM;
 243
 244         return i;
 245 }
 246
 247 /**
 248  * of_led_classdev_register - register a new object of led_classdev class.
 249  *
 250  * @parent: parent of LED device
 251  * @led_cdev: the led_classdev structure for this device.
 252  * @np: DT node describing this LED
 253  */
 254 int of_led_classdev_register(struct device *parent, struct device_node *np,
 255                             struct led_classdev *led_cdev)
 256 {
 257         char name[LED_MAX_NAME_SIZE];
 258         int ret;
 259
 260         ret = led_classdev_next_name(led_cdev->name, name, sizeof(name));
 261         if (ret < 0)
 262                 return ret;
 263
 264         mutex_init(&led_cdev->led_access);
 265         mutex_lock(&led_cdev->led_access);
 266         led_cdev->dev = device_create_with_groups(leds_class, parent, 0,
 267                                 led_cdev, led_cdev->groups, "%s", name);
 268         if (IS_ERR(led_cdev->dev)) {
 269                 mutex_unlock(&led_cdev->led_access);
 270                 return PTR_ERR(led_cdev->dev);
 271         }
 272         led_cdev->dev->of_node = np;
 273
 274         if (ret)
 275                 dev_warn(parent, "Led %s renamed to %s due to name collision",
 276                                 led_cdev->name, dev_name(led_cdev->dev));
 277
 278         if (led_cdev->flags & LED_BRIGHT_HW_CHANGED) {
 279                 ret = led_add_brightness_hw_changed(led_cdev);
 280                 if (ret) {
 281                         device_unregister(led_cdev->dev);
 282                         mutex_unlock(&led_cdev->led_access);
 283                         return ret;
 284                 }
 285         }
 286
 287         led_cdev->work_flags = 0;
 288 #ifdef CONFIG_LEDS_TRIGGERS
 289         init_rwsem(&led_cdev->trigger_lock);
 290 #endif
 291 #ifdef CONFIG_LEDS_BRIGHTNESS_HW_CHANGED
 292         led_cdev->brightness_hw_changed = -1;
 293 #endif
 294         /* add to the list of leds */
 295         down_write(&leds_list_lock);
 296         list_add_tail(&led_cdev->node, &leds_list);
 297         up_write(&leds_list_lock);
 298
 299         if (!led_cdev->max_brightness)
 300                 led_cdev->max_brightness = LED_FULL;
 301
 302         led_update_brightness(led_cdev);
 303
 304         led_init_core(led_cdev);
 305
 306 #ifdef CONFIG_LEDS_TRIGGERS
 307         led_trigger_set_default(led_cdev);
 308 #endif
 309
 310         mutex_unlock(&led_cdev->led_access);
 311
 312         dev_dbg(parent, "Registered led device: %s\n",
 313                         led_cdev->name);
 314
 315         return 0;
 316 }
 317 EXPORT_SYMBOL_GPL(of_led_classdev_register);
 318
 319 /**
 320  * led_classdev_unregister - unregisters a object of led_properties class.
 321  * @led_cdev: the led device to unregister
 322  *
 323  * Unregisters a previously registered via led_classdev_register object.
 324  */
 325 void led_classdev_unregister(struct led_classdev *led_cdev)
 326 {
 327 #ifdef CONFIG_LEDS_TRIGGERS
 328         down_write(&led_cdev->trigger_lock);
 329         if (led_cdev->trigger)
 330                 led_trigger_set(led_cdev, NULL);
 331         up_write(&led_cdev->trigger_lock);
 332 #endif
 333
 334         led_cdev->flags |= LED_UNREGISTERING;
 335
 336         /* Stop blinking */
 337         led_stop_software_blink(led_cdev);
 338
 339         led_set_brightness(led_cdev, LED_OFF);
 340
 341         flush_work(&led_cdev->set_brightness_work);
 342
 343         if (led_cdev->flags & LED_BRIGHT_HW_CHANGED)
 344                 led_remove_brightness_hw_changed(led_cdev);
 345
 346         device_unregister(led_cdev->dev);
 347
 348         down_write(&leds_list_lock);
 349         list_del(&led_cdev->node);
 350         up_write(&leds_list_lock);
 351
 352         mutex_destroy(&led_cdev->led_access);
 353 }
 354 EXPORT_SYMBOL_GPL(led_classdev_unregister);
 355
 356 static void devm_led_classdev_release(struct device *dev, void *res)
 357 {
 358         led_classdev_unregister(*(struct led_classdev **)res);
 359 }
 360
 361 /**
 362  * devm_of_led_classdev_register - resource managed led_classdev_register()
 363  *
 364  * @parent: parent of LED device
 365  * @led_cdev: the led_classdev structure for this device.
 366  */
 367 int devm_of_led_classdev_register(struct device *parent,
 368                                   struct device_node *np,
 369                                   struct led_classdev *led_cdev)
 370 {
 371         struct led_classdev **dr;
 372         int rc;
 373
 374         dr = devres_alloc(devm_led_classdev_release, sizeof(*dr), GFP_KERNEL);
 375         if (!dr)
 376                 return -ENOMEM;
 377
 378         rc = of_led_classdev_register(parent, np, led_cdev);
 379         if (rc) {
 380                 devres_free(dr);
 381                 return rc;
 382         }
 383
 384         *dr = led_cdev;
 385         devres_add(parent, dr);
 386
 387         return 0;
 388 }
 389 EXPORT_SYMBOL_GPL(devm_of_led_classdev_register);
 390
 391 static int devm_led_classdev_match(struct device *dev, void *res, void *data)
 392 {
 393         struct led_cdev **p = res;
 394
 395         if (WARN_ON(!p || !*p))
 396                 return 0;
 397
 398         return *p == data;
 399 }
 400
 401 /**
 402  * devm_led_classdev_unregister() - resource managed led_classdev_unregister()
 403  * @parent: The device to unregister.
 404  * @led_cdev: the led_classdev structure for this device.
 405  */
 406 void devm_led_classdev_unregister(struct device *dev,
 407                                   struct led_classdev *led_cdev)
 408 {
 409         WARN_ON(devres_release(dev,
 410                                devm_led_classdev_release,
 411                                devm_led_classdev_match, led_cdev));
 412 }
 413 EXPORT_SYMBOL_GPL(devm_led_classdev_unregister);
 414
 415 static int __init leds_init(void)
 416 {
 417         leds_class = class_create(THIS_MODULE, "leds");
 418         if (IS_ERR(leds_class))
 419                 return PTR_ERR(leds_class);
 420         leds_class->pm = &leds_class_dev_pm_ops;
 421         leds_class->dev_groups = led_groups;
 422         return 0;
 423 }
 424
 425 static void __exit leds_exit(void)
 426 {
 427         class_destroy(leds_class);
 428 }
 429
 430 subsys_initcall(leds_init);
 431 module_exit(leds_exit);
 432
 433 MODULE_AUTHOR("John Lenz, Richard Purdie");
 434 MODULE_LICENSE("GPL");
 435 MODULE_DESCRIPTION("LED Class Interface");