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 static void led_timer_function(unsigned long data)
 106 {
 107         struct led_classdev *led_cdev = (void *)data;
 108         unsigned long brightness;
 109         unsigned long delay;
 110
 111         if (!led_cdev->blink_delay_on || !led_cdev->blink_delay_off) {
 112                 led_set_brightness_async(led_cdev, LED_OFF);
 113                 return;
 114         }
 115
 116         if (led_cdev->flags & LED_BLINK_ONESHOT_STOP) {
 117                 led_cdev->flags &= ~LED_BLINK_ONESHOT_STOP;
 118                 return;
 119         }
 120
 121         brightness = led_get_brightness(led_cdev);
 122         if (!brightness) {
 123                 /* Time to switch the LED on. */
 124                 if (led_cdev->delayed_set_value) {
 125                         led_cdev->blink_brightness =
 126                                         led_cdev->delayed_set_value;
 127                         led_cdev->delayed_set_value = 0;
 128                 }
 129                 brightness = led_cdev->blink_brightness;
 130                 delay = led_cdev->blink_delay_on;
 131         } else {
 132                 /* Store the current brightness value to be able
 133                  * to restore it when the delay_off period is over.
 134                  */
 135                 led_cdev->blink_brightness = brightness;
 136                 brightness = LED_OFF;
 137                 delay = led_cdev->blink_delay_off;
 138         }
 139
 140         led_set_brightness_async(led_cdev, brightness);
 141
 142         /* Return in next iteration if led is in one-shot mode and we are in
 143          * the final blink state so that the led is toggled each delay_on +
 144          * delay_off milliseconds in worst case.
 145          */
 146         if (led_cdev->flags & LED_BLINK_ONESHOT) {
 147                 if (led_cdev->flags & LED_BLINK_INVERT) {
 148                         if (brightness)
 149                                 led_cdev->flags |= LED_BLINK_ONESHOT_STOP;
 150                 } else {
 151                         if (!brightness)
 152                                 led_cdev->flags |= LED_BLINK_ONESHOT_STOP;
 153                 }
 154         }
 155
 156         mod_timer(&led_cdev->blink_timer, jiffies + msecs_to_jiffies(delay));
 157 }
 158
 159 static void set_brightness_delayed(struct work_struct *ws)
 160 {
 161         struct led_classdev *led_cdev =
 162                 container_of(ws, struct led_classdev, set_brightness_work);
 163
 164         led_stop_software_blink(led_cdev);
 165
 166         led_set_brightness_async(led_cdev, led_cdev->delayed_set_value);
 167 }
 168
 169 /**
 170  * led_classdev_suspend - suspend an led_classdev.
 171  * @led_cdev: the led_classdev to suspend.
 172  */
 173 void led_classdev_suspend(struct led_classdev *led_cdev)
 174 {
 175         led_cdev->flags |= LED_SUSPENDED;
 176         led_cdev->brightness_set(led_cdev, 0);
 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_cdev->brightness_set(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
 232         strlcpy(name, init_name, len);
 233
 234         while (class_find_device(leds_class, NULL, name, match_name) &&
 235                (ret < len))
 236                 ret = snprintf(name, len, "%s_%u", init_name, ++i);
 237
 238         if (ret >= len)
 239                 return -ENOMEM;
 240
 241         return i;
 242 }
 243
 244 /**
 245  * led_classdev_register - register a new object of led_classdev class.
 246  * @parent: The device to register.
 247  * @led_cdev: the led_classdev structure for this device.
 248  */
 249 int led_classdev_register(struct device *parent, struct led_classdev *led_cdev)
 250 {
 251         char name[64];
 252         int ret;
 253
 254         ret = led_classdev_next_name(led_cdev->name, name, sizeof(name));
 255         if (ret < 0)
 256                 return ret;
 257
 258         led_cdev->dev = device_create_with_groups(leds_class, parent, 0,
 259                                 led_cdev, led_cdev->groups, "%s", name);
 260         if (IS_ERR(led_cdev->dev))
 261                 return PTR_ERR(led_cdev->dev);
 262
 263         if (ret)
 264                 dev_warn(parent, "Led %s renamed to %s due to name collision",
 265                                 led_cdev->name, dev_name(led_cdev->dev));
 266
 267 #ifdef CONFIG_LEDS_TRIGGERS
 268         init_rwsem(&led_cdev->trigger_lock);
 269 #endif
 270         mutex_init(&led_cdev->led_access);
 271         /* add to the list of leds */
 272         down_write(&leds_list_lock);
 273         list_add_tail(&led_cdev->node, &leds_list);
 274         up_write(&leds_list_lock);
 275
 276         if (!led_cdev->max_brightness)
 277                 led_cdev->max_brightness = LED_FULL;
 278
 279         led_cdev->flags |= SET_BRIGHTNESS_ASYNC;
 280
 281         led_update_brightness(led_cdev);
 282
 283         INIT_WORK(&led_cdev->set_brightness_work, set_brightness_delayed);
 284
 285         setup_timer(&led_cdev->blink_timer, led_timer_function,
 286                     (unsigned long)led_cdev);
 287
 288 #ifdef CONFIG_LEDS_TRIGGERS
 289         led_trigger_set_default(led_cdev);
 290 #endif
 291
 292         dev_dbg(parent, "Registered led device: %s\n",
 293                         led_cdev->name);
 294
 295         return 0;
 296 }
 297 EXPORT_SYMBOL_GPL(led_classdev_register);
 298
 299 /**
 300  * led_classdev_unregister - unregisters a object of led_properties class.
 301  * @led_cdev: the led device to unregister
 302  *
 303  * Unregisters a previously registered via led_classdev_register object.
 304  */
 305 void led_classdev_unregister(struct led_classdev *led_cdev)
 306 {
 307 #ifdef CONFIG_LEDS_TRIGGERS
 308         down_write(&led_cdev->trigger_lock);
 309         if (led_cdev->trigger)
 310                 led_trigger_set(led_cdev, NULL);
 311         up_write(&led_cdev->trigger_lock);
 312 #endif
 313
 314         cancel_work_sync(&led_cdev->set_brightness_work);
 315
 316         /* Stop blinking */
 317         led_stop_software_blink(led_cdev);
 318         led_set_brightness(led_cdev, LED_OFF);
 319
 320         device_unregister(led_cdev->dev);
 321
 322         down_write(&leds_list_lock);
 323         list_del(&led_cdev->node);
 324         up_write(&leds_list_lock);
 325
 326         mutex_destroy(&led_cdev->led_access);
 327 }
 328 EXPORT_SYMBOL_GPL(led_classdev_unregister);
 329
 330 static void devm_led_classdev_release(struct device *dev, void *res)
 331 {
 332         led_classdev_unregister(*(struct led_classdev **)res);
 333 }
 334
 335 /**
 336  * devm_led_classdev_register - resource managed led_classdev_register()
 337  * @parent: The device to register.
 338  * @led_cdev: the led_classdev structure for this device.
 339  */
 340 int devm_led_classdev_register(struct device *parent,
 341                                struct led_classdev *led_cdev)
 342 {
 343         struct led_classdev **dr;
 344         int rc;
 345
 346         dr = devres_alloc(devm_led_classdev_release, sizeof(*dr), GFP_KERNEL);
 347         if (!dr)
 348                 return -ENOMEM;
 349
 350         rc = led_classdev_register(parent, led_cdev);
 351         if (rc) {
 352                 devres_free(dr);
 353                 return rc;
 354         }
 355
 356         *dr = led_cdev;
 357         devres_add(parent, dr);
 358
 359         return 0;
 360 }
 361 EXPORT_SYMBOL_GPL(devm_led_classdev_register);
 362
 363 static int devm_led_classdev_match(struct device *dev, void *res, void *data)
 364 {
 365         struct led_cdev **p = res;
 366
 367         if (WARN_ON(!p || !*p))
 368                 return 0;
 369
 370         return *p == data;
 371 }
 372
 373 /**
 374  * devm_led_classdev_unregister() - resource managed led_classdev_unregister()
 375  * @parent: The device to unregister.
 376  * @led_cdev: the led_classdev structure for this device.
 377  */
 378 void devm_led_classdev_unregister(struct device *dev,
 379                                   struct led_classdev *led_cdev)
 380 {
 381         WARN_ON(devres_release(dev,
 382                                devm_led_classdev_release,
 383                                devm_led_classdev_match, led_cdev));
 384 }
 385 EXPORT_SYMBOL_GPL(devm_led_classdev_unregister);
 386
 387 static int __init leds_init(void)
 388 {
 389         leds_class = class_create(THIS_MODULE, "leds");
 390         if (IS_ERR(leds_class))
 391                 return PTR_ERR(leds_class);
 392         leds_class->pm = &leds_class_dev_pm_ops;
 393         leds_class->dev_groups = led_groups;
 394         return 0;
 395 }
 396
 397 static void __exit leds_exit(void)
 398 {
 399         class_destroy(leds_class);
 400 }
 401
 402 subsys_initcall(leds_init);
 403 module_exit(leds_exit);
 404
 405 MODULE_AUTHOR("John Lenz, Richard Purdie");
 406 MODULE_LICENSE("GPL");
 407 MODULE_DESCRIPTION("LED Class Interface");