drivers/leds/led-class.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * LED Class Core
   4  *
   5  * Copyright (C) 2005 John Lenz <lenz@cs.wisc.edu>
   6  * Copyright (C) 2005-2007 Richard Purdie <rpurdie@openedhand.com>
   7  */
   8
   9 #include <linux/ctype.h>
  10 #include <linux/device.h>
  11 #include <linux/err.h>
  12 #include <linux/init.h>
  13 #include <linux/kernel.h>
  14 #include <linux/leds.h>
  15 #include <linux/list.h>
  16 #include <linux/module.h>
  17 #include <linux/of.h>
  18 #include <linux/slab.h>
  19 #include <linux/spinlock.h>
  20 #include <linux/timer.h>
  21 #include <uapi/linux/uleds.h>
  22 #include "leds.h"
  23
  24 static struct class *leds_class;
  25
  26 static ssize_t brightness_show(struct device *dev,
  27                 struct device_attribute *attr, char *buf)
  28 {
  29         struct led_classdev *led_cdev = dev_get_drvdata(dev);
  30
  31         /* no lock needed for this */
  32         led_update_brightness(led_cdev);
  33
  34         return sprintf(buf, "%u\n", led_cdev->brightness);
  35 }
  36
  37 static ssize_t brightness_store(struct device *dev,
  38                 struct device_attribute *attr, const char *buf, size_t size)
  39 {
  40         struct led_classdev *led_cdev = dev_get_drvdata(dev);
  41         unsigned long state;
  42         ssize_t ret;
  43
  44         mutex_lock(&led_cdev->led_access);
  45
  46         if (led_sysfs_is_disabled(led_cdev)) {
  47                 ret = -EBUSY;
  48                 goto unlock;
  49         }
  50
  51         ret = kstrtoul(buf, 10, &state);
  52         if (ret)
  53                 goto unlock;
  54
  55         if (state == LED_OFF)
  56                 led_trigger_remove(led_cdev);
  57         led_set_brightness(led_cdev, state);
  58         flush_work(&led_cdev->set_brightness_work);
  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 #ifdef CONFIG_LEDS_BRIGHTNESS_HW_CHANGED
 106 static ssize_t brightness_hw_changed_show(struct device *dev,
 107                 struct device_attribute *attr, char *buf)
 108 {
 109         struct led_classdev *led_cdev = dev_get_drvdata(dev);
 110
 111         if (led_cdev->brightness_hw_changed == -1)
 112                 return -ENODATA;
 113
 114         return sprintf(buf, "%u\n", led_cdev->brightness_hw_changed);
 115 }
 116
 117 static DEVICE_ATTR_RO(brightness_hw_changed);
 118
 119 static int led_add_brightness_hw_changed(struct led_classdev *led_cdev)
 120 {
 121         struct device *dev = led_cdev->dev;
 122         int ret;
 123
 124         ret = device_create_file(dev, &dev_attr_brightness_hw_changed);
 125         if (ret) {
 126                 dev_err(dev, "Error creating brightness_hw_changed\n");
 127                 return ret;
 128         }
 129
 130         led_cdev->brightness_hw_changed_kn =
 131                 sysfs_get_dirent(dev->kobj.sd, "brightness_hw_changed");
 132         if (!led_cdev->brightness_hw_changed_kn) {
 133                 dev_err(dev, "Error getting brightness_hw_changed kn\n");
 134                 device_remove_file(dev, &dev_attr_brightness_hw_changed);
 135                 return -ENXIO;
 136         }
 137
 138         return 0;
 139 }
 140
 141 static void led_remove_brightness_hw_changed(struct led_classdev *led_cdev)
 142 {
 143         sysfs_put(led_cdev->brightness_hw_changed_kn);
 144         device_remove_file(led_cdev->dev, &dev_attr_brightness_hw_changed);
 145 }
 146
 147 void led_classdev_notify_brightness_hw_changed(struct led_classdev *led_cdev,
 148                                                enum led_brightness brightness)
 149 {
 150         if (WARN_ON(!led_cdev->brightness_hw_changed_kn))
 151                 return;
 152
 153         led_cdev->brightness_hw_changed = brightness;
 154         sysfs_notify_dirent(led_cdev->brightness_hw_changed_kn);
 155 }
 156 EXPORT_SYMBOL_GPL(led_classdev_notify_brightness_hw_changed);
 157 #else
 158 static int led_add_brightness_hw_changed(struct led_classdev *led_cdev)
 159 {
 160         return 0;
 161 }
 162 static void led_remove_brightness_hw_changed(struct led_classdev *led_cdev)
 163 {
 164 }
 165 #endif
 166
 167 /**
 168  * led_classdev_suspend - suspend an led_classdev.
 169  * @led_cdev: the led_classdev to suspend.
 170  */
 171 void led_classdev_suspend(struct led_classdev *led_cdev)
 172 {
 173         led_cdev->flags |= LED_SUSPENDED;
 174         led_set_brightness_nopm(led_cdev, 0);
 175 }
 176 EXPORT_SYMBOL_GPL(led_classdev_suspend);
 177
 178 /**
 179  * led_classdev_resume - resume an led_classdev.
 180  * @led_cdev: the led_classdev to resume.
 181  */
 182 void led_classdev_resume(struct led_classdev *led_cdev)
 183 {
 184         led_set_brightness_nopm(led_cdev, led_cdev->brightness);
 185
 186         if (led_cdev->flash_resume)
 187                 led_cdev->flash_resume(led_cdev);
 188
 189         led_cdev->flags &= ~LED_SUSPENDED;
 190 }
 191 EXPORT_SYMBOL_GPL(led_classdev_resume);
 192
 193 #ifdef CONFIG_PM_SLEEP
 194 static int led_suspend(struct device *dev)
 195 {
 196         struct led_classdev *led_cdev = dev_get_drvdata(dev);
 197
 198         if (led_cdev->flags & LED_CORE_SUSPENDRESUME)
 199                 led_classdev_suspend(led_cdev);
 200
 201         return 0;
 202 }
 203
 204 static int led_resume(struct device *dev)
 205 {
 206         struct led_classdev *led_cdev = dev_get_drvdata(dev);
 207
 208         if (led_cdev->flags & LED_CORE_SUSPENDRESUME)
 209                 led_classdev_resume(led_cdev);
 210
 211         return 0;
 212 }
 213 #endif
 214
 215 static SIMPLE_DEV_PM_OPS(leds_class_dev_pm_ops, led_suspend, led_resume);
 216
 217 static int match_name(struct device *dev, const void *data)
 218 {
 219         if (!dev_name(dev))
 220                 return 0;
 221         return !strcmp(dev_name(dev), (char *)data);
 222 }
 223
 224 static int led_classdev_next_name(const char *init_name, char *name,
 225                                   size_t len)
 226 {
 227         unsigned int i = 0;
 228         int ret = 0;
 229         struct device *dev;
 230
 231         strlcpy(name, init_name, len);
 232
 233         while ((ret < len) &&
 234                (dev = class_find_device(leds_class, NULL, name, match_name))) {
 235                 put_device(dev);
 236                 ret = snprintf(name, len, "%s_%u", init_name, ++i);
 237         }
 238
 239         if (ret >= len)
 240                 return -ENOMEM;
 241
 242         return i;
 243 }
 244
 245 /**
 246  * led_classdev_register_ext - register a new object of led_classdev class
 247  *                             with init data.
 248  *
 249  * @parent: parent of LED device
 250  * @led_cdev: the led_classdev structure for this device.
 251  * @init_data: LED class device initialization data
 252  */
 253 int led_classdev_register_ext(struct device *parent,
 254                               struct led_classdev *led_cdev,
 255                               struct led_init_data *init_data)
 256 {
 257         char composed_name[LED_MAX_NAME_SIZE];
 258         char final_name[LED_MAX_NAME_SIZE];
 259         const char *proposed_name = composed_name;
 260         int ret;
 261
 262         if (init_data) {
 263                 if (init_data->devname_mandatory && !init_data->devicename) {
 264                         dev_err(parent, "Mandatory device name is missing");
 265                         return -EINVAL;
 266                 }
 267                 ret = led_compose_name(parent, init_data, composed_name);
 268                 if (ret < 0)
 269                         return ret;
 270         } else {
 271                 proposed_name = led_cdev->name;
 272         }
 273
 274         ret = led_classdev_next_name(proposed_name, final_name, sizeof(final_name));
 275         if (ret < 0)
 276                 return ret;
 277
 278         mutex_init(&led_cdev->led_access);
 279         mutex_lock(&led_cdev->led_access);
 280         led_cdev->dev = device_create_with_groups(leds_class, parent, 0,
 281                                 led_cdev, led_cdev->groups, "%s", final_name);
 282         if (IS_ERR(led_cdev->dev)) {
 283                 mutex_unlock(&led_cdev->led_access);
 284                 return PTR_ERR(led_cdev->dev);
 285         }
 286         if (init_data && init_data->fwnode)
 287                 led_cdev->dev->of_node = to_of_node(init_data->fwnode);
 288
 289         if (ret)
 290                 dev_warn(parent, "Led %s renamed to %s due to name collision",
 291                                 led_cdev->name, dev_name(led_cdev->dev));
 292
 293         if (led_cdev->flags & LED_BRIGHT_HW_CHANGED) {
 294                 ret = led_add_brightness_hw_changed(led_cdev);
 295                 if (ret) {
 296                         device_unregister(led_cdev->dev);
 297                         mutex_unlock(&led_cdev->led_access);
 298                         return ret;
 299                 }
 300         }
 301
 302         led_cdev->work_flags = 0;
 303 #ifdef CONFIG_LEDS_TRIGGERS
 304         init_rwsem(&led_cdev->trigger_lock);
 305 #endif
 306 #ifdef CONFIG_LEDS_BRIGHTNESS_HW_CHANGED
 307         led_cdev->brightness_hw_changed = -1;
 308 #endif
 309         /* add to the list of leds */
 310         down_write(&leds_list_lock);
 311         list_add_tail(&led_cdev->node, &leds_list);
 312         up_write(&leds_list_lock);
 313
 314         if (!led_cdev->max_brightness)
 315                 led_cdev->max_brightness = LED_FULL;
 316
 317         led_update_brightness(led_cdev);
 318
 319         led_init_core(led_cdev);
 320
 321 #ifdef CONFIG_LEDS_TRIGGERS
 322         led_trigger_set_default(led_cdev);
 323 #endif
 324
 325         mutex_unlock(&led_cdev->led_access);
 326
 327         dev_dbg(parent, "Registered led device: %s\n",
 328                         led_cdev->name);
 329
 330         return 0;
 331 }
 332 EXPORT_SYMBOL_GPL(led_classdev_register_ext);
 333
 334 /**
 335  * led_classdev_unregister - unregisters a object of led_properties class.
 336  * @led_cdev: the led device to unregister
 337  *
 338  * Unregisters a previously registered via led_classdev_register object.
 339  */
 340 void led_classdev_unregister(struct led_classdev *led_cdev)
 341 {
 342 #ifdef CONFIG_LEDS_TRIGGERS
 343         down_write(&led_cdev->trigger_lock);
 344         if (led_cdev->trigger)
 345                 led_trigger_set(led_cdev, NULL);
 346         up_write(&led_cdev->trigger_lock);
 347 #endif
 348
 349         led_cdev->flags |= LED_UNREGISTERING;
 350
 351         /* Stop blinking */
 352         led_stop_software_blink(led_cdev);
 353
 354         led_set_brightness(led_cdev, LED_OFF);
 355
 356         flush_work(&led_cdev->set_brightness_work);
 357
 358         if (led_cdev->flags & LED_BRIGHT_HW_CHANGED)
 359                 led_remove_brightness_hw_changed(led_cdev);
 360
 361         device_unregister(led_cdev->dev);
 362
 363         down_write(&leds_list_lock);
 364         list_del(&led_cdev->node);
 365         up_write(&leds_list_lock);
 366
 367         mutex_destroy(&led_cdev->led_access);
 368 }
 369 EXPORT_SYMBOL_GPL(led_classdev_unregister);
 370
 371 static void devm_led_classdev_release(struct device *dev, void *res)
 372 {
 373         led_classdev_unregister(*(struct led_classdev **)res);
 374 }
 375
 376 /**
 377  * devm_led_classdev_register_ext - resource managed led_classdev_register_ext()
 378  *
 379  * @parent: parent of LED device
 380  * @led_cdev: the led_classdev structure for this device.
 381  * @init_data: LED class device initialization data
 382  */
 383 int devm_led_classdev_register_ext(struct device *parent,
 384                                    struct led_classdev *led_cdev,
 385                                    struct led_init_data *init_data)
 386 {
 387         struct led_classdev **dr;
 388         int rc;
 389
 390         dr = devres_alloc(devm_led_classdev_release, sizeof(*dr), GFP_KERNEL);
 391         if (!dr)
 392                 return -ENOMEM;
 393
 394         rc = led_classdev_register_ext(parent, led_cdev, init_data);
 395         if (rc) {
 396                 devres_free(dr);
 397                 return rc;
 398         }
 399
 400         *dr = led_cdev;
 401         devres_add(parent, dr);
 402
 403         return 0;
 404 }
 405 EXPORT_SYMBOL_GPL(devm_led_classdev_register_ext);
 406
 407 static int devm_led_classdev_match(struct device *dev, void *res, void *data)
 408 {
 409         struct led_cdev **p = res;
 410
 411         if (WARN_ON(!p || !*p))
 412                 return 0;
 413
 414         return *p == data;
 415 }
 416
 417 /**
 418  * devm_led_classdev_unregister() - resource managed led_classdev_unregister()
 419  * @parent: The device to unregister.
 420  * @led_cdev: the led_classdev structure for this device.
 421  */
 422 void devm_led_classdev_unregister(struct device *dev,
 423                                   struct led_classdev *led_cdev)
 424 {
 425         WARN_ON(devres_release(dev,
 426                                devm_led_classdev_release,
 427                                devm_led_classdev_match, led_cdev));
 428 }
 429 EXPORT_SYMBOL_GPL(devm_led_classdev_unregister);
 430
 431 static int __init leds_init(void)
 432 {
 433         leds_class = class_create(THIS_MODULE, "leds");
 434         if (IS_ERR(leds_class))
 435                 return PTR_ERR(leds_class);
 436         leds_class->pm = &leds_class_dev_pm_ops;
 437         leds_class->dev_groups = led_groups;
 438         return 0;
 439 }
 440
 441 static void __exit leds_exit(void)
 442 {
 443         class_destroy(leds_class);
 444 }
 445
 446 subsys_initcall(leds_init);
 447 module_exit(leds_exit);
 448
 449 MODULE_AUTHOR("John Lenz, Richard Purdie");
 450 MODULE_LICENSE("GPL");
 451 MODULE_DESCRIPTION("LED Class Interface");