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 /**
 107  * led_classdev_suspend - suspend an led_classdev.
 108  * @led_cdev: the led_classdev to suspend.
 109  */
 110 void led_classdev_suspend(struct led_classdev *led_cdev)
 111 {
 112         led_cdev->flags |= LED_SUSPENDED;
 113         led_set_brightness_nopm(led_cdev, 0);
 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[LED_MAX_NAME_SIZE];
 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         led_cdev->work_flags = 0;
 208 #ifdef CONFIG_LEDS_TRIGGERS
 209         init_rwsem(&led_cdev->trigger_lock);
 210 #endif
 211         mutex_init(&led_cdev->led_access);
 212         /* add to the list of leds */
 213         down_write(&leds_list_lock);
 214         list_add_tail(&led_cdev->node, &leds_list);
 215         up_write(&leds_list_lock);
 216
 217         if (!led_cdev->max_brightness)
 218                 led_cdev->max_brightness = LED_FULL;
 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         led_cdev->flags |= LED_UNREGISTERING;
 251
 252         /* Stop blinking */
 253         led_stop_software_blink(led_cdev);
 254
 255         led_set_brightness(led_cdev, LED_OFF);
 256
 257         flush_work(&led_cdev->set_brightness_work);
 258
 259         device_unregister(led_cdev->dev);
 260
 261         down_write(&leds_list_lock);
 262         list_del(&led_cdev->node);
 263         up_write(&leds_list_lock);
 264
 265         mutex_destroy(&led_cdev->led_access);
 266 }
 267 EXPORT_SYMBOL_GPL(led_classdev_unregister);
 268
 269 static void devm_led_classdev_release(struct device *dev, void *res)
 270 {
 271         led_classdev_unregister(*(struct led_classdev **)res);
 272 }
 273
 274 /**
 275  * devm_led_classdev_register - resource managed led_classdev_register()
 276  * @parent: The device to register.
 277  * @led_cdev: the led_classdev structure for this device.
 278  */
 279 int devm_led_classdev_register(struct device *parent,
 280                                struct led_classdev *led_cdev)
 281 {
 282         struct led_classdev **dr;
 283         int rc;
 284
 285         dr = devres_alloc(devm_led_classdev_release, sizeof(*dr), GFP_KERNEL);
 286         if (!dr)
 287                 return -ENOMEM;
 288
 289         rc = led_classdev_register(parent, led_cdev);
 290         if (rc) {
 291                 devres_free(dr);
 292                 return rc;
 293         }
 294
 295         *dr = led_cdev;
 296         devres_add(parent, dr);
 297
 298         return 0;
 299 }
 300 EXPORT_SYMBOL_GPL(devm_led_classdev_register);
 301
 302 static int devm_led_classdev_match(struct device *dev, void *res, void *data)
 303 {
 304         struct led_cdev **p = res;
 305
 306         if (WARN_ON(!p || !*p))
 307                 return 0;
 308
 309         return *p == data;
 310 }
 311
 312 /**
 313  * devm_led_classdev_unregister() - resource managed led_classdev_unregister()
 314  * @parent: The device to unregister.
 315  * @led_cdev: the led_classdev structure for this device.
 316  */
 317 void devm_led_classdev_unregister(struct device *dev,
 318                                   struct led_classdev *led_cdev)
 319 {
 320         WARN_ON(devres_release(dev,
 321                                devm_led_classdev_release,
 322                                devm_led_classdev_match, led_cdev));
 323 }
 324 EXPORT_SYMBOL_GPL(devm_led_classdev_unregister);
 325
 326 static int __init leds_init(void)
 327 {
 328         leds_class = class_create(THIS_MODULE, "leds");
 329         if (IS_ERR(leds_class))
 330                 return PTR_ERR(leds_class);
 331         leds_class->pm = &leds_class_dev_pm_ops;
 332         leds_class->dev_groups = led_groups;
 333         return 0;
 334 }
 335
 336 static void __exit leds_exit(void)
 337 {
 338         class_destroy(leds_class);
 339 }
 340
 341 subsys_initcall(leds_init);
 342 module_exit(leds_exit);
 343
 344 MODULE_AUTHOR("John Lenz, Richard Purdie");
 345 MODULE_LICENSE("GPL");
 346 MODULE_DESCRIPTION("LED Class Interface");