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 flush_work(&led_cdev->set_brightness_work); 61 62 ret = size; 63 unlock: 64 mutex_unlock(&led_cdev->led_access); 65 return ret; 66 } 67 static DEVICE_ATTR_RW(brightness); 68 69 static ssize_t max_brightness_show(struct device *dev, 70 struct device_attribute *attr, char *buf) 71 { 72 struct led_classdev *led_cdev = dev_get_drvdata(dev); 73 74 return sprintf(buf, "%u\n", led_cdev->max_brightness); 75 } 76 static DEVICE_ATTR_RO(max_brightness); 77 78 #ifdef CONFIG_LEDS_TRIGGERS 79 static DEVICE_ATTR(trigger, 0644, led_trigger_show, led_trigger_store); 80 static struct attribute *led_trigger_attrs[] = { 81 &dev_attr_trigger.attr, 82 NULL, 83 }; 84 static const struct attribute_group led_trigger_group = { 85 .attrs = led_trigger_attrs, 86 }; 87 #endif 88 89 static struct attribute *led_class_attrs[] = { 90 &dev_attr_brightness.attr, 91 &dev_attr_max_brightness.attr, 92 NULL, 93 }; 94 95 static const struct attribute_group led_group = { 96 .attrs = led_class_attrs, 97 }; 98 99 static const struct attribute_group *led_groups[] = { 100 &led_group, 101 #ifdef CONFIG_LEDS_TRIGGERS 102 &led_trigger_group, 103 #endif 104 NULL, 105 }; 106 107 #ifdef CONFIG_LEDS_BRIGHTNESS_HW_CHANGED 108 static ssize_t brightness_hw_changed_show(struct device *dev, 109 struct device_attribute *attr, char *buf) 110 { 111 struct led_classdev *led_cdev = dev_get_drvdata(dev); 112 113 if (led_cdev->brightness_hw_changed == -1) 114 return -ENODATA; 115 116 return sprintf(buf, "%u\n", led_cdev->brightness_hw_changed); 117 } 118 119 static DEVICE_ATTR_RO(brightness_hw_changed); 120 121 static int led_add_brightness_hw_changed(struct led_classdev *led_cdev) 122 { 123 struct device *dev = led_cdev->dev; 124 int ret; 125 126 ret = device_create_file(dev, &dev_attr_brightness_hw_changed); 127 if (ret) { 128 dev_err(dev, "Error creating brightness_hw_changed\n"); 129 return ret; 130 } 131 132 led_cdev->brightness_hw_changed_kn = 133 sysfs_get_dirent(dev->kobj.sd, "brightness_hw_changed"); 134 if (!led_cdev->brightness_hw_changed_kn) { 135 dev_err(dev, "Error getting brightness_hw_changed kn\n"); 136 device_remove_file(dev, &dev_attr_brightness_hw_changed); 137 return -ENXIO; 138 } 139 140 return 0; 141 } 142 143 static void led_remove_brightness_hw_changed(struct led_classdev *led_cdev) 144 { 145 sysfs_put(led_cdev->brightness_hw_changed_kn); 146 device_remove_file(led_cdev->dev, &dev_attr_brightness_hw_changed); 147 } 148 149 void led_classdev_notify_brightness_hw_changed(struct led_classdev *led_cdev, 150 enum led_brightness brightness) 151 { 152 if (WARN_ON(!led_cdev->brightness_hw_changed_kn)) 153 return; 154 155 led_cdev->brightness_hw_changed = brightness; 156 sysfs_notify_dirent(led_cdev->brightness_hw_changed_kn); 157 } 158 EXPORT_SYMBOL_GPL(led_classdev_notify_brightness_hw_changed); 159 #else 160 static int led_add_brightness_hw_changed(struct led_classdev *led_cdev) 161 { 162 return 0; 163 } 164 static void led_remove_brightness_hw_changed(struct led_classdev *led_cdev) 165 { 166 } 167 #endif 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_set_brightness_nopm(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_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"); 436