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 } 177 EXPORT_SYMBOL_GPL(led_classdev_suspend); 178 179 /** 180 * led_classdev_resume - resume an led_classdev. 181 * @led_cdev: the led_classdev to resume. 182 */ 183 void led_classdev_resume(struct led_classdev *led_cdev) 184 { 185 led_set_brightness_nopm(led_cdev, led_cdev->brightness); 186 187 if (led_cdev->flash_resume) 188 led_cdev->flash_resume(led_cdev); 189 190 led_cdev->flags &= ~LED_SUSPENDED; 191 } 192 EXPORT_SYMBOL_GPL(led_classdev_resume); 193 194 #ifdef CONFIG_PM_SLEEP 195 static int led_suspend(struct device *dev) 196 { 197 struct led_classdev *led_cdev = dev_get_drvdata(dev); 198 199 if (led_cdev->flags & LED_CORE_SUSPENDRESUME) 200 led_classdev_suspend(led_cdev); 201 202 return 0; 203 } 204 205 static int led_resume(struct device *dev) 206 { 207 struct led_classdev *led_cdev = dev_get_drvdata(dev); 208 209 if (led_cdev->flags & LED_CORE_SUSPENDRESUME) 210 led_classdev_resume(led_cdev); 211 212 return 0; 213 } 214 #endif 215 216 static SIMPLE_DEV_PM_OPS(leds_class_dev_pm_ops, led_suspend, led_resume); 217 218 static int match_name(struct device *dev, const void *data) 219 { 220 if (!dev_name(dev)) 221 return 0; 222 return !strcmp(dev_name(dev), (char *)data); 223 } 224 225 static int led_classdev_next_name(const char *init_name, char *name, 226 size_t len) 227 { 228 unsigned int i = 0; 229 int ret = 0; 230 struct device *dev; 231 232 strlcpy(name, init_name, len); 233 234 while ((ret < len) && 235 (dev = class_find_device(leds_class, NULL, name, match_name))) { 236 put_device(dev); 237 ret = snprintf(name, len, "%s_%u", init_name, ++i); 238 } 239 240 if (ret >= len) 241 return -ENOMEM; 242 243 return i; 244 } 245 246 /** 247 * of_led_classdev_register - register a new object of led_classdev class. 248 * 249 * @parent: parent of LED device 250 * @led_cdev: the led_classdev structure for this device. 251 * @np: DT node describing this LED 252 */ 253 int of_led_classdev_register(struct device *parent, struct device_node *np, 254 struct led_classdev *led_cdev) 255 { 256 char name[LED_MAX_NAME_SIZE]; 257 int ret; 258 259 ret = led_classdev_next_name(led_cdev->name, name, sizeof(name)); 260 if (ret < 0) 261 return ret; 262 263 led_cdev->dev = device_create_with_groups(leds_class, parent, 0, 264 led_cdev, led_cdev->groups, "%s", name); 265 if (IS_ERR(led_cdev->dev)) 266 return PTR_ERR(led_cdev->dev); 267 led_cdev->dev->of_node = np; 268 269 if (ret) 270 dev_warn(parent, "Led %s renamed to %s due to name collision", 271 led_cdev->name, dev_name(led_cdev->dev)); 272 273 if (led_cdev->flags & LED_BRIGHT_HW_CHANGED) { 274 ret = led_add_brightness_hw_changed(led_cdev); 275 if (ret) { 276 device_unregister(led_cdev->dev); 277 return ret; 278 } 279 } 280 281 led_cdev->work_flags = 0; 282 #ifdef CONFIG_LEDS_TRIGGERS 283 init_rwsem(&led_cdev->trigger_lock); 284 #endif 285 #ifdef CONFIG_LEDS_BRIGHTNESS_HW_CHANGED 286 led_cdev->brightness_hw_changed = -1; 287 #endif 288 mutex_init(&led_cdev->led_access); 289 /* add to the list of leds */ 290 down_write(&leds_list_lock); 291 list_add_tail(&led_cdev->node, &leds_list); 292 up_write(&leds_list_lock); 293 294 if (!led_cdev->max_brightness) 295 led_cdev->max_brightness = LED_FULL; 296 297 led_update_brightness(led_cdev); 298 299 led_init_core(led_cdev); 300 301 #ifdef CONFIG_LEDS_TRIGGERS 302 led_trigger_set_default(led_cdev); 303 #endif 304 305 dev_dbg(parent, "Registered led device: %s\n", 306 led_cdev->name); 307 308 return 0; 309 } 310 EXPORT_SYMBOL_GPL(of_led_classdev_register); 311 312 /** 313 * led_classdev_unregister - unregisters a object of led_properties class. 314 * @led_cdev: the led device to unregister 315 * 316 * Unregisters a previously registered via led_classdev_register object. 317 */ 318 void led_classdev_unregister(struct led_classdev *led_cdev) 319 { 320 #ifdef CONFIG_LEDS_TRIGGERS 321 down_write(&led_cdev->trigger_lock); 322 if (led_cdev->trigger) 323 led_trigger_set(led_cdev, NULL); 324 up_write(&led_cdev->trigger_lock); 325 #endif 326 327 led_cdev->flags |= LED_UNREGISTERING; 328 329 /* Stop blinking */ 330 led_stop_software_blink(led_cdev); 331 332 led_set_brightness(led_cdev, LED_OFF); 333 334 flush_work(&led_cdev->set_brightness_work); 335 336 if (led_cdev->flags & LED_BRIGHT_HW_CHANGED) 337 led_remove_brightness_hw_changed(led_cdev); 338 339 device_unregister(led_cdev->dev); 340 341 down_write(&leds_list_lock); 342 list_del(&led_cdev->node); 343 up_write(&leds_list_lock); 344 345 mutex_destroy(&led_cdev->led_access); 346 } 347 EXPORT_SYMBOL_GPL(led_classdev_unregister); 348 349 static void devm_led_classdev_release(struct device *dev, void *res) 350 { 351 led_classdev_unregister(*(struct led_classdev **)res); 352 } 353 354 /** 355 * devm_of_led_classdev_register - resource managed led_classdev_register() 356 * 357 * @parent: parent of LED device 358 * @led_cdev: the led_classdev structure for this device. 359 */ 360 int devm_of_led_classdev_register(struct device *parent, 361 struct device_node *np, 362 struct led_classdev *led_cdev) 363 { 364 struct led_classdev **dr; 365 int rc; 366 367 dr = devres_alloc(devm_led_classdev_release, sizeof(*dr), GFP_KERNEL); 368 if (!dr) 369 return -ENOMEM; 370 371 rc = of_led_classdev_register(parent, np, led_cdev); 372 if (rc) { 373 devres_free(dr); 374 return rc; 375 } 376 377 *dr = led_cdev; 378 devres_add(parent, dr); 379 380 return 0; 381 } 382 EXPORT_SYMBOL_GPL(devm_of_led_classdev_register); 383 384 static int devm_led_classdev_match(struct device *dev, void *res, void *data) 385 { 386 struct led_cdev **p = res; 387 388 if (WARN_ON(!p || !*p)) 389 return 0; 390 391 return *p == data; 392 } 393 394 /** 395 * devm_led_classdev_unregister() - resource managed led_classdev_unregister() 396 * @parent: The device to unregister. 397 * @led_cdev: the led_classdev structure for this device. 398 */ 399 void devm_led_classdev_unregister(struct device *dev, 400 struct led_classdev *led_cdev) 401 { 402 WARN_ON(devres_release(dev, 403 devm_led_classdev_release, 404 devm_led_classdev_match, led_cdev)); 405 } 406 EXPORT_SYMBOL_GPL(devm_led_classdev_unregister); 407 408 static int __init leds_init(void) 409 { 410 leds_class = class_create(THIS_MODULE, "leds"); 411 if (IS_ERR(leds_class)) 412 return PTR_ERR(leds_class); 413 leds_class->pm = &leds_class_dev_pm_ops; 414 leds_class->dev_groups = led_groups; 415 return 0; 416 } 417 418 static void __exit leds_exit(void) 419 { 420 class_destroy(leds_class); 421 } 422 423 subsys_initcall(leds_init); 424 module_exit(leds_exit); 425 426 MODULE_AUTHOR("John Lenz, Richard Purdie"); 427 MODULE_LICENSE("GPL"); 428 MODULE_DESCRIPTION("LED Class Interface"); 429