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"); 408