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"); 347