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 /** 106 * led_classdev_suspend - suspend an led_classdev. 107 * @led_cdev: the led_classdev to suspend. 108 */ 109 void led_classdev_suspend(struct led_classdev *led_cdev) 110 { 111 led_cdev->flags |= LED_SUSPENDED; 112 led_set_brightness_nopm(led_cdev, 0); 113 } 114 EXPORT_SYMBOL_GPL(led_classdev_suspend); 115 116 /** 117 * led_classdev_resume - resume an led_classdev. 118 * @led_cdev: the led_classdev to resume. 119 */ 120 void led_classdev_resume(struct led_classdev *led_cdev) 121 { 122 led_set_brightness_nopm(led_cdev, led_cdev->brightness); 123 124 if (led_cdev->flash_resume) 125 led_cdev->flash_resume(led_cdev); 126 127 led_cdev->flags &= ~LED_SUSPENDED; 128 } 129 EXPORT_SYMBOL_GPL(led_classdev_resume); 130 131 #ifdef CONFIG_PM_SLEEP 132 static int led_suspend(struct device *dev) 133 { 134 struct led_classdev *led_cdev = dev_get_drvdata(dev); 135 136 if (led_cdev->flags & LED_CORE_SUSPENDRESUME) 137 led_classdev_suspend(led_cdev); 138 139 return 0; 140 } 141 142 static int led_resume(struct device *dev) 143 { 144 struct led_classdev *led_cdev = dev_get_drvdata(dev); 145 146 if (led_cdev->flags & LED_CORE_SUSPENDRESUME) 147 led_classdev_resume(led_cdev); 148 149 return 0; 150 } 151 #endif 152 153 static SIMPLE_DEV_PM_OPS(leds_class_dev_pm_ops, led_suspend, led_resume); 154 155 static int match_name(struct device *dev, const void *data) 156 { 157 if (!dev_name(dev)) 158 return 0; 159 return !strcmp(dev_name(dev), (char *)data); 160 } 161 162 static int led_classdev_next_name(const char *init_name, char *name, 163 size_t len) 164 { 165 unsigned int i = 0; 166 int ret = 0; 167 struct device *dev; 168 169 strlcpy(name, init_name, len); 170 171 while ((ret < len) && 172 (dev = class_find_device(leds_class, NULL, name, match_name))) { 173 put_device(dev); 174 ret = snprintf(name, len, "%s_%u", init_name, ++i); 175 } 176 177 if (ret >= len) 178 return -ENOMEM; 179 180 return i; 181 } 182 183 /** 184 * led_classdev_register - register a new object of led_classdev class. 185 * @parent: The device to register. 186 * @led_cdev: the led_classdev structure for this device. 187 */ 188 int led_classdev_register(struct device *parent, struct led_classdev *led_cdev) 189 { 190 char name[64]; 191 int ret; 192 193 ret = led_classdev_next_name(led_cdev->name, name, sizeof(name)); 194 if (ret < 0) 195 return ret; 196 197 led_cdev->dev = device_create_with_groups(leds_class, parent, 0, 198 led_cdev, led_cdev->groups, "%s", name); 199 if (IS_ERR(led_cdev->dev)) 200 return PTR_ERR(led_cdev->dev); 201 202 if (ret) 203 dev_warn(parent, "Led %s renamed to %s due to name collision", 204 led_cdev->name, dev_name(led_cdev->dev)); 205 206 #ifdef CONFIG_LEDS_TRIGGERS 207 init_rwsem(&led_cdev->trigger_lock); 208 #endif 209 mutex_init(&led_cdev->led_access); 210 /* add to the list of leds */ 211 down_write(&leds_list_lock); 212 list_add_tail(&led_cdev->node, &leds_list); 213 up_write(&leds_list_lock); 214 215 if (!led_cdev->max_brightness) 216 led_cdev->max_brightness = LED_FULL; 217 218 led_update_brightness(led_cdev); 219 220 led_init_core(led_cdev); 221 222 #ifdef CONFIG_LEDS_TRIGGERS 223 led_trigger_set_default(led_cdev); 224 #endif 225 226 dev_dbg(parent, "Registered led device: %s\n", 227 led_cdev->name); 228 229 return 0; 230 } 231 EXPORT_SYMBOL_GPL(led_classdev_register); 232 233 /** 234 * led_classdev_unregister - unregisters a object of led_properties class. 235 * @led_cdev: the led device to unregister 236 * 237 * Unregisters a previously registered via led_classdev_register object. 238 */ 239 void led_classdev_unregister(struct led_classdev *led_cdev) 240 { 241 #ifdef CONFIG_LEDS_TRIGGERS 242 down_write(&led_cdev->trigger_lock); 243 if (led_cdev->trigger) 244 led_trigger_set(led_cdev, NULL); 245 up_write(&led_cdev->trigger_lock); 246 #endif 247 248 led_cdev->flags |= LED_UNREGISTERING; 249 250 /* Stop blinking */ 251 led_stop_software_blink(led_cdev); 252 253 led_set_brightness(led_cdev, LED_OFF); 254 255 flush_work(&led_cdev->set_brightness_work); 256 257 device_unregister(led_cdev->dev); 258 259 down_write(&leds_list_lock); 260 list_del(&led_cdev->node); 261 up_write(&leds_list_lock); 262 263 mutex_destroy(&led_cdev->led_access); 264 } 265 EXPORT_SYMBOL_GPL(led_classdev_unregister); 266 267 static void devm_led_classdev_release(struct device *dev, void *res) 268 { 269 led_classdev_unregister(*(struct led_classdev **)res); 270 } 271 272 /** 273 * devm_led_classdev_register - resource managed led_classdev_register() 274 * @parent: The device to register. 275 * @led_cdev: the led_classdev structure for this device. 276 */ 277 int devm_led_classdev_register(struct device *parent, 278 struct led_classdev *led_cdev) 279 { 280 struct led_classdev **dr; 281 int rc; 282 283 dr = devres_alloc(devm_led_classdev_release, sizeof(*dr), GFP_KERNEL); 284 if (!dr) 285 return -ENOMEM; 286 287 rc = led_classdev_register(parent, led_cdev); 288 if (rc) { 289 devres_free(dr); 290 return rc; 291 } 292 293 *dr = led_cdev; 294 devres_add(parent, dr); 295 296 return 0; 297 } 298 EXPORT_SYMBOL_GPL(devm_led_classdev_register); 299 300 static int devm_led_classdev_match(struct device *dev, void *res, void *data) 301 { 302 struct led_cdev **p = res; 303 304 if (WARN_ON(!p || !*p)) 305 return 0; 306 307 return *p == data; 308 } 309 310 /** 311 * devm_led_classdev_unregister() - resource managed led_classdev_unregister() 312 * @parent: The device to unregister. 313 * @led_cdev: the led_classdev structure for this device. 314 */ 315 void devm_led_classdev_unregister(struct device *dev, 316 struct led_classdev *led_cdev) 317 { 318 WARN_ON(devres_release(dev, 319 devm_led_classdev_release, 320 devm_led_classdev_match, led_cdev)); 321 } 322 EXPORT_SYMBOL_GPL(devm_led_classdev_unregister); 323 324 static int __init leds_init(void) 325 { 326 leds_class = class_create(THIS_MODULE, "leds"); 327 if (IS_ERR(leds_class)) 328 return PTR_ERR(leds_class); 329 leds_class->pm = &leds_class_dev_pm_ops; 330 leds_class->dev_groups = led_groups; 331 return 0; 332 } 333 334 static void __exit leds_exit(void) 335 { 336 class_destroy(leds_class); 337 } 338 339 subsys_initcall(leds_init); 340 module_exit(leds_exit); 341 342 MODULE_AUTHOR("John Lenz, Richard Purdie"); 343 MODULE_LICENSE("GPL"); 344 MODULE_DESCRIPTION("LED Class Interface"); 345