| 1 | /* |
| 2 | * LED Triggers Core |
| 3 | * |
| 4 | * Copyright 2005-2007 Openedhand Ltd. |
| 5 | * |
| 6 | * Author: Richard Purdie <rpurdie@openedhand.com> |
| 7 | * |
| 8 | * This program is free software; you can redistribute it and/or modify |
| 9 | * it under the terms of the GNU General Public License version 2 as |
| 10 | * published by the Free Software Foundation. |
| 11 | * |
| 12 | */ |
| 13 | |
| 14 | #include <linux/module.h> |
| 15 | #include <linux/kernel.h> |
| 16 | #include <linux/list.h> |
| 17 | #include <linux/spinlock.h> |
| 18 | #include <linux/device.h> |
| 19 | #include <linux/timer.h> |
| 20 | #include <linux/rwsem.h> |
| 21 | #include <linux/leds.h> |
| 22 | #include <linux/slab.h> |
| 23 | #include "leds.h" |
| 24 | |
| 25 | /* |
| 26 | * Nests outside led_cdev->trigger_lock |
| 27 | */ |
| 28 | static DECLARE_RWSEM(triggers_list_lock); |
| 29 | static LIST_HEAD(trigger_list); |
| 30 | |
| 31 | /* Used by LED Class */ |
| 32 | |
| 33 | ssize_t led_trigger_store(struct device *dev, struct device_attribute *attr, |
| 34 | const char *buf, size_t count) |
| 35 | { |
| 36 | struct led_classdev *led_cdev = dev_get_drvdata(dev); |
| 37 | struct led_trigger *trig; |
| 38 | int ret = count; |
| 39 | |
| 40 | mutex_lock(&led_cdev->led_access); |
| 41 | |
| 42 | if (led_sysfs_is_disabled(led_cdev)) { |
| 43 | ret = -EBUSY; |
| 44 | goto unlock; |
| 45 | } |
| 46 | |
| 47 | if (sysfs_streq(buf, "none")) { |
| 48 | led_trigger_remove(led_cdev); |
| 49 | goto unlock; |
| 50 | } |
| 51 | |
| 52 | down_read(&triggers_list_lock); |
| 53 | list_for_each_entry(trig, &trigger_list, next_trig) { |
| 54 | if (sysfs_streq(buf, trig->name)) { |
| 55 | down_write(&led_cdev->trigger_lock); |
| 56 | led_trigger_set(led_cdev, trig); |
| 57 | up_write(&led_cdev->trigger_lock); |
| 58 | |
| 59 | up_read(&triggers_list_lock); |
| 60 | goto unlock; |
| 61 | } |
| 62 | } |
| 63 | up_read(&triggers_list_lock); |
| 64 | |
| 65 | unlock: |
| 66 | mutex_unlock(&led_cdev->led_access); |
| 67 | return ret; |
| 68 | } |
| 69 | EXPORT_SYMBOL_GPL(led_trigger_store); |
| 70 | |
| 71 | ssize_t led_trigger_show(struct device *dev, struct device_attribute *attr, |
| 72 | char *buf) |
| 73 | { |
| 74 | struct led_classdev *led_cdev = dev_get_drvdata(dev); |
| 75 | struct led_trigger *trig; |
| 76 | int len = 0; |
| 77 | |
| 78 | down_read(&triggers_list_lock); |
| 79 | down_read(&led_cdev->trigger_lock); |
| 80 | |
| 81 | if (!led_cdev->trigger) |
| 82 | len += sprintf(buf+len, "[none] "); |
| 83 | else |
| 84 | len += sprintf(buf+len, "none "); |
| 85 | |
| 86 | list_for_each_entry(trig, &trigger_list, next_trig) { |
| 87 | if (led_cdev->trigger && !strcmp(led_cdev->trigger->name, |
| 88 | trig->name)) |
| 89 | len += sprintf(buf+len, "[%s] ", trig->name); |
| 90 | else |
| 91 | len += sprintf(buf+len, "%s ", trig->name); |
| 92 | } |
| 93 | up_read(&led_cdev->trigger_lock); |
| 94 | up_read(&triggers_list_lock); |
| 95 | |
| 96 | len += sprintf(len+buf, "\n"); |
| 97 | return len; |
| 98 | } |
| 99 | EXPORT_SYMBOL_GPL(led_trigger_show); |
| 100 | |
| 101 | /* Caller must ensure led_cdev->trigger_lock held */ |
| 102 | void led_trigger_set(struct led_classdev *led_cdev, struct led_trigger *trig) |
| 103 | { |
| 104 | unsigned long flags; |
| 105 | char *event = NULL; |
| 106 | char *envp[2]; |
| 107 | const char *name; |
| 108 | |
| 109 | name = trig ? trig->name : "none"; |
| 110 | event = kasprintf(GFP_KERNEL, "TRIGGER=%s", name); |
| 111 | |
| 112 | /* Remove any existing trigger */ |
| 113 | if (led_cdev->trigger) { |
| 114 | write_lock_irqsave(&led_cdev->trigger->leddev_list_lock, flags); |
| 115 | list_del(&led_cdev->trig_list); |
| 116 | write_unlock_irqrestore(&led_cdev->trigger->leddev_list_lock, |
| 117 | flags); |
| 118 | cancel_work_sync(&led_cdev->set_brightness_work); |
| 119 | led_stop_software_blink(led_cdev); |
| 120 | if (led_cdev->trigger->deactivate) |
| 121 | led_cdev->trigger->deactivate(led_cdev); |
| 122 | led_cdev->trigger = NULL; |
| 123 | led_set_brightness(led_cdev, LED_OFF); |
| 124 | } |
| 125 | if (trig) { |
| 126 | write_lock_irqsave(&trig->leddev_list_lock, flags); |
| 127 | list_add_tail(&led_cdev->trig_list, &trig->led_cdevs); |
| 128 | write_unlock_irqrestore(&trig->leddev_list_lock, flags); |
| 129 | led_cdev->trigger = trig; |
| 130 | if (trig->activate) |
| 131 | trig->activate(led_cdev); |
| 132 | } |
| 133 | |
| 134 | if (event) { |
| 135 | envp[0] = event; |
| 136 | envp[1] = NULL; |
| 137 | kobject_uevent_env(&led_cdev->dev->kobj, KOBJ_CHANGE, envp); |
| 138 | kfree(event); |
| 139 | } |
| 140 | } |
| 141 | EXPORT_SYMBOL_GPL(led_trigger_set); |
| 142 | |
| 143 | void led_trigger_remove(struct led_classdev *led_cdev) |
| 144 | { |
| 145 | down_write(&led_cdev->trigger_lock); |
| 146 | led_trigger_set(led_cdev, NULL); |
| 147 | up_write(&led_cdev->trigger_lock); |
| 148 | } |
| 149 | EXPORT_SYMBOL_GPL(led_trigger_remove); |
| 150 | |
| 151 | void led_trigger_set_default(struct led_classdev *led_cdev) |
| 152 | { |
| 153 | struct led_trigger *trig; |
| 154 | |
| 155 | if (!led_cdev->default_trigger) |
| 156 | return; |
| 157 | |
| 158 | down_read(&triggers_list_lock); |
| 159 | down_write(&led_cdev->trigger_lock); |
| 160 | list_for_each_entry(trig, &trigger_list, next_trig) { |
| 161 | if (!strcmp(led_cdev->default_trigger, trig->name)) |
| 162 | led_trigger_set(led_cdev, trig); |
| 163 | } |
| 164 | up_write(&led_cdev->trigger_lock); |
| 165 | up_read(&triggers_list_lock); |
| 166 | } |
| 167 | EXPORT_SYMBOL_GPL(led_trigger_set_default); |
| 168 | |
| 169 | void led_trigger_rename_static(const char *name, struct led_trigger *trig) |
| 170 | { |
| 171 | /* new name must be on a temporary string to prevent races */ |
| 172 | BUG_ON(name == trig->name); |
| 173 | |
| 174 | down_write(&triggers_list_lock); |
| 175 | /* this assumes that trig->name was originaly allocated to |
| 176 | * non constant storage */ |
| 177 | strcpy((char *)trig->name, name); |
| 178 | up_write(&triggers_list_lock); |
| 179 | } |
| 180 | EXPORT_SYMBOL_GPL(led_trigger_rename_static); |
| 181 | |
| 182 | /* LED Trigger Interface */ |
| 183 | |
| 184 | int led_trigger_register(struct led_trigger *trig) |
| 185 | { |
| 186 | struct led_classdev *led_cdev; |
| 187 | struct led_trigger *_trig; |
| 188 | |
| 189 | rwlock_init(&trig->leddev_list_lock); |
| 190 | INIT_LIST_HEAD(&trig->led_cdevs); |
| 191 | |
| 192 | down_write(&triggers_list_lock); |
| 193 | /* Make sure the trigger's name isn't already in use */ |
| 194 | list_for_each_entry(_trig, &trigger_list, next_trig) { |
| 195 | if (!strcmp(_trig->name, trig->name)) { |
| 196 | up_write(&triggers_list_lock); |
| 197 | return -EEXIST; |
| 198 | } |
| 199 | } |
| 200 | /* Add to the list of led triggers */ |
| 201 | list_add_tail(&trig->next_trig, &trigger_list); |
| 202 | up_write(&triggers_list_lock); |
| 203 | |
| 204 | /* Register with any LEDs that have this as a default trigger */ |
| 205 | down_read(&leds_list_lock); |
| 206 | list_for_each_entry(led_cdev, &leds_list, node) { |
| 207 | down_write(&led_cdev->trigger_lock); |
| 208 | if (!led_cdev->trigger && led_cdev->default_trigger && |
| 209 | !strcmp(led_cdev->default_trigger, trig->name)) |
| 210 | led_trigger_set(led_cdev, trig); |
| 211 | up_write(&led_cdev->trigger_lock); |
| 212 | } |
| 213 | up_read(&leds_list_lock); |
| 214 | |
| 215 | return 0; |
| 216 | } |
| 217 | EXPORT_SYMBOL_GPL(led_trigger_register); |
| 218 | |
| 219 | void led_trigger_unregister(struct led_trigger *trig) |
| 220 | { |
| 221 | struct led_classdev *led_cdev; |
| 222 | |
| 223 | if (list_empty_careful(&trig->next_trig)) |
| 224 | return; |
| 225 | |
| 226 | /* Remove from the list of led triggers */ |
| 227 | down_write(&triggers_list_lock); |
| 228 | list_del_init(&trig->next_trig); |
| 229 | up_write(&triggers_list_lock); |
| 230 | |
| 231 | /* Remove anyone actively using this trigger */ |
| 232 | down_read(&leds_list_lock); |
| 233 | list_for_each_entry(led_cdev, &leds_list, node) { |
| 234 | down_write(&led_cdev->trigger_lock); |
| 235 | if (led_cdev->trigger == trig) |
| 236 | led_trigger_set(led_cdev, NULL); |
| 237 | up_write(&led_cdev->trigger_lock); |
| 238 | } |
| 239 | up_read(&leds_list_lock); |
| 240 | } |
| 241 | EXPORT_SYMBOL_GPL(led_trigger_unregister); |
| 242 | |
| 243 | static void devm_led_trigger_release(struct device *dev, void *res) |
| 244 | { |
| 245 | led_trigger_unregister(*(struct led_trigger **)res); |
| 246 | } |
| 247 | |
| 248 | int devm_led_trigger_register(struct device *dev, |
| 249 | struct led_trigger *trig) |
| 250 | { |
| 251 | struct led_trigger **dr; |
| 252 | int rc; |
| 253 | |
| 254 | dr = devres_alloc(devm_led_trigger_release, sizeof(*dr), |
| 255 | GFP_KERNEL); |
| 256 | if (!dr) |
| 257 | return -ENOMEM; |
| 258 | |
| 259 | *dr = trig; |
| 260 | |
| 261 | rc = led_trigger_register(trig); |
| 262 | if (rc) |
| 263 | devres_free(dr); |
| 264 | else |
| 265 | devres_add(dev, dr); |
| 266 | |
| 267 | return rc; |
| 268 | } |
| 269 | EXPORT_SYMBOL_GPL(devm_led_trigger_register); |
| 270 | |
| 271 | /* Simple LED Tigger Interface */ |
| 272 | |
| 273 | void led_trigger_event(struct led_trigger *trig, |
| 274 | enum led_brightness brightness) |
| 275 | { |
| 276 | struct led_classdev *led_cdev; |
| 277 | |
| 278 | if (!trig) |
| 279 | return; |
| 280 | |
| 281 | read_lock(&trig->leddev_list_lock); |
| 282 | list_for_each_entry(led_cdev, &trig->led_cdevs, trig_list) |
| 283 | led_set_brightness(led_cdev, brightness); |
| 284 | read_unlock(&trig->leddev_list_lock); |
| 285 | } |
| 286 | EXPORT_SYMBOL_GPL(led_trigger_event); |
| 287 | |
| 288 | static void led_trigger_blink_setup(struct led_trigger *trig, |
| 289 | unsigned long *delay_on, |
| 290 | unsigned long *delay_off, |
| 291 | int oneshot, |
| 292 | int invert) |
| 293 | { |
| 294 | struct led_classdev *led_cdev; |
| 295 | |
| 296 | if (!trig) |
| 297 | return; |
| 298 | |
| 299 | read_lock(&trig->leddev_list_lock); |
| 300 | list_for_each_entry(led_cdev, &trig->led_cdevs, trig_list) { |
| 301 | if (oneshot) |
| 302 | led_blink_set_oneshot(led_cdev, delay_on, delay_off, |
| 303 | invert); |
| 304 | else |
| 305 | led_blink_set(led_cdev, delay_on, delay_off); |
| 306 | } |
| 307 | read_unlock(&trig->leddev_list_lock); |
| 308 | } |
| 309 | |
| 310 | void led_trigger_blink(struct led_trigger *trig, |
| 311 | unsigned long *delay_on, |
| 312 | unsigned long *delay_off) |
| 313 | { |
| 314 | led_trigger_blink_setup(trig, delay_on, delay_off, 0, 0); |
| 315 | } |
| 316 | EXPORT_SYMBOL_GPL(led_trigger_blink); |
| 317 | |
| 318 | void led_trigger_blink_oneshot(struct led_trigger *trig, |
| 319 | unsigned long *delay_on, |
| 320 | unsigned long *delay_off, |
| 321 | int invert) |
| 322 | { |
| 323 | led_trigger_blink_setup(trig, delay_on, delay_off, 1, invert); |
| 324 | } |
| 325 | EXPORT_SYMBOL_GPL(led_trigger_blink_oneshot); |
| 326 | |
| 327 | void led_trigger_register_simple(const char *name, struct led_trigger **tp) |
| 328 | { |
| 329 | struct led_trigger *trig; |
| 330 | int err; |
| 331 | |
| 332 | trig = kzalloc(sizeof(struct led_trigger), GFP_KERNEL); |
| 333 | |
| 334 | if (trig) { |
| 335 | trig->name = name; |
| 336 | err = led_trigger_register(trig); |
| 337 | if (err < 0) { |
| 338 | kfree(trig); |
| 339 | trig = NULL; |
| 340 | pr_warn("LED trigger %s failed to register (%d)\n", |
| 341 | name, err); |
| 342 | } |
| 343 | } else { |
| 344 | pr_warn("LED trigger %s failed to register (no memory)\n", |
| 345 | name); |
| 346 | } |
| 347 | *tp = trig; |
| 348 | } |
| 349 | EXPORT_SYMBOL_GPL(led_trigger_register_simple); |
| 350 | |
| 351 | void led_trigger_unregister_simple(struct led_trigger *trig) |
| 352 | { |
| 353 | if (trig) |
| 354 | led_trigger_unregister(trig); |
| 355 | kfree(trig); |
| 356 | } |
| 357 | EXPORT_SYMBOL_GPL(led_trigger_unregister_simple); |
| 358 | |
| 359 | MODULE_AUTHOR("Richard Purdie"); |
| 360 | MODULE_LICENSE("GPL"); |
| 361 | MODULE_DESCRIPTION("LED Triggers Core"); |