David Brazdil | 0f672f6 | 2019-12-10 10:32:29 +0000 | [diff] [blame^] | 1 | // SPDX-License-Identifier: GPL-2.0-only |
Andrew Scull | b4b6d4a | 2019-01-02 15:54:55 +0000 | [diff] [blame] | 2 | /* |
| 3 | * LED Triggers Core |
| 4 | * |
| 5 | * Copyright 2005-2007 Openedhand Ltd. |
| 6 | * |
| 7 | * Author: Richard Purdie <rpurdie@openedhand.com> |
Andrew Scull | b4b6d4a | 2019-01-02 15:54:55 +0000 | [diff] [blame] | 8 | */ |
| 9 | |
| 10 | #include <linux/export.h> |
| 11 | #include <linux/kernel.h> |
| 12 | #include <linux/list.h> |
| 13 | #include <linux/spinlock.h> |
| 14 | #include <linux/device.h> |
| 15 | #include <linux/timer.h> |
| 16 | #include <linux/rwsem.h> |
| 17 | #include <linux/leds.h> |
| 18 | #include <linux/slab.h> |
| 19 | #include "leds.h" |
| 20 | |
| 21 | /* |
| 22 | * Nests outside led_cdev->trigger_lock |
| 23 | */ |
| 24 | static DECLARE_RWSEM(triggers_list_lock); |
| 25 | LIST_HEAD(trigger_list); |
| 26 | |
| 27 | /* Used by LED Class */ |
| 28 | |
| 29 | ssize_t led_trigger_store(struct device *dev, struct device_attribute *attr, |
| 30 | const char *buf, size_t count) |
| 31 | { |
| 32 | struct led_classdev *led_cdev = dev_get_drvdata(dev); |
| 33 | struct led_trigger *trig; |
| 34 | int ret = count; |
| 35 | |
| 36 | mutex_lock(&led_cdev->led_access); |
| 37 | |
| 38 | if (led_sysfs_is_disabled(led_cdev)) { |
| 39 | ret = -EBUSY; |
| 40 | goto unlock; |
| 41 | } |
| 42 | |
| 43 | if (sysfs_streq(buf, "none")) { |
| 44 | led_trigger_remove(led_cdev); |
| 45 | goto unlock; |
| 46 | } |
| 47 | |
| 48 | down_read(&triggers_list_lock); |
| 49 | list_for_each_entry(trig, &trigger_list, next_trig) { |
| 50 | if (sysfs_streq(buf, trig->name)) { |
| 51 | down_write(&led_cdev->trigger_lock); |
| 52 | led_trigger_set(led_cdev, trig); |
| 53 | up_write(&led_cdev->trigger_lock); |
| 54 | |
| 55 | up_read(&triggers_list_lock); |
| 56 | goto unlock; |
| 57 | } |
| 58 | } |
| 59 | /* we come here only if buf matches no trigger */ |
| 60 | ret = -EINVAL; |
| 61 | up_read(&triggers_list_lock); |
| 62 | |
| 63 | unlock: |
| 64 | mutex_unlock(&led_cdev->led_access); |
| 65 | return ret; |
| 66 | } |
| 67 | EXPORT_SYMBOL_GPL(led_trigger_store); |
| 68 | |
| 69 | ssize_t led_trigger_show(struct device *dev, struct device_attribute *attr, |
| 70 | char *buf) |
| 71 | { |
| 72 | struct led_classdev *led_cdev = dev_get_drvdata(dev); |
| 73 | struct led_trigger *trig; |
| 74 | int len = 0; |
| 75 | |
| 76 | down_read(&triggers_list_lock); |
| 77 | down_read(&led_cdev->trigger_lock); |
| 78 | |
| 79 | if (!led_cdev->trigger) |
| 80 | len += scnprintf(buf+len, PAGE_SIZE - len, "[none] "); |
| 81 | else |
| 82 | len += scnprintf(buf+len, PAGE_SIZE - len, "none "); |
| 83 | |
| 84 | list_for_each_entry(trig, &trigger_list, next_trig) { |
| 85 | if (led_cdev->trigger && !strcmp(led_cdev->trigger->name, |
| 86 | trig->name)) |
| 87 | len += scnprintf(buf+len, PAGE_SIZE - len, "[%s] ", |
| 88 | trig->name); |
| 89 | else |
| 90 | len += scnprintf(buf+len, PAGE_SIZE - len, "%s ", |
| 91 | trig->name); |
| 92 | } |
| 93 | up_read(&led_cdev->trigger_lock); |
| 94 | up_read(&triggers_list_lock); |
| 95 | |
| 96 | len += scnprintf(len+buf, PAGE_SIZE - len, "\n"); |
| 97 | return len; |
| 98 | } |
| 99 | EXPORT_SYMBOL_GPL(led_trigger_show); |
| 100 | |
| 101 | /* Caller must ensure led_cdev->trigger_lock held */ |
| 102 | int 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 | int ret; |
| 109 | |
| 110 | if (!led_cdev->trigger && !trig) |
| 111 | return 0; |
| 112 | |
| 113 | name = trig ? trig->name : "none"; |
| 114 | event = kasprintf(GFP_KERNEL, "TRIGGER=%s", name); |
| 115 | |
| 116 | /* Remove any existing trigger */ |
| 117 | if (led_cdev->trigger) { |
| 118 | write_lock_irqsave(&led_cdev->trigger->leddev_list_lock, flags); |
| 119 | list_del(&led_cdev->trig_list); |
| 120 | write_unlock_irqrestore(&led_cdev->trigger->leddev_list_lock, |
| 121 | flags); |
| 122 | cancel_work_sync(&led_cdev->set_brightness_work); |
| 123 | led_stop_software_blink(led_cdev); |
| 124 | if (led_cdev->trigger->deactivate) |
| 125 | led_cdev->trigger->deactivate(led_cdev); |
| 126 | device_remove_groups(led_cdev->dev, led_cdev->trigger->groups); |
| 127 | led_cdev->trigger = NULL; |
| 128 | led_cdev->trigger_data = NULL; |
| 129 | led_cdev->activated = false; |
| 130 | led_set_brightness(led_cdev, LED_OFF); |
| 131 | } |
| 132 | if (trig) { |
| 133 | write_lock_irqsave(&trig->leddev_list_lock, flags); |
| 134 | list_add_tail(&led_cdev->trig_list, &trig->led_cdevs); |
| 135 | write_unlock_irqrestore(&trig->leddev_list_lock, flags); |
| 136 | led_cdev->trigger = trig; |
| 137 | |
| 138 | if (trig->activate) |
| 139 | ret = trig->activate(led_cdev); |
| 140 | else |
| 141 | ret = 0; |
| 142 | |
| 143 | if (ret) |
| 144 | goto err_activate; |
| 145 | |
| 146 | ret = device_add_groups(led_cdev->dev, trig->groups); |
| 147 | if (ret) { |
| 148 | dev_err(led_cdev->dev, "Failed to add trigger attributes\n"); |
| 149 | goto err_add_groups; |
| 150 | } |
| 151 | } |
| 152 | |
| 153 | if (event) { |
| 154 | envp[0] = event; |
| 155 | envp[1] = NULL; |
| 156 | if (kobject_uevent_env(&led_cdev->dev->kobj, KOBJ_CHANGE, envp)) |
| 157 | dev_err(led_cdev->dev, |
| 158 | "%s: Error sending uevent\n", __func__); |
| 159 | kfree(event); |
| 160 | } |
| 161 | |
| 162 | return 0; |
| 163 | |
| 164 | err_add_groups: |
| 165 | |
| 166 | if (trig->deactivate) |
| 167 | trig->deactivate(led_cdev); |
| 168 | err_activate: |
| 169 | |
Andrew Scull | b4b6d4a | 2019-01-02 15:54:55 +0000 | [diff] [blame] | 170 | write_lock_irqsave(&led_cdev->trigger->leddev_list_lock, flags); |
| 171 | list_del(&led_cdev->trig_list); |
| 172 | write_unlock_irqrestore(&led_cdev->trigger->leddev_list_lock, flags); |
David Brazdil | 0f672f6 | 2019-12-10 10:32:29 +0000 | [diff] [blame^] | 173 | led_cdev->trigger = NULL; |
| 174 | led_cdev->trigger_data = NULL; |
Andrew Scull | b4b6d4a | 2019-01-02 15:54:55 +0000 | [diff] [blame] | 175 | led_set_brightness(led_cdev, LED_OFF); |
David Brazdil | 0f672f6 | 2019-12-10 10:32:29 +0000 | [diff] [blame^] | 176 | kfree(event); |
Andrew Scull | b4b6d4a | 2019-01-02 15:54:55 +0000 | [diff] [blame] | 177 | |
| 178 | return ret; |
| 179 | } |
| 180 | EXPORT_SYMBOL_GPL(led_trigger_set); |
| 181 | |
| 182 | void led_trigger_remove(struct led_classdev *led_cdev) |
| 183 | { |
| 184 | down_write(&led_cdev->trigger_lock); |
| 185 | led_trigger_set(led_cdev, NULL); |
| 186 | up_write(&led_cdev->trigger_lock); |
| 187 | } |
| 188 | EXPORT_SYMBOL_GPL(led_trigger_remove); |
| 189 | |
| 190 | void led_trigger_set_default(struct led_classdev *led_cdev) |
| 191 | { |
| 192 | struct led_trigger *trig; |
| 193 | |
| 194 | if (!led_cdev->default_trigger) |
| 195 | return; |
| 196 | |
| 197 | down_read(&triggers_list_lock); |
| 198 | down_write(&led_cdev->trigger_lock); |
| 199 | list_for_each_entry(trig, &trigger_list, next_trig) { |
David Brazdil | 0f672f6 | 2019-12-10 10:32:29 +0000 | [diff] [blame^] | 200 | if (!strcmp(led_cdev->default_trigger, trig->name)) { |
| 201 | led_cdev->flags |= LED_INIT_DEFAULT_TRIGGER; |
Andrew Scull | b4b6d4a | 2019-01-02 15:54:55 +0000 | [diff] [blame] | 202 | led_trigger_set(led_cdev, trig); |
David Brazdil | 0f672f6 | 2019-12-10 10:32:29 +0000 | [diff] [blame^] | 203 | break; |
| 204 | } |
Andrew Scull | b4b6d4a | 2019-01-02 15:54:55 +0000 | [diff] [blame] | 205 | } |
| 206 | up_write(&led_cdev->trigger_lock); |
| 207 | up_read(&triggers_list_lock); |
| 208 | } |
| 209 | EXPORT_SYMBOL_GPL(led_trigger_set_default); |
| 210 | |
| 211 | void led_trigger_rename_static(const char *name, struct led_trigger *trig) |
| 212 | { |
| 213 | /* new name must be on a temporary string to prevent races */ |
| 214 | BUG_ON(name == trig->name); |
| 215 | |
| 216 | down_write(&triggers_list_lock); |
| 217 | /* this assumes that trig->name was originaly allocated to |
| 218 | * non constant storage */ |
| 219 | strcpy((char *)trig->name, name); |
| 220 | up_write(&triggers_list_lock); |
| 221 | } |
| 222 | EXPORT_SYMBOL_GPL(led_trigger_rename_static); |
| 223 | |
| 224 | /* LED Trigger Interface */ |
| 225 | |
| 226 | int led_trigger_register(struct led_trigger *trig) |
| 227 | { |
| 228 | struct led_classdev *led_cdev; |
| 229 | struct led_trigger *_trig; |
| 230 | |
| 231 | rwlock_init(&trig->leddev_list_lock); |
| 232 | INIT_LIST_HEAD(&trig->led_cdevs); |
| 233 | |
| 234 | down_write(&triggers_list_lock); |
| 235 | /* Make sure the trigger's name isn't already in use */ |
| 236 | list_for_each_entry(_trig, &trigger_list, next_trig) { |
| 237 | if (!strcmp(_trig->name, trig->name)) { |
| 238 | up_write(&triggers_list_lock); |
| 239 | return -EEXIST; |
| 240 | } |
| 241 | } |
| 242 | /* Add to the list of led triggers */ |
| 243 | list_add_tail(&trig->next_trig, &trigger_list); |
| 244 | up_write(&triggers_list_lock); |
| 245 | |
| 246 | /* Register with any LEDs that have this as a default trigger */ |
| 247 | down_read(&leds_list_lock); |
| 248 | list_for_each_entry(led_cdev, &leds_list, node) { |
| 249 | down_write(&led_cdev->trigger_lock); |
| 250 | if (!led_cdev->trigger && led_cdev->default_trigger && |
David Brazdil | 0f672f6 | 2019-12-10 10:32:29 +0000 | [diff] [blame^] | 251 | !strcmp(led_cdev->default_trigger, trig->name)) { |
| 252 | led_cdev->flags |= LED_INIT_DEFAULT_TRIGGER; |
Andrew Scull | b4b6d4a | 2019-01-02 15:54:55 +0000 | [diff] [blame] | 253 | led_trigger_set(led_cdev, trig); |
David Brazdil | 0f672f6 | 2019-12-10 10:32:29 +0000 | [diff] [blame^] | 254 | } |
Andrew Scull | b4b6d4a | 2019-01-02 15:54:55 +0000 | [diff] [blame] | 255 | up_write(&led_cdev->trigger_lock); |
| 256 | } |
| 257 | up_read(&leds_list_lock); |
| 258 | |
| 259 | return 0; |
| 260 | } |
| 261 | EXPORT_SYMBOL_GPL(led_trigger_register); |
| 262 | |
| 263 | void led_trigger_unregister(struct led_trigger *trig) |
| 264 | { |
| 265 | struct led_classdev *led_cdev; |
| 266 | |
| 267 | if (list_empty_careful(&trig->next_trig)) |
| 268 | return; |
| 269 | |
| 270 | /* Remove from the list of led triggers */ |
| 271 | down_write(&triggers_list_lock); |
| 272 | list_del_init(&trig->next_trig); |
| 273 | up_write(&triggers_list_lock); |
| 274 | |
| 275 | /* Remove anyone actively using this trigger */ |
| 276 | down_read(&leds_list_lock); |
| 277 | list_for_each_entry(led_cdev, &leds_list, node) { |
| 278 | down_write(&led_cdev->trigger_lock); |
| 279 | if (led_cdev->trigger == trig) |
| 280 | led_trigger_set(led_cdev, NULL); |
| 281 | up_write(&led_cdev->trigger_lock); |
| 282 | } |
| 283 | up_read(&leds_list_lock); |
| 284 | } |
| 285 | EXPORT_SYMBOL_GPL(led_trigger_unregister); |
| 286 | |
| 287 | static void devm_led_trigger_release(struct device *dev, void *res) |
| 288 | { |
| 289 | led_trigger_unregister(*(struct led_trigger **)res); |
| 290 | } |
| 291 | |
| 292 | int devm_led_trigger_register(struct device *dev, |
| 293 | struct led_trigger *trig) |
| 294 | { |
| 295 | struct led_trigger **dr; |
| 296 | int rc; |
| 297 | |
| 298 | dr = devres_alloc(devm_led_trigger_release, sizeof(*dr), |
| 299 | GFP_KERNEL); |
| 300 | if (!dr) |
| 301 | return -ENOMEM; |
| 302 | |
| 303 | *dr = trig; |
| 304 | |
| 305 | rc = led_trigger_register(trig); |
| 306 | if (rc) |
| 307 | devres_free(dr); |
| 308 | else |
| 309 | devres_add(dev, dr); |
| 310 | |
| 311 | return rc; |
| 312 | } |
| 313 | EXPORT_SYMBOL_GPL(devm_led_trigger_register); |
| 314 | |
| 315 | /* Simple LED Tigger Interface */ |
| 316 | |
| 317 | void led_trigger_event(struct led_trigger *trig, |
| 318 | enum led_brightness brightness) |
| 319 | { |
| 320 | struct led_classdev *led_cdev; |
| 321 | |
| 322 | if (!trig) |
| 323 | return; |
| 324 | |
| 325 | read_lock(&trig->leddev_list_lock); |
| 326 | list_for_each_entry(led_cdev, &trig->led_cdevs, trig_list) |
| 327 | led_set_brightness(led_cdev, brightness); |
| 328 | read_unlock(&trig->leddev_list_lock); |
| 329 | } |
| 330 | EXPORT_SYMBOL_GPL(led_trigger_event); |
| 331 | |
| 332 | static void led_trigger_blink_setup(struct led_trigger *trig, |
| 333 | unsigned long *delay_on, |
| 334 | unsigned long *delay_off, |
| 335 | int oneshot, |
| 336 | int invert) |
| 337 | { |
| 338 | struct led_classdev *led_cdev; |
| 339 | |
| 340 | if (!trig) |
| 341 | return; |
| 342 | |
| 343 | read_lock(&trig->leddev_list_lock); |
| 344 | list_for_each_entry(led_cdev, &trig->led_cdevs, trig_list) { |
| 345 | if (oneshot) |
| 346 | led_blink_set_oneshot(led_cdev, delay_on, delay_off, |
| 347 | invert); |
| 348 | else |
| 349 | led_blink_set(led_cdev, delay_on, delay_off); |
| 350 | } |
| 351 | read_unlock(&trig->leddev_list_lock); |
| 352 | } |
| 353 | |
| 354 | void led_trigger_blink(struct led_trigger *trig, |
| 355 | unsigned long *delay_on, |
| 356 | unsigned long *delay_off) |
| 357 | { |
| 358 | led_trigger_blink_setup(trig, delay_on, delay_off, 0, 0); |
| 359 | } |
| 360 | EXPORT_SYMBOL_GPL(led_trigger_blink); |
| 361 | |
| 362 | void led_trigger_blink_oneshot(struct led_trigger *trig, |
| 363 | unsigned long *delay_on, |
| 364 | unsigned long *delay_off, |
| 365 | int invert) |
| 366 | { |
| 367 | led_trigger_blink_setup(trig, delay_on, delay_off, 1, invert); |
| 368 | } |
| 369 | EXPORT_SYMBOL_GPL(led_trigger_blink_oneshot); |
| 370 | |
| 371 | void led_trigger_register_simple(const char *name, struct led_trigger **tp) |
| 372 | { |
| 373 | struct led_trigger *trig; |
| 374 | int err; |
| 375 | |
| 376 | trig = kzalloc(sizeof(struct led_trigger), GFP_KERNEL); |
| 377 | |
| 378 | if (trig) { |
| 379 | trig->name = name; |
| 380 | err = led_trigger_register(trig); |
| 381 | if (err < 0) { |
| 382 | kfree(trig); |
| 383 | trig = NULL; |
| 384 | pr_warn("LED trigger %s failed to register (%d)\n", |
| 385 | name, err); |
| 386 | } |
| 387 | } else { |
| 388 | pr_warn("LED trigger %s failed to register (no memory)\n", |
| 389 | name); |
| 390 | } |
| 391 | *tp = trig; |
| 392 | } |
| 393 | EXPORT_SYMBOL_GPL(led_trigger_register_simple); |
| 394 | |
| 395 | void led_trigger_unregister_simple(struct led_trigger *trig) |
| 396 | { |
| 397 | if (trig) |
| 398 | led_trigger_unregister(trig); |
| 399 | kfree(trig); |
| 400 | } |
| 401 | EXPORT_SYMBOL_GPL(led_trigger_unregister_simple); |