drivers/leds/led-core.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * LED Class Core
   4  *
   5  * Copyright 2005-2006 Openedhand Ltd.
   6  *
   7  * Author: Richard Purdie <rpurdie@openedhand.com>
   8  */
   9
  10 #include <linux/kernel.h>
  11 #include <linux/leds.h>
  12 #include <linux/list.h>
  13 #include <linux/module.h>
  14 #include <linux/mutex.h>
  15 #include <linux/of.h>
  16 #include <linux/property.h>
  17 #include <linux/rwsem.h>
  18 #include <linux/slab.h>
  19 #include <uapi/linux/uleds.h>
  20 #include "leds.h"
  21
  22 DECLARE_RWSEM(leds_list_lock);
  23 EXPORT_SYMBOL_GPL(leds_list_lock);
  24
  25 LIST_HEAD(leds_list);
  26 EXPORT_SYMBOL_GPL(leds_list);
  27
  28 const char * const led_colors[LED_COLOR_ID_MAX] = {
  29         [LED_COLOR_ID_WHITE] = "white",
  30         [LED_COLOR_ID_RED] = "red",
  31         [LED_COLOR_ID_GREEN] = "green",
  32         [LED_COLOR_ID_BLUE] = "blue",
  33         [LED_COLOR_ID_AMBER] = "amber",
  34         [LED_COLOR_ID_VIOLET] = "violet",
  35         [LED_COLOR_ID_YELLOW] = "yellow",
  36         [LED_COLOR_ID_IR] = "ir",
  37         [LED_COLOR_ID_MULTI] = "multicolor",
  38         [LED_COLOR_ID_RGB] = "rgb",
  39 };
  40 EXPORT_SYMBOL_GPL(led_colors);
  41
  42 static int __led_set_brightness(struct led_classdev *led_cdev, unsigned int value)
  43 {
  44         if (!led_cdev->brightness_set)
  45                 return -ENOTSUPP;
  46
  47         led_cdev->brightness_set(led_cdev, value);
  48
  49         return 0;
  50 }
  51
  52 static int __led_set_brightness_blocking(struct led_classdev *led_cdev, unsigned int value)
  53 {
  54         if (!led_cdev->brightness_set_blocking)
  55                 return -ENOTSUPP;
  56
  57         return led_cdev->brightness_set_blocking(led_cdev, value);
  58 }
  59
  60 static void led_timer_function(struct timer_list *t)
  61 {
  62         struct led_classdev *led_cdev = from_timer(led_cdev, t, blink_timer);
  63         unsigned long brightness;
  64         unsigned long delay;
  65
  66         if (!led_cdev->blink_delay_on || !led_cdev->blink_delay_off) {
  67                 led_set_brightness_nosleep(led_cdev, LED_OFF);
  68                 clear_bit(LED_BLINK_SW, &led_cdev->work_flags);
  69                 return;
  70         }
  71
  72         if (test_and_clear_bit(LED_BLINK_ONESHOT_STOP,
  73                                &led_cdev->work_flags)) {
  74                 clear_bit(LED_BLINK_SW, &led_cdev->work_flags);
  75                 return;
  76         }
  77
  78         brightness = led_get_brightness(led_cdev);
  79         if (!brightness) {
  80                 /* Time to switch the LED on. */
  81                 if (test_and_clear_bit(LED_BLINK_BRIGHTNESS_CHANGE,
  82                                         &led_cdev->work_flags))
  83                         brightness = led_cdev->new_blink_brightness;
  84                 else
  85                         brightness = led_cdev->blink_brightness;
  86                 delay = led_cdev->blink_delay_on;
  87         } else {
  88                 /* Store the current brightness value to be able
  89                  * to restore it when the delay_off period is over.
  90                  */
  91                 led_cdev->blink_brightness = brightness;
  92                 brightness = LED_OFF;
  93                 delay = led_cdev->blink_delay_off;
  94         }
  95
  96         led_set_brightness_nosleep(led_cdev, brightness);
  97
  98         /* Return in next iteration if led is in one-shot mode and we are in
  99          * the final blink state so that the led is toggled each delay_on +
 100          * delay_off milliseconds in worst case.
 101          */
 102         if (test_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags)) {
 103                 if (test_bit(LED_BLINK_INVERT, &led_cdev->work_flags)) {
 104                         if (brightness)
 105                                 set_bit(LED_BLINK_ONESHOT_STOP,
 106                                         &led_cdev->work_flags);
 107                 } else {
 108                         if (!brightness)
 109                                 set_bit(LED_BLINK_ONESHOT_STOP,
 110                                         &led_cdev->work_flags);
 111                 }
 112         }
 113
 114         mod_timer(&led_cdev->blink_timer, jiffies + msecs_to_jiffies(delay));
 115 }
 116
 117 static void set_brightness_delayed_set_brightness(struct led_classdev *led_cdev,
 118                                                   unsigned int value)
 119 {
 120         int ret = 0;
 121
 122         ret = __led_set_brightness(led_cdev, value);
 123         if (ret == -ENOTSUPP)
 124                 ret = __led_set_brightness_blocking(led_cdev, value);
 125         if (ret < 0 &&
 126             /* LED HW might have been unplugged, therefore don't warn */
 127             !(ret == -ENODEV && (led_cdev->flags & LED_UNREGISTERING) &&
 128             (led_cdev->flags & LED_HW_PLUGGABLE)))
 129                 dev_err(led_cdev->dev,
 130                         "Setting an LED's brightness failed (%d)\n", ret);
 131 }
 132
 133 static void set_brightness_delayed(struct work_struct *ws)
 134 {
 135         struct led_classdev *led_cdev =
 136                 container_of(ws, struct led_classdev, set_brightness_work);
 137
 138         if (test_and_clear_bit(LED_BLINK_DISABLE, &led_cdev->work_flags)) {
 139                 led_stop_software_blink(led_cdev);
 140                 set_bit(LED_SET_BRIGHTNESS_OFF, &led_cdev->work_flags);
 141         }
 142
 143         /*
 144          * Triggers may call led_set_brightness(LED_OFF),
 145          * led_set_brightness(LED_FULL) in quick succession to disable blinking
 146          * and turn the LED on. Both actions may have been scheduled to run
 147          * before this work item runs once. To make sure this works properly
 148          * handle LED_SET_BRIGHTNESS_OFF first.
 149          */
 150         if (test_and_clear_bit(LED_SET_BRIGHTNESS_OFF, &led_cdev->work_flags))
 151                 set_brightness_delayed_set_brightness(led_cdev, LED_OFF);
 152
 153         if (test_and_clear_bit(LED_SET_BRIGHTNESS, &led_cdev->work_flags))
 154                 set_brightness_delayed_set_brightness(led_cdev, led_cdev->delayed_set_value);
 155
 156         if (test_and_clear_bit(LED_SET_BLINK, &led_cdev->work_flags)) {
 157                 unsigned long delay_on = led_cdev->delayed_delay_on;
 158                 unsigned long delay_off = led_cdev->delayed_delay_off;
 159
 160                 led_blink_set(led_cdev, &delay_on, &delay_off);
 161         }
 162 }
 163
 164 static void led_set_software_blink(struct led_classdev *led_cdev,
 165                                    unsigned long delay_on,
 166                                    unsigned long delay_off)
 167 {
 168         int current_brightness;
 169
 170         current_brightness = led_get_brightness(led_cdev);
 171         if (current_brightness)
 172                 led_cdev->blink_brightness = current_brightness;
 173         if (!led_cdev->blink_brightness)
 174                 led_cdev->blink_brightness = led_cdev->max_brightness;
 175
 176         led_cdev->blink_delay_on = delay_on;
 177         led_cdev->blink_delay_off = delay_off;
 178
 179         /* never on - just set to off */
 180         if (!delay_on) {
 181                 led_set_brightness_nosleep(led_cdev, LED_OFF);
 182                 return;
 183         }
 184
 185         /* never off - just set to brightness */
 186         if (!delay_off) {
 187                 led_set_brightness_nosleep(led_cdev,
 188                                            led_cdev->blink_brightness);
 189                 return;
 190         }
 191
 192         set_bit(LED_BLINK_SW, &led_cdev->work_flags);
 193         mod_timer(&led_cdev->blink_timer, jiffies + 1);
 194 }
 195
 196
 197 static void led_blink_setup(struct led_classdev *led_cdev,
 198                      unsigned long *delay_on,
 199                      unsigned long *delay_off)
 200 {
 201         if (!test_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags) &&
 202             led_cdev->blink_set &&
 203             !led_cdev->blink_set(led_cdev, delay_on, delay_off))
 204                 return;
 205
 206         /* blink with 1 Hz as default if nothing specified */
 207         if (!*delay_on && !*delay_off)
 208                 *delay_on = *delay_off = 500;
 209
 210         led_set_software_blink(led_cdev, *delay_on, *delay_off);
 211 }
 212
 213 void led_init_core(struct led_classdev *led_cdev)
 214 {
 215         INIT_WORK(&led_cdev->set_brightness_work, set_brightness_delayed);
 216
 217         timer_setup(&led_cdev->blink_timer, led_timer_function, 0);
 218 }
 219 EXPORT_SYMBOL_GPL(led_init_core);
 220
 221 void led_blink_set(struct led_classdev *led_cdev,
 222                    unsigned long *delay_on,
 223                    unsigned long *delay_off)
 224 {
 225         del_timer_sync(&led_cdev->blink_timer);
 226
 227         clear_bit(LED_BLINK_SW, &led_cdev->work_flags);
 228         clear_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags);
 229         clear_bit(LED_BLINK_ONESHOT_STOP, &led_cdev->work_flags);
 230
 231         led_blink_setup(led_cdev, delay_on, delay_off);
 232 }
 233 EXPORT_SYMBOL_GPL(led_blink_set);
 234
 235 void led_blink_set_oneshot(struct led_classdev *led_cdev,
 236                            unsigned long *delay_on,
 237                            unsigned long *delay_off,
 238                            int invert)
 239 {
 240         if (test_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags) &&
 241              timer_pending(&led_cdev->blink_timer))
 242                 return;
 243
 244         set_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags);
 245         clear_bit(LED_BLINK_ONESHOT_STOP, &led_cdev->work_flags);
 246
 247         if (invert)
 248                 set_bit(LED_BLINK_INVERT, &led_cdev->work_flags);
 249         else
 250                 clear_bit(LED_BLINK_INVERT, &led_cdev->work_flags);
 251
 252         led_blink_setup(led_cdev, delay_on, delay_off);
 253 }
 254 EXPORT_SYMBOL_GPL(led_blink_set_oneshot);
 255
 256 void led_blink_set_nosleep(struct led_classdev *led_cdev, unsigned long delay_on,
 257                            unsigned long delay_off)
 258 {
 259         /* If necessary delegate to a work queue task. */
 260         if (led_cdev->blink_set && led_cdev->brightness_set_blocking) {
 261                 led_cdev->delayed_delay_on = delay_on;
 262                 led_cdev->delayed_delay_off = delay_off;
 263                 set_bit(LED_SET_BLINK, &led_cdev->work_flags);
 264                 schedule_work(&led_cdev->set_brightness_work);
 265                 return;
 266         }
 267
 268         led_blink_set(led_cdev, &delay_on, &delay_off);
 269 }
 270 EXPORT_SYMBOL_GPL(led_blink_set_nosleep);
 271
 272 void led_stop_software_blink(struct led_classdev *led_cdev)
 273 {
 274         del_timer_sync(&led_cdev->blink_timer);
 275         led_cdev->blink_delay_on = 0;
 276         led_cdev->blink_delay_off = 0;
 277         clear_bit(LED_BLINK_SW, &led_cdev->work_flags);
 278 }
 279 EXPORT_SYMBOL_GPL(led_stop_software_blink);
 280
 281 void led_set_brightness(struct led_classdev *led_cdev, unsigned int brightness)
 282 {
 283         /*
 284          * If software blink is active, delay brightness setting
 285          * until the next timer tick.
 286          */
 287         if (test_bit(LED_BLINK_SW, &led_cdev->work_flags)) {
 288                 /*
 289                  * If we need to disable soft blinking delegate this to the
 290                  * work queue task to avoid problems in case we are called
 291                  * from hard irq context.
 292                  */
 293                 if (!brightness) {
 294                         set_bit(LED_BLINK_DISABLE, &led_cdev->work_flags);
 295                         schedule_work(&led_cdev->set_brightness_work);
 296                 } else {
 297                         set_bit(LED_BLINK_BRIGHTNESS_CHANGE,
 298                                 &led_cdev->work_flags);
 299                         led_cdev->new_blink_brightness = brightness;
 300                 }
 301                 return;
 302         }
 303
 304         led_set_brightness_nosleep(led_cdev, brightness);
 305 }
 306 EXPORT_SYMBOL_GPL(led_set_brightness);
 307
 308 void led_set_brightness_nopm(struct led_classdev *led_cdev, unsigned int value)
 309 {
 310         /* Use brightness_set op if available, it is guaranteed not to sleep */
 311         if (!__led_set_brightness(led_cdev, value))
 312                 return;
 313
 314         /*
 315          * Brightness setting can sleep, delegate it to a work queue task.
 316          * value 0 / LED_OFF is special, since it also disables hw-blinking
 317          * (sw-blink disable is handled in led_set_brightness()).
 318          * To avoid a hw-blink-disable getting lost when a second brightness
 319          * change is done immediately afterwards (before the work runs),
 320          * it uses a separate work_flag.
 321          */
 322         if (value) {
 323                 led_cdev->delayed_set_value = value;
 324                 set_bit(LED_SET_BRIGHTNESS, &led_cdev->work_flags);
 325         } else {
 326                 clear_bit(LED_SET_BRIGHTNESS, &led_cdev->work_flags);
 327                 clear_bit(LED_SET_BLINK, &led_cdev->work_flags);
 328                 set_bit(LED_SET_BRIGHTNESS_OFF, &led_cdev->work_flags);
 329         }
 330
 331         schedule_work(&led_cdev->set_brightness_work);
 332 }
 333 EXPORT_SYMBOL_GPL(led_set_brightness_nopm);
 334
 335 void led_set_brightness_nosleep(struct led_classdev *led_cdev, unsigned int value)
 336 {
 337         led_cdev->brightness = min(value, led_cdev->max_brightness);
 338
 339         if (led_cdev->flags & LED_SUSPENDED)
 340                 return;
 341
 342         led_set_brightness_nopm(led_cdev, led_cdev->brightness);
 343 }
 344 EXPORT_SYMBOL_GPL(led_set_brightness_nosleep);
 345
 346 int led_set_brightness_sync(struct led_classdev *led_cdev, unsigned int value)
 347 {
 348         if (led_cdev->blink_delay_on || led_cdev->blink_delay_off)
 349                 return -EBUSY;
 350
 351         led_cdev->brightness = min(value, led_cdev->max_brightness);
 352
 353         if (led_cdev->flags & LED_SUSPENDED)
 354                 return 0;
 355
 356         return __led_set_brightness_blocking(led_cdev, led_cdev->brightness);
 357 }
 358 EXPORT_SYMBOL_GPL(led_set_brightness_sync);
 359
 360 int led_update_brightness(struct led_classdev *led_cdev)
 361 {
 362         int ret = 0;
 363
 364         if (led_cdev->brightness_get) {
 365                 ret = led_cdev->brightness_get(led_cdev);
 366                 if (ret >= 0) {
 367                         led_cdev->brightness = ret;
 368                         return 0;
 369                 }
 370         }
 371
 372         return ret;
 373 }
 374 EXPORT_SYMBOL_GPL(led_update_brightness);
 375
 376 u32 *led_get_default_pattern(struct led_classdev *led_cdev, unsigned int *size)
 377 {
 378         struct fwnode_handle *fwnode = led_cdev->dev->fwnode;
 379         u32 *pattern;
 380         int count;
 381
 382         count = fwnode_property_count_u32(fwnode, "led-pattern");
 383         if (count < 0)
 384                 return NULL;
 385
 386         pattern = kcalloc(count, sizeof(*pattern), GFP_KERNEL);
 387         if (!pattern)
 388                 return NULL;
 389
 390         if (fwnode_property_read_u32_array(fwnode, "led-pattern", pattern, count)) {
 391                 kfree(pattern);
 392                 return NULL;
 393         }
 394
 395         *size = count;
 396
 397         return pattern;
 398 }
 399 EXPORT_SYMBOL_GPL(led_get_default_pattern);
 400
 401 /* Caller must ensure led_cdev->led_access held */
 402 void led_sysfs_disable(struct led_classdev *led_cdev)
 403 {
 404         lockdep_assert_held(&led_cdev->led_access);
 405
 406         led_cdev->flags |= LED_SYSFS_DISABLE;
 407 }
 408 EXPORT_SYMBOL_GPL(led_sysfs_disable);
 409
 410 /* Caller must ensure led_cdev->led_access held */
 411 void led_sysfs_enable(struct led_classdev *led_cdev)
 412 {
 413         lockdep_assert_held(&led_cdev->led_access);
 414
 415         led_cdev->flags &= ~LED_SYSFS_DISABLE;
 416 }
 417 EXPORT_SYMBOL_GPL(led_sysfs_enable);
 418
 419 static void led_parse_fwnode_props(struct device *dev,
 420                                    struct fwnode_handle *fwnode,
 421                                    struct led_properties *props)
 422 {
 423         int ret;
 424
 425         if (!fwnode)
 426                 return;
 427
 428         if (fwnode_property_present(fwnode, "label")) {
 429                 ret = fwnode_property_read_string(fwnode, "label", &props->label);
 430                 if (ret)
 431                         dev_err(dev, "Error parsing 'label' property (%d)\n", ret);
 432                 return;
 433         }
 434
 435         if (fwnode_property_present(fwnode, "color")) {
 436                 ret = fwnode_property_read_u32(fwnode, "color", &props->color);
 437                 if (ret)
 438                         dev_err(dev, "Error parsing 'color' property (%d)\n", ret);
 439                 else if (props->color >= LED_COLOR_ID_MAX)
 440                         dev_err(dev, "LED color identifier out of range\n");
 441                 else
 442                         props->color_present = true;
 443         }
 444
 445
 446         if (!fwnode_property_present(fwnode, "function"))
 447                 return;
 448
 449         ret = fwnode_property_read_string(fwnode, "function", &props->function);
 450         if (ret) {
 451                 dev_err(dev,
 452                         "Error parsing 'function' property (%d)\n",
 453                         ret);
 454         }
 455
 456         if (!fwnode_property_present(fwnode, "function-enumerator"))
 457                 return;
 458
 459         ret = fwnode_property_read_u32(fwnode, "function-enumerator",
 460                                        &props->func_enum);
 461         if (ret) {
 462                 dev_err(dev,
 463                         "Error parsing 'function-enumerator' property (%d)\n",
 464                         ret);
 465         } else {
 466                 props->func_enum_present = true;
 467         }
 468 }
 469
 470 int led_compose_name(struct device *dev, struct led_init_data *init_data,
 471                      char *led_classdev_name)
 472 {
 473         struct led_properties props = {};
 474         struct fwnode_handle *fwnode = init_data->fwnode;
 475         const char *devicename = init_data->devicename;
 476
 477         if (!led_classdev_name)
 478                 return -EINVAL;
 479
 480         led_parse_fwnode_props(dev, fwnode, &props);
 481
 482         if (props.label) {
 483                 /*
 484                  * If init_data.devicename is NULL, then it indicates that
 485                  * DT label should be used as-is for LED class device name.
 486                  * Otherwise the label is prepended with devicename to compose
 487                  * the final LED class device name.
 488                  */
 489                 if (!devicename) {
 490                         strscpy(led_classdev_name, props.label,
 491                                 LED_MAX_NAME_SIZE);
 492                 } else {
 493                         snprintf(led_classdev_name, LED_MAX_NAME_SIZE, "%s:%s",
 494                                  devicename, props.label);
 495                 }
 496         } else if (props.function || props.color_present) {
 497                 char tmp_buf[LED_MAX_NAME_SIZE];
 498
 499                 if (props.func_enum_present) {
 500                         snprintf(tmp_buf, LED_MAX_NAME_SIZE, "%s:%s-%d",
 501                                  props.color_present ? led_colors[props.color] : "",
 502                                  props.function ?: "", props.func_enum);
 503                 } else {
 504                         snprintf(tmp_buf, LED_MAX_NAME_SIZE, "%s:%s",
 505                                  props.color_present ? led_colors[props.color] : "",
 506                                  props.function ?: "");
 507                 }
 508                 if (init_data->devname_mandatory) {
 509                         snprintf(led_classdev_name, LED_MAX_NAME_SIZE, "%s:%s",
 510                                  devicename, tmp_buf);
 511                 } else {
 512                         strscpy(led_classdev_name, tmp_buf, LED_MAX_NAME_SIZE);
 513
 514                 }
 515         } else if (init_data->default_label) {
 516                 if (!devicename) {
 517                         dev_err(dev, "Legacy LED naming requires devicename segment");
 518                         return -EINVAL;
 519                 }
 520                 snprintf(led_classdev_name, LED_MAX_NAME_SIZE, "%s:%s",
 521                          devicename, init_data->default_label);
 522         } else if (is_of_node(fwnode)) {
 523                 strscpy(led_classdev_name, to_of_node(fwnode)->name,
 524                         LED_MAX_NAME_SIZE);
 525         } else
 526                 return -EINVAL;
 527
 528         return 0;
 529 }
 530 EXPORT_SYMBOL_GPL(led_compose_name);
 531
 532 enum led_default_state led_init_default_state_get(struct fwnode_handle *fwnode)
 533 {
 534         const char *state = NULL;
 535
 536         if (!fwnode_property_read_string(fwnode, "default-state", &state)) {
 537                 if (!strcmp(state, "keep"))
 538                         return LEDS_DEFSTATE_KEEP;
 539                 if (!strcmp(state, "on"))
 540                         return LEDS_DEFSTATE_ON;
 541         }
 542
 543         return LEDS_DEFSTATE_OFF;
 544 }
 545 EXPORT_SYMBOL_GPL(led_init_default_state_get);