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         [LED_COLOR_ID_PURPLE] = "purple",
  40         [LED_COLOR_ID_ORANGE] = "orange",
  41         [LED_COLOR_ID_PINK] = "pink",
  42         [LED_COLOR_ID_CYAN] = "cyan",
  43         [LED_COLOR_ID_LIME] = "lime",
  44 };
  45 EXPORT_SYMBOL_GPL(led_colors);
  46
  47 static int __led_set_brightness(struct led_classdev *led_cdev, unsigned int value)
  48 {
  49         if (!led_cdev->brightness_set)
  50                 return -ENOTSUPP;
  51
  52         led_cdev->brightness_set(led_cdev, value);
  53
  54         return 0;
  55 }
  56
  57 static int __led_set_brightness_blocking(struct led_classdev *led_cdev, unsigned int value)
  58 {
  59         if (!led_cdev->brightness_set_blocking)
  60                 return -ENOTSUPP;
  61
  62         return led_cdev->brightness_set_blocking(led_cdev, value);
  63 }
  64
  65 static void led_timer_function(struct timer_list *t)
  66 {
  67         struct led_classdev *led_cdev = from_timer(led_cdev, t, blink_timer);
  68         unsigned long brightness;
  69         unsigned long delay;
  70
  71         if (!led_cdev->blink_delay_on || !led_cdev->blink_delay_off) {
  72                 led_set_brightness_nosleep(led_cdev, LED_OFF);
  73                 clear_bit(LED_BLINK_SW, &led_cdev->work_flags);
  74                 return;
  75         }
  76
  77         if (test_and_clear_bit(LED_BLINK_ONESHOT_STOP,
  78                                &led_cdev->work_flags)) {
  79                 clear_bit(LED_BLINK_SW, &led_cdev->work_flags);
  80                 return;
  81         }
  82
  83         brightness = led_get_brightness(led_cdev);
  84         if (!brightness) {
  85                 /* Time to switch the LED on. */
  86                 if (test_and_clear_bit(LED_BLINK_BRIGHTNESS_CHANGE,
  87                                         &led_cdev->work_flags))
  88                         brightness = led_cdev->new_blink_brightness;
  89                 else
  90                         brightness = led_cdev->blink_brightness;
  91                 delay = led_cdev->blink_delay_on;
  92         } else {
  93                 /* Store the current brightness value to be able
  94                  * to restore it when the delay_off period is over.
  95                  */
  96                 led_cdev->blink_brightness = brightness;
  97                 brightness = LED_OFF;
  98                 delay = led_cdev->blink_delay_off;
  99         }
 100
 101         led_set_brightness_nosleep(led_cdev, brightness);
 102
 103         /* Return in next iteration if led is in one-shot mode and we are in
 104          * the final blink state so that the led is toggled each delay_on +
 105          * delay_off milliseconds in worst case.
 106          */
 107         if (test_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags)) {
 108                 if (test_bit(LED_BLINK_INVERT, &led_cdev->work_flags)) {
 109                         if (brightness)
 110                                 set_bit(LED_BLINK_ONESHOT_STOP,
 111                                         &led_cdev->work_flags);
 112                 } else {
 113                         if (!brightness)
 114                                 set_bit(LED_BLINK_ONESHOT_STOP,
 115                                         &led_cdev->work_flags);
 116                 }
 117         }
 118
 119         mod_timer(&led_cdev->blink_timer, jiffies + msecs_to_jiffies(delay));
 120 }
 121
 122 static void set_brightness_delayed_set_brightness(struct led_classdev *led_cdev,
 123                                                   unsigned int value)
 124 {
 125         int ret = 0;
 126
 127         ret = __led_set_brightness(led_cdev, value);
 128         if (ret == -ENOTSUPP)
 129                 ret = __led_set_brightness_blocking(led_cdev, value);
 130         if (ret < 0 &&
 131             /* LED HW might have been unplugged, therefore don't warn */
 132             !(ret == -ENODEV && (led_cdev->flags & LED_UNREGISTERING) &&
 133             (led_cdev->flags & LED_HW_PLUGGABLE)))
 134                 dev_err(led_cdev->dev,
 135                         "Setting an LED's brightness failed (%d)\n", ret);
 136 }
 137
 138 static void set_brightness_delayed(struct work_struct *ws)
 139 {
 140         struct led_classdev *led_cdev =
 141                 container_of(ws, struct led_classdev, set_brightness_work);
 142
 143         if (test_and_clear_bit(LED_BLINK_DISABLE, &led_cdev->work_flags)) {
 144                 led_stop_software_blink(led_cdev);
 145                 set_bit(LED_SET_BRIGHTNESS_OFF, &led_cdev->work_flags);
 146         }
 147
 148         /*
 149          * Triggers may call led_set_brightness(LED_OFF),
 150          * led_set_brightness(LED_FULL) in quick succession to disable blinking
 151          * and turn the LED on. Both actions may have been scheduled to run
 152          * before this work item runs once. To make sure this works properly
 153          * handle LED_SET_BRIGHTNESS_OFF first.
 154          */
 155         if (test_and_clear_bit(LED_SET_BRIGHTNESS_OFF, &led_cdev->work_flags))
 156                 set_brightness_delayed_set_brightness(led_cdev, LED_OFF);
 157
 158         if (test_and_clear_bit(LED_SET_BRIGHTNESS, &led_cdev->work_flags))
 159                 set_brightness_delayed_set_brightness(led_cdev, led_cdev->delayed_set_value);
 160
 161         if (test_and_clear_bit(LED_SET_BLINK, &led_cdev->work_flags)) {
 162                 unsigned long delay_on = led_cdev->delayed_delay_on;
 163                 unsigned long delay_off = led_cdev->delayed_delay_off;
 164
 165                 led_blink_set(led_cdev, &delay_on, &delay_off);
 166         }
 167 }
 168
 169 static void led_set_software_blink(struct led_classdev *led_cdev,
 170                                    unsigned long delay_on,
 171                                    unsigned long delay_off)
 172 {
 173         int current_brightness;
 174
 175         current_brightness = led_get_brightness(led_cdev);
 176         if (current_brightness)
 177                 led_cdev->blink_brightness = current_brightness;
 178         if (!led_cdev->blink_brightness)
 179                 led_cdev->blink_brightness = led_cdev->max_brightness;
 180
 181         led_cdev->blink_delay_on = delay_on;
 182         led_cdev->blink_delay_off = delay_off;
 183
 184         /* never on - just set to off */
 185         if (!delay_on) {
 186                 led_set_brightness_nosleep(led_cdev, LED_OFF);
 187                 return;
 188         }
 189
 190         /* never off - just set to brightness */
 191         if (!delay_off) {
 192                 led_set_brightness_nosleep(led_cdev,
 193                                            led_cdev->blink_brightness);
 194                 return;
 195         }
 196
 197         set_bit(LED_BLINK_SW, &led_cdev->work_flags);
 198         mod_timer(&led_cdev->blink_timer, jiffies + 1);
 199 }
 200
 201
 202 static void led_blink_setup(struct led_classdev *led_cdev,
 203                      unsigned long *delay_on,
 204                      unsigned long *delay_off)
 205 {
 206         if (!test_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags) &&
 207             led_cdev->blink_set &&
 208             !led_cdev->blink_set(led_cdev, delay_on, delay_off))
 209                 return;
 210
 211         /* blink with 1 Hz as default if nothing specified */
 212         if (!*delay_on && !*delay_off)
 213                 *delay_on = *delay_off = 500;
 214
 215         led_set_software_blink(led_cdev, *delay_on, *delay_off);
 216 }
 217
 218 void led_init_core(struct led_classdev *led_cdev)
 219 {
 220         INIT_WORK(&led_cdev->set_brightness_work, set_brightness_delayed);
 221
 222         timer_setup(&led_cdev->blink_timer, led_timer_function, 0);
 223 }
 224 EXPORT_SYMBOL_GPL(led_init_core);
 225
 226 void led_blink_set(struct led_classdev *led_cdev,
 227                    unsigned long *delay_on,
 228                    unsigned long *delay_off)
 229 {
 230         del_timer_sync(&led_cdev->blink_timer);
 231
 232         clear_bit(LED_BLINK_SW, &led_cdev->work_flags);
 233         clear_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags);
 234         clear_bit(LED_BLINK_ONESHOT_STOP, &led_cdev->work_flags);
 235
 236         led_blink_setup(led_cdev, delay_on, delay_off);
 237 }
 238 EXPORT_SYMBOL_GPL(led_blink_set);
 239
 240 void led_blink_set_oneshot(struct led_classdev *led_cdev,
 241                            unsigned long *delay_on,
 242                            unsigned long *delay_off,
 243                            int invert)
 244 {
 245         if (test_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags) &&
 246              timer_pending(&led_cdev->blink_timer))
 247                 return;
 248
 249         set_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags);
 250         clear_bit(LED_BLINK_ONESHOT_STOP, &led_cdev->work_flags);
 251
 252         if (invert)
 253                 set_bit(LED_BLINK_INVERT, &led_cdev->work_flags);
 254         else
 255                 clear_bit(LED_BLINK_INVERT, &led_cdev->work_flags);
 256
 257         led_blink_setup(led_cdev, delay_on, delay_off);
 258 }
 259 EXPORT_SYMBOL_GPL(led_blink_set_oneshot);
 260
 261 void led_blink_set_nosleep(struct led_classdev *led_cdev, unsigned long delay_on,
 262                            unsigned long delay_off)
 263 {
 264         /* If necessary delegate to a work queue task. */
 265         if (led_cdev->blink_set && led_cdev->brightness_set_blocking) {
 266                 led_cdev->delayed_delay_on = delay_on;
 267                 led_cdev->delayed_delay_off = delay_off;
 268                 set_bit(LED_SET_BLINK, &led_cdev->work_flags);
 269                 schedule_work(&led_cdev->set_brightness_work);
 270                 return;
 271         }
 272
 273         led_blink_set(led_cdev, &delay_on, &delay_off);
 274 }
 275 EXPORT_SYMBOL_GPL(led_blink_set_nosleep);
 276
 277 void led_stop_software_blink(struct led_classdev *led_cdev)
 278 {
 279         del_timer_sync(&led_cdev->blink_timer);
 280         led_cdev->blink_delay_on = 0;
 281         led_cdev->blink_delay_off = 0;
 282         clear_bit(LED_BLINK_SW, &led_cdev->work_flags);
 283 }
 284 EXPORT_SYMBOL_GPL(led_stop_software_blink);
 285
 286 void led_set_brightness(struct led_classdev *led_cdev, unsigned int brightness)
 287 {
 288         /*
 289          * If software blink is active, delay brightness setting
 290          * until the next timer tick.
 291          */
 292         if (test_bit(LED_BLINK_SW, &led_cdev->work_flags)) {
 293                 /*
 294                  * If we need to disable soft blinking delegate this to the
 295                  * work queue task to avoid problems in case we are called
 296                  * from hard irq context.
 297                  */
 298                 if (!brightness) {
 299                         set_bit(LED_BLINK_DISABLE, &led_cdev->work_flags);
 300                         schedule_work(&led_cdev->set_brightness_work);
 301                 } else {
 302                         set_bit(LED_BLINK_BRIGHTNESS_CHANGE,
 303                                 &led_cdev->work_flags);
 304                         led_cdev->new_blink_brightness = brightness;
 305                 }
 306                 return;
 307         }
 308
 309         led_set_brightness_nosleep(led_cdev, brightness);
 310 }
 311 EXPORT_SYMBOL_GPL(led_set_brightness);
 312
 313 void led_set_brightness_nopm(struct led_classdev *led_cdev, unsigned int value)
 314 {
 315         /* Use brightness_set op if available, it is guaranteed not to sleep */
 316         if (!__led_set_brightness(led_cdev, value))
 317                 return;
 318
 319         /*
 320          * Brightness setting can sleep, delegate it to a work queue task.
 321          * value 0 / LED_OFF is special, since it also disables hw-blinking
 322          * (sw-blink disable is handled in led_set_brightness()).
 323          * To avoid a hw-blink-disable getting lost when a second brightness
 324          * change is done immediately afterwards (before the work runs),
 325          * it uses a separate work_flag.
 326          */
 327         if (value) {
 328                 led_cdev->delayed_set_value = value;
 329                 set_bit(LED_SET_BRIGHTNESS, &led_cdev->work_flags);
 330         } else {
 331                 clear_bit(LED_SET_BRIGHTNESS, &led_cdev->work_flags);
 332                 clear_bit(LED_SET_BLINK, &led_cdev->work_flags);
 333                 set_bit(LED_SET_BRIGHTNESS_OFF, &led_cdev->work_flags);
 334         }
 335
 336         schedule_work(&led_cdev->set_brightness_work);
 337 }
 338 EXPORT_SYMBOL_GPL(led_set_brightness_nopm);
 339
 340 void led_set_brightness_nosleep(struct led_classdev *led_cdev, unsigned int value)
 341 {
 342         led_cdev->brightness = min(value, led_cdev->max_brightness);
 343
 344         if (led_cdev->flags & LED_SUSPENDED)
 345                 return;
 346
 347         led_set_brightness_nopm(led_cdev, led_cdev->brightness);
 348 }
 349 EXPORT_SYMBOL_GPL(led_set_brightness_nosleep);
 350
 351 int led_set_brightness_sync(struct led_classdev *led_cdev, unsigned int value)
 352 {
 353         if (led_cdev->blink_delay_on || led_cdev->blink_delay_off)
 354                 return -EBUSY;
 355
 356         led_cdev->brightness = min(value, led_cdev->max_brightness);
 357
 358         if (led_cdev->flags & LED_SUSPENDED)
 359                 return 0;
 360
 361         return __led_set_brightness_blocking(led_cdev, led_cdev->brightness);
 362 }
 363 EXPORT_SYMBOL_GPL(led_set_brightness_sync);
 364
 365 int led_update_brightness(struct led_classdev *led_cdev)
 366 {
 367         int ret;
 368
 369         if (led_cdev->brightness_get) {
 370                 ret = led_cdev->brightness_get(led_cdev);
 371                 if (ret < 0)
 372                         return ret;
 373
 374                 led_cdev->brightness = ret;
 375         }
 376
 377         return 0;
 378 }
 379 EXPORT_SYMBOL_GPL(led_update_brightness);
 380
 381 u32 *led_get_default_pattern(struct led_classdev *led_cdev, unsigned int *size)
 382 {
 383         struct fwnode_handle *fwnode = led_cdev->dev->fwnode;
 384         u32 *pattern;
 385         int count;
 386
 387         count = fwnode_property_count_u32(fwnode, "led-pattern");
 388         if (count < 0)
 389                 return NULL;
 390
 391         pattern = kcalloc(count, sizeof(*pattern), GFP_KERNEL);
 392         if (!pattern)
 393                 return NULL;
 394
 395         if (fwnode_property_read_u32_array(fwnode, "led-pattern", pattern, count)) {
 396                 kfree(pattern);
 397                 return NULL;
 398         }
 399
 400         *size = count;
 401
 402         return pattern;
 403 }
 404 EXPORT_SYMBOL_GPL(led_get_default_pattern);
 405
 406 /* Caller must ensure led_cdev->led_access held */
 407 void led_sysfs_disable(struct led_classdev *led_cdev)
 408 {
 409         lockdep_assert_held(&led_cdev->led_access);
 410
 411         led_cdev->flags |= LED_SYSFS_DISABLE;
 412 }
 413 EXPORT_SYMBOL_GPL(led_sysfs_disable);
 414
 415 /* Caller must ensure led_cdev->led_access held */
 416 void led_sysfs_enable(struct led_classdev *led_cdev)
 417 {
 418         lockdep_assert_held(&led_cdev->led_access);
 419
 420         led_cdev->flags &= ~LED_SYSFS_DISABLE;
 421 }
 422 EXPORT_SYMBOL_GPL(led_sysfs_enable);
 423
 424 static void led_parse_fwnode_props(struct device *dev,
 425                                    struct fwnode_handle *fwnode,
 426                                    struct led_properties *props)
 427 {
 428         int ret;
 429
 430         if (!fwnode)
 431                 return;
 432
 433         if (fwnode_property_present(fwnode, "label")) {
 434                 ret = fwnode_property_read_string(fwnode, "label", &props->label);
 435                 if (ret)
 436                         dev_err(dev, "Error parsing 'label' property (%d)\n", ret);
 437                 return;
 438         }
 439
 440         if (fwnode_property_present(fwnode, "color")) {
 441                 ret = fwnode_property_read_u32(fwnode, "color", &props->color);
 442                 if (ret)
 443                         dev_err(dev, "Error parsing 'color' property (%d)\n", ret);
 444                 else if (props->color >= LED_COLOR_ID_MAX)
 445                         dev_err(dev, "LED color identifier out of range\n");
 446                 else
 447                         props->color_present = true;
 448         }
 449
 450
 451         if (!fwnode_property_present(fwnode, "function"))
 452                 return;
 453
 454         ret = fwnode_property_read_string(fwnode, "function", &props->function);
 455         if (ret) {
 456                 dev_err(dev,
 457                         "Error parsing 'function' property (%d)\n",
 458                         ret);
 459         }
 460
 461         if (!fwnode_property_present(fwnode, "function-enumerator"))
 462                 return;
 463
 464         ret = fwnode_property_read_u32(fwnode, "function-enumerator",
 465                                        &props->func_enum);
 466         if (ret) {
 467                 dev_err(dev,
 468                         "Error parsing 'function-enumerator' property (%d)\n",
 469                         ret);
 470         } else {
 471                 props->func_enum_present = true;
 472         }
 473 }
 474
 475 int led_compose_name(struct device *dev, struct led_init_data *init_data,
 476                      char *led_classdev_name)
 477 {
 478         struct led_properties props = {};
 479         struct fwnode_handle *fwnode = init_data->fwnode;
 480         const char *devicename = init_data->devicename;
 481
 482         if (!led_classdev_name)
 483                 return -EINVAL;
 484
 485         led_parse_fwnode_props(dev, fwnode, &props);
 486
 487         if (props.label) {
 488                 /*
 489                  * If init_data.devicename is NULL, then it indicates that
 490                  * DT label should be used as-is for LED class device name.
 491                  * Otherwise the label is prepended with devicename to compose
 492                  * the final LED class device name.
 493                  */
 494                 if (!devicename) {
 495                         strscpy(led_classdev_name, props.label,
 496                                 LED_MAX_NAME_SIZE);
 497                 } else {
 498                         snprintf(led_classdev_name, LED_MAX_NAME_SIZE, "%s:%s",
 499                                  devicename, props.label);
 500                 }
 501         } else if (props.function || props.color_present) {
 502                 char tmp_buf[LED_MAX_NAME_SIZE];
 503
 504                 if (props.func_enum_present) {
 505                         snprintf(tmp_buf, LED_MAX_NAME_SIZE, "%s:%s-%d",
 506                                  props.color_present ? led_colors[props.color] : "",
 507                                  props.function ?: "", props.func_enum);
 508                 } else {
 509                         snprintf(tmp_buf, LED_MAX_NAME_SIZE, "%s:%s",
 510                                  props.color_present ? led_colors[props.color] : "",
 511                                  props.function ?: "");
 512                 }
 513                 if (init_data->devname_mandatory) {
 514                         snprintf(led_classdev_name, LED_MAX_NAME_SIZE, "%s:%s",
 515                                  devicename, tmp_buf);
 516                 } else {
 517                         strscpy(led_classdev_name, tmp_buf, LED_MAX_NAME_SIZE);
 518
 519                 }
 520         } else if (init_data->default_label) {
 521                 if (!devicename) {
 522                         dev_err(dev, "Legacy LED naming requires devicename segment");
 523                         return -EINVAL;
 524                 }
 525                 snprintf(led_classdev_name, LED_MAX_NAME_SIZE, "%s:%s",
 526                          devicename, init_data->default_label);
 527         } else if (is_of_node(fwnode)) {
 528                 strscpy(led_classdev_name, to_of_node(fwnode)->name,
 529                         LED_MAX_NAME_SIZE);
 530         } else
 531                 return -EINVAL;
 532
 533         return 0;
 534 }
 535 EXPORT_SYMBOL_GPL(led_compose_name);
 536
 537 enum led_default_state led_init_default_state_get(struct fwnode_handle *fwnode)
 538 {
 539         const char *state = NULL;
 540
 541         if (!fwnode_property_read_string(fwnode, "default-state", &state)) {
 542                 if (!strcmp(state, "keep"))
 543                         return LEDS_DEFSTATE_KEEP;
 544                 if (!strcmp(state, "on"))
 545                         return LEDS_DEFSTATE_ON;
 546         }
 547
 548         return LEDS_DEFSTATE_OFF;
 549 }
 550 EXPORT_SYMBOL_GPL(led_init_default_state_get);