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
 157 static void led_set_software_blink(struct led_classdev *led_cdev,
 158                                    unsigned long delay_on,
 159                                    unsigned long delay_off)
 160 {
 161         int current_brightness;
 162
 163         current_brightness = led_get_brightness(led_cdev);
 164         if (current_brightness)
 165                 led_cdev->blink_brightness = current_brightness;
 166         if (!led_cdev->blink_brightness)
 167                 led_cdev->blink_brightness = led_cdev->max_brightness;
 168
 169         led_cdev->blink_delay_on = delay_on;
 170         led_cdev->blink_delay_off = delay_off;
 171
 172         /* never on - just set to off */
 173         if (!delay_on) {
 174                 led_set_brightness_nosleep(led_cdev, LED_OFF);
 175                 return;
 176         }
 177
 178         /* never off - just set to brightness */
 179         if (!delay_off) {
 180                 led_set_brightness_nosleep(led_cdev,
 181                                            led_cdev->blink_brightness);
 182                 return;
 183         }
 184
 185         set_bit(LED_BLINK_SW, &led_cdev->work_flags);
 186         mod_timer(&led_cdev->blink_timer, jiffies + 1);
 187 }
 188
 189
 190 static void led_blink_setup(struct led_classdev *led_cdev,
 191                      unsigned long *delay_on,
 192                      unsigned long *delay_off)
 193 {
 194         if (!test_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags) &&
 195             led_cdev->blink_set &&
 196             !led_cdev->blink_set(led_cdev, delay_on, delay_off))
 197                 return;
 198
 199         /* blink with 1 Hz as default if nothing specified */
 200         if (!*delay_on && !*delay_off)
 201                 *delay_on = *delay_off = 500;
 202
 203         led_set_software_blink(led_cdev, *delay_on, *delay_off);
 204 }
 205
 206 void led_init_core(struct led_classdev *led_cdev)
 207 {
 208         INIT_WORK(&led_cdev->set_brightness_work, set_brightness_delayed);
 209
 210         timer_setup(&led_cdev->blink_timer, led_timer_function, 0);
 211 }
 212 EXPORT_SYMBOL_GPL(led_init_core);
 213
 214 void led_blink_set(struct led_classdev *led_cdev,
 215                    unsigned long *delay_on,
 216                    unsigned long *delay_off)
 217 {
 218         del_timer_sync(&led_cdev->blink_timer);
 219
 220         clear_bit(LED_BLINK_SW, &led_cdev->work_flags);
 221         clear_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags);
 222         clear_bit(LED_BLINK_ONESHOT_STOP, &led_cdev->work_flags);
 223
 224         led_blink_setup(led_cdev, delay_on, delay_off);
 225 }
 226 EXPORT_SYMBOL_GPL(led_blink_set);
 227
 228 void led_blink_set_oneshot(struct led_classdev *led_cdev,
 229                            unsigned long *delay_on,
 230                            unsigned long *delay_off,
 231                            int invert)
 232 {
 233         if (test_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags) &&
 234              timer_pending(&led_cdev->blink_timer))
 235                 return;
 236
 237         set_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags);
 238         clear_bit(LED_BLINK_ONESHOT_STOP, &led_cdev->work_flags);
 239
 240         if (invert)
 241                 set_bit(LED_BLINK_INVERT, &led_cdev->work_flags);
 242         else
 243                 clear_bit(LED_BLINK_INVERT, &led_cdev->work_flags);
 244
 245         led_blink_setup(led_cdev, delay_on, delay_off);
 246 }
 247 EXPORT_SYMBOL_GPL(led_blink_set_oneshot);
 248
 249 void led_stop_software_blink(struct led_classdev *led_cdev)
 250 {
 251         del_timer_sync(&led_cdev->blink_timer);
 252         led_cdev->blink_delay_on = 0;
 253         led_cdev->blink_delay_off = 0;
 254         clear_bit(LED_BLINK_SW, &led_cdev->work_flags);
 255 }
 256 EXPORT_SYMBOL_GPL(led_stop_software_blink);
 257
 258 void led_set_brightness(struct led_classdev *led_cdev, unsigned int brightness)
 259 {
 260         /*
 261          * If software blink is active, delay brightness setting
 262          * until the next timer tick.
 263          */
 264         if (test_bit(LED_BLINK_SW, &led_cdev->work_flags)) {
 265                 /*
 266                  * If we need to disable soft blinking delegate this to the
 267                  * work queue task to avoid problems in case we are called
 268                  * from hard irq context.
 269                  */
 270                 if (!brightness) {
 271                         set_bit(LED_BLINK_DISABLE, &led_cdev->work_flags);
 272                         schedule_work(&led_cdev->set_brightness_work);
 273                 } else {
 274                         set_bit(LED_BLINK_BRIGHTNESS_CHANGE,
 275                                 &led_cdev->work_flags);
 276                         led_cdev->new_blink_brightness = brightness;
 277                 }
 278                 return;
 279         }
 280
 281         led_set_brightness_nosleep(led_cdev, brightness);
 282 }
 283 EXPORT_SYMBOL_GPL(led_set_brightness);
 284
 285 void led_set_brightness_nopm(struct led_classdev *led_cdev, unsigned int value)
 286 {
 287         /* Use brightness_set op if available, it is guaranteed not to sleep */
 288         if (!__led_set_brightness(led_cdev, value))
 289                 return;
 290
 291         /*
 292          * Brightness setting can sleep, delegate it to a work queue task.
 293          * value 0 / LED_OFF is special, since it also disables hw-blinking
 294          * (sw-blink disable is handled in led_set_brightness()).
 295          * To avoid a hw-blink-disable getting lost when a second brightness
 296          * change is done immediately afterwards (before the work runs),
 297          * it uses a separate work_flag.
 298          */
 299         if (value) {
 300                 led_cdev->delayed_set_value = value;
 301                 set_bit(LED_SET_BRIGHTNESS, &led_cdev->work_flags);
 302         } else {
 303                 clear_bit(LED_SET_BRIGHTNESS, &led_cdev->work_flags);
 304                 set_bit(LED_SET_BRIGHTNESS_OFF, &led_cdev->work_flags);
 305         }
 306
 307         schedule_work(&led_cdev->set_brightness_work);
 308 }
 309 EXPORT_SYMBOL_GPL(led_set_brightness_nopm);
 310
 311 void led_set_brightness_nosleep(struct led_classdev *led_cdev, unsigned int value)
 312 {
 313         led_cdev->brightness = min(value, led_cdev->max_brightness);
 314
 315         if (led_cdev->flags & LED_SUSPENDED)
 316                 return;
 317
 318         led_set_brightness_nopm(led_cdev, led_cdev->brightness);
 319 }
 320 EXPORT_SYMBOL_GPL(led_set_brightness_nosleep);
 321
 322 int led_set_brightness_sync(struct led_classdev *led_cdev, unsigned int value)
 323 {
 324         if (led_cdev->blink_delay_on || led_cdev->blink_delay_off)
 325                 return -EBUSY;
 326
 327         led_cdev->brightness = min(value, led_cdev->max_brightness);
 328
 329         if (led_cdev->flags & LED_SUSPENDED)
 330                 return 0;
 331
 332         return __led_set_brightness_blocking(led_cdev, led_cdev->brightness);
 333 }
 334 EXPORT_SYMBOL_GPL(led_set_brightness_sync);
 335
 336 int led_update_brightness(struct led_classdev *led_cdev)
 337 {
 338         int ret = 0;
 339
 340         if (led_cdev->brightness_get) {
 341                 ret = led_cdev->brightness_get(led_cdev);
 342                 if (ret >= 0) {
 343                         led_cdev->brightness = ret;
 344                         return 0;
 345                 }
 346         }
 347
 348         return ret;
 349 }
 350 EXPORT_SYMBOL_GPL(led_update_brightness);
 351
 352 u32 *led_get_default_pattern(struct led_classdev *led_cdev, unsigned int *size)
 353 {
 354         struct fwnode_handle *fwnode = led_cdev->dev->fwnode;
 355         u32 *pattern;
 356         int count;
 357
 358         count = fwnode_property_count_u32(fwnode, "led-pattern");
 359         if (count < 0)
 360                 return NULL;
 361
 362         pattern = kcalloc(count, sizeof(*pattern), GFP_KERNEL);
 363         if (!pattern)
 364                 return NULL;
 365
 366         if (fwnode_property_read_u32_array(fwnode, "led-pattern", pattern, count)) {
 367                 kfree(pattern);
 368                 return NULL;
 369         }
 370
 371         *size = count;
 372
 373         return pattern;
 374 }
 375 EXPORT_SYMBOL_GPL(led_get_default_pattern);
 376
 377 /* Caller must ensure led_cdev->led_access held */
 378 void led_sysfs_disable(struct led_classdev *led_cdev)
 379 {
 380         lockdep_assert_held(&led_cdev->led_access);
 381
 382         led_cdev->flags |= LED_SYSFS_DISABLE;
 383 }
 384 EXPORT_SYMBOL_GPL(led_sysfs_disable);
 385
 386 /* Caller must ensure led_cdev->led_access held */
 387 void led_sysfs_enable(struct led_classdev *led_cdev)
 388 {
 389         lockdep_assert_held(&led_cdev->led_access);
 390
 391         led_cdev->flags &= ~LED_SYSFS_DISABLE;
 392 }
 393 EXPORT_SYMBOL_GPL(led_sysfs_enable);
 394
 395 static void led_parse_fwnode_props(struct device *dev,
 396                                    struct fwnode_handle *fwnode,
 397                                    struct led_properties *props)
 398 {
 399         int ret;
 400
 401         if (!fwnode)
 402                 return;
 403
 404         if (fwnode_property_present(fwnode, "label")) {
 405                 ret = fwnode_property_read_string(fwnode, "label", &props->label);
 406                 if (ret)
 407                         dev_err(dev, "Error parsing 'label' property (%d)\n", ret);
 408                 return;
 409         }
 410
 411         if (fwnode_property_present(fwnode, "color")) {
 412                 ret = fwnode_property_read_u32(fwnode, "color", &props->color);
 413                 if (ret)
 414                         dev_err(dev, "Error parsing 'color' property (%d)\n", ret);
 415                 else if (props->color >= LED_COLOR_ID_MAX)
 416                         dev_err(dev, "LED color identifier out of range\n");
 417                 else
 418                         props->color_present = true;
 419         }
 420
 421
 422         if (!fwnode_property_present(fwnode, "function"))
 423                 return;
 424
 425         ret = fwnode_property_read_string(fwnode, "function", &props->function);
 426         if (ret) {
 427                 dev_err(dev,
 428                         "Error parsing 'function' property (%d)\n",
 429                         ret);
 430         }
 431
 432         if (!fwnode_property_present(fwnode, "function-enumerator"))
 433                 return;
 434
 435         ret = fwnode_property_read_u32(fwnode, "function-enumerator",
 436                                        &props->func_enum);
 437         if (ret) {
 438                 dev_err(dev,
 439                         "Error parsing 'function-enumerator' property (%d)\n",
 440                         ret);
 441         } else {
 442                 props->func_enum_present = true;
 443         }
 444 }
 445
 446 int led_compose_name(struct device *dev, struct led_init_data *init_data,
 447                      char *led_classdev_name)
 448 {
 449         struct led_properties props = {};
 450         struct fwnode_handle *fwnode = init_data->fwnode;
 451         const char *devicename = init_data->devicename;
 452
 453         /* We want to label LEDs that can produce full range of colors
 454          * as RGB, not multicolor */
 455         BUG_ON(props.color == LED_COLOR_ID_MULTI);
 456
 457         if (!led_classdev_name)
 458                 return -EINVAL;
 459
 460         led_parse_fwnode_props(dev, fwnode, &props);
 461
 462         if (props.label) {
 463                 /*
 464                  * If init_data.devicename is NULL, then it indicates that
 465                  * DT label should be used as-is for LED class device name.
 466                  * Otherwise the label is prepended with devicename to compose
 467                  * the final LED class device name.
 468                  */
 469                 if (!devicename) {
 470                         strscpy(led_classdev_name, props.label,
 471                                 LED_MAX_NAME_SIZE);
 472                 } else {
 473                         snprintf(led_classdev_name, LED_MAX_NAME_SIZE, "%s:%s",
 474                                  devicename, props.label);
 475                 }
 476         } else if (props.function || props.color_present) {
 477                 char tmp_buf[LED_MAX_NAME_SIZE];
 478
 479                 if (props.func_enum_present) {
 480                         snprintf(tmp_buf, LED_MAX_NAME_SIZE, "%s:%s-%d",
 481                                  props.color_present ? led_colors[props.color] : "",
 482                                  props.function ?: "", props.func_enum);
 483                 } else {
 484                         snprintf(tmp_buf, LED_MAX_NAME_SIZE, "%s:%s",
 485                                  props.color_present ? led_colors[props.color] : "",
 486                                  props.function ?: "");
 487                 }
 488                 if (init_data->devname_mandatory) {
 489                         snprintf(led_classdev_name, LED_MAX_NAME_SIZE, "%s:%s",
 490                                  devicename, tmp_buf);
 491                 } else {
 492                         strscpy(led_classdev_name, tmp_buf, LED_MAX_NAME_SIZE);
 493
 494                 }
 495         } else if (init_data->default_label) {
 496                 if (!devicename) {
 497                         dev_err(dev, "Legacy LED naming requires devicename segment");
 498                         return -EINVAL;
 499                 }
 500                 snprintf(led_classdev_name, LED_MAX_NAME_SIZE, "%s:%s",
 501                          devicename, init_data->default_label);
 502         } else if (is_of_node(fwnode)) {
 503                 strscpy(led_classdev_name, to_of_node(fwnode)->name,
 504                         LED_MAX_NAME_SIZE);
 505         } else
 506                 return -EINVAL;
 507
 508         return 0;
 509 }
 510 EXPORT_SYMBOL_GPL(led_compose_name);
 511
 512 enum led_default_state led_init_default_state_get(struct fwnode_handle *fwnode)
 513 {
 514         const char *state = NULL;
 515
 516         if (!fwnode_property_read_string(fwnode, "default-state", &state)) {
 517                 if (!strcmp(state, "keep"))
 518                         return LEDS_DEFSTATE_KEEP;
 519                 if (!strcmp(state, "on"))
 520                         return LEDS_DEFSTATE_ON;
 521         }
 522
 523         return LEDS_DEFSTATE_OFF;
 524 }
 525 EXPORT_SYMBOL_GPL(led_init_default_state_get);