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