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 };
  38 EXPORT_SYMBOL_GPL(led_colors);
  39
  40 static int __led_set_brightness(struct led_classdev *led_cdev,
  41                                 enum led_brightness value)
  42 {
  43         if (!led_cdev->brightness_set)
  44                 return -ENOTSUPP;
  45
  46         led_cdev->brightness_set(led_cdev, value);
  47
  48         return 0;
  49 }
  50
  51 static int __led_set_brightness_blocking(struct led_classdev *led_cdev,
  52                                          enum led_brightness 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(struct work_struct *ws)
 118 {
 119         struct led_classdev *led_cdev =
 120                 container_of(ws, struct led_classdev, set_brightness_work);
 121         int ret = 0;
 122
 123         if (test_and_clear_bit(LED_BLINK_DISABLE, &led_cdev->work_flags)) {
 124                 led_cdev->delayed_set_value = LED_OFF;
 125                 led_stop_software_blink(led_cdev);
 126         }
 127
 128         ret = __led_set_brightness(led_cdev, led_cdev->delayed_set_value);
 129         if (ret == -ENOTSUPP)
 130                 ret = __led_set_brightness_blocking(led_cdev,
 131                                         led_cdev->delayed_set_value);
 132         if (ret < 0 &&
 133             /* LED HW might have been unplugged, therefore don't warn */
 134             !(ret == -ENODEV && (led_cdev->flags & LED_UNREGISTERING) &&
 135             (led_cdev->flags & LED_HW_PLUGGABLE)))
 136                 dev_err(led_cdev->dev,
 137                         "Setting an LED's brightness failed (%d)\n", ret);
 138 }
 139
 140 static void led_set_software_blink(struct led_classdev *led_cdev,
 141                                    unsigned long delay_on,
 142                                    unsigned long delay_off)
 143 {
 144         int current_brightness;
 145
 146         current_brightness = led_get_brightness(led_cdev);
 147         if (current_brightness)
 148                 led_cdev->blink_brightness = current_brightness;
 149         if (!led_cdev->blink_brightness)
 150                 led_cdev->blink_brightness = led_cdev->max_brightness;
 151
 152         led_cdev->blink_delay_on = delay_on;
 153         led_cdev->blink_delay_off = delay_off;
 154
 155         /* never on - just set to off */
 156         if (!delay_on) {
 157                 led_set_brightness_nosleep(led_cdev, LED_OFF);
 158                 return;
 159         }
 160
 161         /* never off - just set to brightness */
 162         if (!delay_off) {
 163                 led_set_brightness_nosleep(led_cdev,
 164                                            led_cdev->blink_brightness);
 165                 return;
 166         }
 167
 168         set_bit(LED_BLINK_SW, &led_cdev->work_flags);
 169         mod_timer(&led_cdev->blink_timer, jiffies + 1);
 170 }
 171
 172
 173 static void led_blink_setup(struct led_classdev *led_cdev,
 174                      unsigned long *delay_on,
 175                      unsigned long *delay_off)
 176 {
 177         if (!test_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags) &&
 178             led_cdev->blink_set &&
 179             !led_cdev->blink_set(led_cdev, delay_on, delay_off))
 180                 return;
 181
 182         /* blink with 1 Hz as default if nothing specified */
 183         if (!*delay_on && !*delay_off)
 184                 *delay_on = *delay_off = 500;
 185
 186         led_set_software_blink(led_cdev, *delay_on, *delay_off);
 187 }
 188
 189 void led_init_core(struct led_classdev *led_cdev)
 190 {
 191         INIT_WORK(&led_cdev->set_brightness_work, set_brightness_delayed);
 192
 193         timer_setup(&led_cdev->blink_timer, led_timer_function, 0);
 194 }
 195 EXPORT_SYMBOL_GPL(led_init_core);
 196
 197 void led_blink_set(struct led_classdev *led_cdev,
 198                    unsigned long *delay_on,
 199                    unsigned long *delay_off)
 200 {
 201         del_timer_sync(&led_cdev->blink_timer);
 202
 203         clear_bit(LED_BLINK_SW, &led_cdev->work_flags);
 204         clear_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags);
 205         clear_bit(LED_BLINK_ONESHOT_STOP, &led_cdev->work_flags);
 206
 207         led_blink_setup(led_cdev, delay_on, delay_off);
 208 }
 209 EXPORT_SYMBOL_GPL(led_blink_set);
 210
 211 void led_blink_set_oneshot(struct led_classdev *led_cdev,
 212                            unsigned long *delay_on,
 213                            unsigned long *delay_off,
 214                            int invert)
 215 {
 216         if (test_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags) &&
 217              timer_pending(&led_cdev->blink_timer))
 218                 return;
 219
 220         set_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags);
 221         clear_bit(LED_BLINK_ONESHOT_STOP, &led_cdev->work_flags);
 222
 223         if (invert)
 224                 set_bit(LED_BLINK_INVERT, &led_cdev->work_flags);
 225         else
 226                 clear_bit(LED_BLINK_INVERT, &led_cdev->work_flags);
 227
 228         led_blink_setup(led_cdev, delay_on, delay_off);
 229 }
 230 EXPORT_SYMBOL_GPL(led_blink_set_oneshot);
 231
 232 void led_stop_software_blink(struct led_classdev *led_cdev)
 233 {
 234         del_timer_sync(&led_cdev->blink_timer);
 235         led_cdev->blink_delay_on = 0;
 236         led_cdev->blink_delay_off = 0;
 237         clear_bit(LED_BLINK_SW, &led_cdev->work_flags);
 238 }
 239 EXPORT_SYMBOL_GPL(led_stop_software_blink);
 240
 241 void led_set_brightness(struct led_classdev *led_cdev,
 242                         enum led_brightness brightness)
 243 {
 244         /*
 245          * If software blink is active, delay brightness setting
 246          * until the next timer tick.
 247          */
 248         if (test_bit(LED_BLINK_SW, &led_cdev->work_flags)) {
 249                 /*
 250                  * If we need to disable soft blinking delegate this to the
 251                  * work queue task to avoid problems in case we are called
 252                  * from hard irq context.
 253                  */
 254                 if (brightness == LED_OFF) {
 255                         set_bit(LED_BLINK_DISABLE, &led_cdev->work_flags);
 256                         schedule_work(&led_cdev->set_brightness_work);
 257                 } else {
 258                         set_bit(LED_BLINK_BRIGHTNESS_CHANGE,
 259                                 &led_cdev->work_flags);
 260                         led_cdev->new_blink_brightness = brightness;
 261                 }
 262                 return;
 263         }
 264
 265         led_set_brightness_nosleep(led_cdev, brightness);
 266 }
 267 EXPORT_SYMBOL_GPL(led_set_brightness);
 268
 269 void led_set_brightness_nopm(struct led_classdev *led_cdev,
 270                               enum led_brightness value)
 271 {
 272         /* Use brightness_set op if available, it is guaranteed not to sleep */
 273         if (!__led_set_brightness(led_cdev, value))
 274                 return;
 275
 276         /* If brightness setting can sleep, delegate it to a work queue task */
 277         led_cdev->delayed_set_value = value;
 278         schedule_work(&led_cdev->set_brightness_work);
 279 }
 280 EXPORT_SYMBOL_GPL(led_set_brightness_nopm);
 281
 282 void led_set_brightness_nosleep(struct led_classdev *led_cdev,
 283                                 enum led_brightness value)
 284 {
 285         led_cdev->brightness = min(value, led_cdev->max_brightness);
 286
 287         if (led_cdev->flags & LED_SUSPENDED)
 288                 return;
 289
 290         led_set_brightness_nopm(led_cdev, led_cdev->brightness);
 291 }
 292 EXPORT_SYMBOL_GPL(led_set_brightness_nosleep);
 293
 294 int led_set_brightness_sync(struct led_classdev *led_cdev,
 295                             enum led_brightness value)
 296 {
 297         if (led_cdev->blink_delay_on || led_cdev->blink_delay_off)
 298                 return -EBUSY;
 299
 300         led_cdev->brightness = min(value, led_cdev->max_brightness);
 301
 302         if (led_cdev->flags & LED_SUSPENDED)
 303                 return 0;
 304
 305         return __led_set_brightness_blocking(led_cdev, led_cdev->brightness);
 306 }
 307 EXPORT_SYMBOL_GPL(led_set_brightness_sync);
 308
 309 int led_update_brightness(struct led_classdev *led_cdev)
 310 {
 311         int ret = 0;
 312
 313         if (led_cdev->brightness_get) {
 314                 ret = led_cdev->brightness_get(led_cdev);
 315                 if (ret >= 0) {
 316                         led_cdev->brightness = ret;
 317                         return 0;
 318                 }
 319         }
 320
 321         return ret;
 322 }
 323 EXPORT_SYMBOL_GPL(led_update_brightness);
 324
 325 u32 *led_get_default_pattern(struct led_classdev *led_cdev, unsigned int *size)
 326 {
 327         struct fwnode_handle *fwnode = led_cdev->dev->fwnode;
 328         u32 *pattern;
 329         int count;
 330
 331         count = fwnode_property_count_u32(fwnode, "led-pattern");
 332         if (count < 0)
 333                 return NULL;
 334
 335         pattern = kcalloc(count, sizeof(*pattern), GFP_KERNEL);
 336         if (!pattern)
 337                 return NULL;
 338
 339         if (fwnode_property_read_u32_array(fwnode, "led-pattern", pattern, count)) {
 340                 kfree(pattern);
 341                 return NULL;
 342         }
 343
 344         *size = count;
 345
 346         return pattern;
 347 }
 348 EXPORT_SYMBOL_GPL(led_get_default_pattern);
 349
 350 /* Caller must ensure led_cdev->led_access held */
 351 void led_sysfs_disable(struct led_classdev *led_cdev)
 352 {
 353         lockdep_assert_held(&led_cdev->led_access);
 354
 355         led_cdev->flags |= LED_SYSFS_DISABLE;
 356 }
 357 EXPORT_SYMBOL_GPL(led_sysfs_disable);
 358
 359 /* Caller must ensure led_cdev->led_access held */
 360 void led_sysfs_enable(struct led_classdev *led_cdev)
 361 {
 362         lockdep_assert_held(&led_cdev->led_access);
 363
 364         led_cdev->flags &= ~LED_SYSFS_DISABLE;
 365 }
 366 EXPORT_SYMBOL_GPL(led_sysfs_enable);
 367
 368 static void led_parse_fwnode_props(struct device *dev,
 369                                    struct fwnode_handle *fwnode,
 370                                    struct led_properties *props)
 371 {
 372         int ret;
 373
 374         if (!fwnode)
 375                 return;
 376
 377         if (fwnode_property_present(fwnode, "label")) {
 378                 ret = fwnode_property_read_string(fwnode, "label", &props->label);
 379                 if (ret)
 380                         dev_err(dev, "Error parsing 'label' property (%d)\n", ret);
 381                 return;
 382         }
 383
 384         if (fwnode_property_present(fwnode, "color")) {
 385                 ret = fwnode_property_read_u32(fwnode, "color", &props->color);
 386                 if (ret)
 387                         dev_err(dev, "Error parsing 'color' property (%d)\n", ret);
 388                 else if (props->color >= LED_COLOR_ID_MAX)
 389                         dev_err(dev, "LED color identifier out of range\n");
 390                 else
 391                         props->color_present = true;
 392         }
 393
 394
 395         if (!fwnode_property_present(fwnode, "function"))
 396                 return;
 397
 398         ret = fwnode_property_read_string(fwnode, "function", &props->function);
 399         if (ret) {
 400                 dev_err(dev,
 401                         "Error parsing 'function' property (%d)\n",
 402                         ret);
 403         }
 404
 405         if (!fwnode_property_present(fwnode, "function-enumerator"))
 406                 return;
 407
 408         ret = fwnode_property_read_u32(fwnode, "function-enumerator",
 409                                        &props->func_enum);
 410         if (ret) {
 411                 dev_err(dev,
 412                         "Error parsing 'function-enumerator' property (%d)\n",
 413                         ret);
 414         } else {
 415                 props->func_enum_present = true;
 416         }
 417 }
 418
 419 int led_compose_name(struct device *dev, struct led_init_data *init_data,
 420                      char *led_classdev_name)
 421 {
 422         struct led_properties props = {};
 423         struct fwnode_handle *fwnode = init_data->fwnode;
 424         const char *devicename = init_data->devicename;
 425
 426         if (!led_classdev_name)
 427                 return -EINVAL;
 428
 429         led_parse_fwnode_props(dev, fwnode, &props);
 430
 431         if (props.label) {
 432                 /*
 433                  * If init_data.devicename is NULL, then it indicates that
 434                  * DT label should be used as-is for LED class device name.
 435                  * Otherwise the label is prepended with devicename to compose
 436                  * the final LED class device name.
 437                  */
 438                 if (!devicename) {
 439                         strscpy(led_classdev_name, props.label,
 440                                 LED_MAX_NAME_SIZE);
 441                 } else {
 442                         snprintf(led_classdev_name, LED_MAX_NAME_SIZE, "%s:%s",
 443                                  devicename, props.label);
 444                 }
 445         } else if (props.function || props.color_present) {
 446                 char tmp_buf[LED_MAX_NAME_SIZE];
 447
 448                 if (props.func_enum_present) {
 449                         snprintf(tmp_buf, LED_MAX_NAME_SIZE, "%s:%s-%d",
 450                                  props.color_present ? led_colors[props.color] : "",
 451                                  props.function ?: "", props.func_enum);
 452                 } else {
 453                         snprintf(tmp_buf, LED_MAX_NAME_SIZE, "%s:%s",
 454                                  props.color_present ? led_colors[props.color] : "",
 455                                  props.function ?: "");
 456                 }
 457                 if (init_data->devname_mandatory) {
 458                         snprintf(led_classdev_name, LED_MAX_NAME_SIZE, "%s:%s",
 459                                  devicename, tmp_buf);
 460                 } else {
 461                         strscpy(led_classdev_name, tmp_buf, LED_MAX_NAME_SIZE);
 462
 463                 }
 464         } else if (init_data->default_label) {
 465                 if (!devicename) {
 466                         dev_err(dev, "Legacy LED naming requires devicename segment");
 467                         return -EINVAL;
 468                 }
 469                 snprintf(led_classdev_name, LED_MAX_NAME_SIZE, "%s:%s",
 470                          devicename, init_data->default_label);
 471         } else if (is_of_node(fwnode)) {
 472                 strscpy(led_classdev_name, to_of_node(fwnode)->name,
 473                         LED_MAX_NAME_SIZE);
 474         } else
 475                 return -EINVAL;
 476
 477         return 0;
 478 }
 479 EXPORT_SYMBOL_GPL(led_compose_name);