linux/drivers/leds/led-core.c
<<
>>
Prefs
   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
  22DECLARE_RWSEM(leds_list_lock);
  23EXPORT_SYMBOL_GPL(leds_list_lock);
  24
  25LIST_HEAD(leds_list);
  26EXPORT_SYMBOL_GPL(leds_list);
  27
  28const 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};
  40EXPORT_SYMBOL_GPL(led_colors);
  41
  42static 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
  52static 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
  60static 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
 117static 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
 140static 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
 173static 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
 189void 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}
 195EXPORT_SYMBOL_GPL(led_init_core);
 196
 197void 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}
 209EXPORT_SYMBOL_GPL(led_blink_set);
 210
 211void 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}
 230EXPORT_SYMBOL_GPL(led_blink_set_oneshot);
 231
 232void 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}
 239EXPORT_SYMBOL_GPL(led_stop_software_blink);
 240
 241void led_set_brightness(struct led_classdev *led_cdev, unsigned int brightness)
 242{
 243        /*
 244         * If software blink is active, delay brightness setting
 245         * until the next timer tick.
 246         */
 247        if (test_bit(LED_BLINK_SW, &led_cdev->work_flags)) {
 248                /*
 249                 * If we need to disable soft blinking delegate this to the
 250                 * work queue task to avoid problems in case we are called
 251                 * from hard irq context.
 252                 */
 253                if (!brightness) {
 254                        set_bit(LED_BLINK_DISABLE, &led_cdev->work_flags);
 255                        schedule_work(&led_cdev->set_brightness_work);
 256                } else {
 257                        set_bit(LED_BLINK_BRIGHTNESS_CHANGE,
 258                                &led_cdev->work_flags);
 259                        led_cdev->new_blink_brightness = brightness;
 260                }
 261                return;
 262        }
 263
 264        led_set_brightness_nosleep(led_cdev, brightness);
 265}
 266EXPORT_SYMBOL_GPL(led_set_brightness);
 267
 268void led_set_brightness_nopm(struct led_classdev *led_cdev, unsigned int value)
 269{
 270        /* Use brightness_set op if available, it is guaranteed not to sleep */
 271        if (!__led_set_brightness(led_cdev, value))
 272                return;
 273
 274        /* If brightness setting can sleep, delegate it to a work queue task */
 275        led_cdev->delayed_set_value = value;
 276        schedule_work(&led_cdev->set_brightness_work);
 277}
 278EXPORT_SYMBOL_GPL(led_set_brightness_nopm);
 279
 280void led_set_brightness_nosleep(struct led_classdev *led_cdev, unsigned int value)
 281{
 282        led_cdev->brightness = min(value, led_cdev->max_brightness);
 283
 284        if (led_cdev->flags & LED_SUSPENDED)
 285                return;
 286
 287        led_set_brightness_nopm(led_cdev, led_cdev->brightness);
 288}
 289EXPORT_SYMBOL_GPL(led_set_brightness_nosleep);
 290
 291int led_set_brightness_sync(struct led_classdev *led_cdev, unsigned int value)
 292{
 293        if (led_cdev->blink_delay_on || led_cdev->blink_delay_off)
 294                return -EBUSY;
 295
 296        led_cdev->brightness = min(value, led_cdev->max_brightness);
 297
 298        if (led_cdev->flags & LED_SUSPENDED)
 299                return 0;
 300
 301        return __led_set_brightness_blocking(led_cdev, led_cdev->brightness);
 302}
 303EXPORT_SYMBOL_GPL(led_set_brightness_sync);
 304
 305int led_update_brightness(struct led_classdev *led_cdev)
 306{
 307        int ret = 0;
 308
 309        if (led_cdev->brightness_get) {
 310                ret = led_cdev->brightness_get(led_cdev);
 311                if (ret >= 0) {
 312                        led_cdev->brightness = ret;
 313                        return 0;
 314                }
 315        }
 316
 317        return ret;
 318}
 319EXPORT_SYMBOL_GPL(led_update_brightness);
 320
 321u32 *led_get_default_pattern(struct led_classdev *led_cdev, unsigned int *size)
 322{
 323        struct fwnode_handle *fwnode = led_cdev->dev->fwnode;
 324        u32 *pattern;
 325        int count;
 326
 327        count = fwnode_property_count_u32(fwnode, "led-pattern");
 328        if (count < 0)
 329                return NULL;
 330
 331        pattern = kcalloc(count, sizeof(*pattern), GFP_KERNEL);
 332        if (!pattern)
 333                return NULL;
 334
 335        if (fwnode_property_read_u32_array(fwnode, "led-pattern", pattern, count)) {
 336                kfree(pattern);
 337                return NULL;
 338        }
 339
 340        *size = count;
 341
 342        return pattern;
 343}
 344EXPORT_SYMBOL_GPL(led_get_default_pattern);
 345
 346/* Caller must ensure led_cdev->led_access held */
 347void led_sysfs_disable(struct led_classdev *led_cdev)
 348{
 349        lockdep_assert_held(&led_cdev->led_access);
 350
 351        led_cdev->flags |= LED_SYSFS_DISABLE;
 352}
 353EXPORT_SYMBOL_GPL(led_sysfs_disable);
 354
 355/* Caller must ensure led_cdev->led_access held */
 356void led_sysfs_enable(struct led_classdev *led_cdev)
 357{
 358        lockdep_assert_held(&led_cdev->led_access);
 359
 360        led_cdev->flags &= ~LED_SYSFS_DISABLE;
 361}
 362EXPORT_SYMBOL_GPL(led_sysfs_enable);
 363
 364static void led_parse_fwnode_props(struct device *dev,
 365                                   struct fwnode_handle *fwnode,
 366                                   struct led_properties *props)
 367{
 368        int ret;
 369
 370        if (!fwnode)
 371                return;
 372
 373        if (fwnode_property_present(fwnode, "label")) {
 374                ret = fwnode_property_read_string(fwnode, "label", &props->label);
 375                if (ret)
 376                        dev_err(dev, "Error parsing 'label' property (%d)\n", ret);
 377                return;
 378        }
 379
 380        if (fwnode_property_present(fwnode, "color")) {
 381                ret = fwnode_property_read_u32(fwnode, "color", &props->color);
 382                if (ret)
 383                        dev_err(dev, "Error parsing 'color' property (%d)\n", ret);
 384                else if (props->color >= LED_COLOR_ID_MAX)
 385                        dev_err(dev, "LED color identifier out of range\n");
 386                else
 387                        props->color_present = true;
 388        }
 389
 390
 391        if (!fwnode_property_present(fwnode, "function"))
 392                return;
 393
 394        ret = fwnode_property_read_string(fwnode, "function", &props->function);
 395        if (ret) {
 396                dev_err(dev,
 397                        "Error parsing 'function' property (%d)\n",
 398                        ret);
 399        }
 400
 401        if (!fwnode_property_present(fwnode, "function-enumerator"))
 402                return;
 403
 404        ret = fwnode_property_read_u32(fwnode, "function-enumerator",
 405                                       &props->func_enum);
 406        if (ret) {
 407                dev_err(dev,
 408                        "Error parsing 'function-enumerator' property (%d)\n",
 409                        ret);
 410        } else {
 411                props->func_enum_present = true;
 412        }
 413}
 414
 415int led_compose_name(struct device *dev, struct led_init_data *init_data,
 416                     char *led_classdev_name)
 417{
 418        struct led_properties props = {};
 419        struct fwnode_handle *fwnode = init_data->fwnode;
 420        const char *devicename = init_data->devicename;
 421
 422        /* We want to label LEDs that can produce full range of colors
 423         * as RGB, not multicolor */
 424        BUG_ON(props.color == LED_COLOR_ID_MULTI);
 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}
 479EXPORT_SYMBOL_GPL(led_compose_name);
 480