LXR linux/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
  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,
  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
  53static 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
  62static 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
 119static 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
 142static 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
 175static 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
 191void 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}
 197EXPORT_SYMBOL_GPL(led_init_core);
 198
 199void 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}
 211EXPORT_SYMBOL_GPL(led_blink_set);
 212
 213void 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}
 232EXPORT_SYMBOL_GPL(led_blink_set_oneshot);
 233
 234void 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}
 241EXPORT_SYMBOL_GPL(led_stop_software_blink);
 242
 243void 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}
 269EXPORT_SYMBOL_GPL(led_set_brightness);
 270
 271void 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}
 282EXPORT_SYMBOL_GPL(led_set_brightness_nopm);
 283
 284void 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}
 294EXPORT_SYMBOL_GPL(led_set_brightness_nosleep);
 295
 296int 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}
 309EXPORT_SYMBOL_GPL(led_set_brightness_sync);
 310
 311int 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}
 325EXPORT_SYMBOL_GPL(led_update_brightness);
 326
 327u32 *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}
 350EXPORT_SYMBOL_GPL(led_get_default_pattern);
 351
 352/* Caller must ensure led_cdev->led_access held */
 353void 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}
 359EXPORT_SYMBOL_GPL(led_sysfs_disable);
 360
 361/* Caller must ensure led_cdev->led_access held */
 362void 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}
 368EXPORT_SYMBOL_GPL(led_sysfs_enable);
 369
 370static 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
 421int 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}
 485EXPORT_SYMBOL_GPL(led_compose_name);
 486