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/rwsem.h>
  17#include <linux/slab.h>
  18#include "leds.h"
  19
  20DECLARE_RWSEM(leds_list_lock);
  21EXPORT_SYMBOL_GPL(leds_list_lock);
  22
  23LIST_HEAD(leds_list);
  24EXPORT_SYMBOL_GPL(leds_list);
  25
  26static int __led_set_brightness(struct led_classdev *led_cdev,
  27                                enum led_brightness value)
  28{
  29        if (!led_cdev->brightness_set)
  30                return -ENOTSUPP;
  31
  32        led_cdev->brightness_set(led_cdev, value);
  33
  34        return 0;
  35}
  36
  37static int __led_set_brightness_blocking(struct led_classdev *led_cdev,
  38                                         enum led_brightness value)
  39{
  40        if (!led_cdev->brightness_set_blocking)
  41                return -ENOTSUPP;
  42
  43        return led_cdev->brightness_set_blocking(led_cdev, value);
  44}
  45
  46static void led_timer_function(struct timer_list *t)
  47{
  48        struct led_classdev *led_cdev = from_timer(led_cdev, t, blink_timer);
  49        unsigned long brightness;
  50        unsigned long delay;
  51
  52        if (!led_cdev->blink_delay_on || !led_cdev->blink_delay_off) {
  53                led_set_brightness_nosleep(led_cdev, LED_OFF);
  54                clear_bit(LED_BLINK_SW, &led_cdev->work_flags);
  55                return;
  56        }
  57
  58        if (test_and_clear_bit(LED_BLINK_ONESHOT_STOP,
  59                               &led_cdev->work_flags)) {
  60                clear_bit(LED_BLINK_SW, &led_cdev->work_flags);
  61                return;
  62        }
  63
  64        brightness = led_get_brightness(led_cdev);
  65        if (!brightness) {
  66                /* Time to switch the LED on. */
  67                if (test_and_clear_bit(LED_BLINK_BRIGHTNESS_CHANGE,
  68                                        &led_cdev->work_flags))
  69                        brightness = led_cdev->new_blink_brightness;
  70                else
  71                        brightness = led_cdev->blink_brightness;
  72                delay = led_cdev->blink_delay_on;
  73        } else {
  74                /* Store the current brightness value to be able
  75                 * to restore it when the delay_off period is over.
  76                 */
  77                led_cdev->blink_brightness = brightness;
  78                brightness = LED_OFF;
  79                delay = led_cdev->blink_delay_off;
  80        }
  81
  82        led_set_brightness_nosleep(led_cdev, brightness);
  83
  84        /* Return in next iteration if led is in one-shot mode and we are in
  85         * the final blink state so that the led is toggled each delay_on +
  86         * delay_off milliseconds in worst case.
  87         */
  88        if (test_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags)) {
  89                if (test_bit(LED_BLINK_INVERT, &led_cdev->work_flags)) {
  90                        if (brightness)
  91                                set_bit(LED_BLINK_ONESHOT_STOP,
  92                                        &led_cdev->work_flags);
  93                } else {
  94                        if (!brightness)
  95                                set_bit(LED_BLINK_ONESHOT_STOP,
  96                                        &led_cdev->work_flags);
  97                }
  98        }
  99
 100        mod_timer(&led_cdev->blink_timer, jiffies + msecs_to_jiffies(delay));
 101}
 102
 103static void set_brightness_delayed(struct work_struct *ws)
 104{
 105        struct led_classdev *led_cdev =
 106                container_of(ws, struct led_classdev, set_brightness_work);
 107        int ret = 0;
 108
 109        if (test_and_clear_bit(LED_BLINK_DISABLE, &led_cdev->work_flags)) {
 110                led_cdev->delayed_set_value = LED_OFF;
 111                led_stop_software_blink(led_cdev);
 112        }
 113
 114        ret = __led_set_brightness(led_cdev, led_cdev->delayed_set_value);
 115        if (ret == -ENOTSUPP)
 116                ret = __led_set_brightness_blocking(led_cdev,
 117                                        led_cdev->delayed_set_value);
 118        if (ret < 0 &&
 119            /* LED HW might have been unplugged, therefore don't warn */
 120            !(ret == -ENODEV && (led_cdev->flags & LED_UNREGISTERING) &&
 121            (led_cdev->flags & LED_HW_PLUGGABLE)))
 122                dev_err(led_cdev->dev,
 123                        "Setting an LED's brightness failed (%d)\n", ret);
 124}
 125
 126static void led_set_software_blink(struct led_classdev *led_cdev,
 127                                   unsigned long delay_on,
 128                                   unsigned long delay_off)
 129{
 130        int current_brightness;
 131
 132        current_brightness = led_get_brightness(led_cdev);
 133        if (current_brightness)
 134                led_cdev->blink_brightness = current_brightness;
 135        if (!led_cdev->blink_brightness)
 136                led_cdev->blink_brightness = led_cdev->max_brightness;
 137
 138        led_cdev->blink_delay_on = delay_on;
 139        led_cdev->blink_delay_off = delay_off;
 140
 141        /* never on - just set to off */
 142        if (!delay_on) {
 143                led_set_brightness_nosleep(led_cdev, LED_OFF);
 144                return;
 145        }
 146
 147        /* never off - just set to brightness */
 148        if (!delay_off) {
 149                led_set_brightness_nosleep(led_cdev,
 150                                           led_cdev->blink_brightness);
 151                return;
 152        }
 153
 154        set_bit(LED_BLINK_SW, &led_cdev->work_flags);
 155        mod_timer(&led_cdev->blink_timer, jiffies + 1);
 156}
 157
 158
 159static void led_blink_setup(struct led_classdev *led_cdev,
 160                     unsigned long *delay_on,
 161                     unsigned long *delay_off)
 162{
 163        if (!test_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags) &&
 164            led_cdev->blink_set &&
 165            !led_cdev->blink_set(led_cdev, delay_on, delay_off))
 166                return;
 167
 168        /* blink with 1 Hz as default if nothing specified */
 169        if (!*delay_on && !*delay_off)
 170                *delay_on = *delay_off = 500;
 171
 172        led_set_software_blink(led_cdev, *delay_on, *delay_off);
 173}
 174
 175void led_init_core(struct led_classdev *led_cdev)
 176{
 177        INIT_WORK(&led_cdev->set_brightness_work, set_brightness_delayed);
 178
 179        timer_setup(&led_cdev->blink_timer, led_timer_function, 0);
 180}
 181EXPORT_SYMBOL_GPL(led_init_core);
 182
 183void led_blink_set(struct led_classdev *led_cdev,
 184                   unsigned long *delay_on,
 185                   unsigned long *delay_off)
 186{
 187        del_timer_sync(&led_cdev->blink_timer);
 188
 189        clear_bit(LED_BLINK_SW, &led_cdev->work_flags);
 190        clear_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags);
 191        clear_bit(LED_BLINK_ONESHOT_STOP, &led_cdev->work_flags);
 192
 193        led_blink_setup(led_cdev, delay_on, delay_off);
 194}
 195EXPORT_SYMBOL_GPL(led_blink_set);
 196
 197void led_blink_set_oneshot(struct led_classdev *led_cdev,
 198                           unsigned long *delay_on,
 199                           unsigned long *delay_off,
 200                           int invert)
 201{
 202        if (test_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags) &&
 203             timer_pending(&led_cdev->blink_timer))
 204                return;
 205
 206        set_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags);
 207        clear_bit(LED_BLINK_ONESHOT_STOP, &led_cdev->work_flags);
 208
 209        if (invert)
 210                set_bit(LED_BLINK_INVERT, &led_cdev->work_flags);
 211        else
 212                clear_bit(LED_BLINK_INVERT, &led_cdev->work_flags);
 213
 214        led_blink_setup(led_cdev, delay_on, delay_off);
 215}
 216EXPORT_SYMBOL_GPL(led_blink_set_oneshot);
 217
 218void led_stop_software_blink(struct led_classdev *led_cdev)
 219{
 220        del_timer_sync(&led_cdev->blink_timer);
 221        led_cdev->blink_delay_on = 0;
 222        led_cdev->blink_delay_off = 0;
 223        clear_bit(LED_BLINK_SW, &led_cdev->work_flags);
 224}
 225EXPORT_SYMBOL_GPL(led_stop_software_blink);
 226
 227void led_set_brightness(struct led_classdev *led_cdev,
 228                        enum led_brightness brightness)
 229{
 230        /*
 231         * If software blink is active, delay brightness setting
 232         * until the next timer tick.
 233         */
 234        if (test_bit(LED_BLINK_SW, &led_cdev->work_flags)) {
 235                /*
 236                 * If we need to disable soft blinking delegate this to the
 237                 * work queue task to avoid problems in case we are called
 238                 * from hard irq context.
 239                 */
 240                if (brightness == LED_OFF) {
 241                        set_bit(LED_BLINK_DISABLE, &led_cdev->work_flags);
 242                        schedule_work(&led_cdev->set_brightness_work);
 243                } else {
 244                        set_bit(LED_BLINK_BRIGHTNESS_CHANGE,
 245                                &led_cdev->work_flags);
 246                        led_cdev->new_blink_brightness = brightness;
 247                }
 248                return;
 249        }
 250
 251        led_set_brightness_nosleep(led_cdev, brightness);
 252}
 253EXPORT_SYMBOL_GPL(led_set_brightness);
 254
 255void led_set_brightness_nopm(struct led_classdev *led_cdev,
 256                              enum led_brightness value)
 257{
 258        /* Use brightness_set op if available, it is guaranteed not to sleep */
 259        if (!__led_set_brightness(led_cdev, value))
 260                return;
 261
 262        /* If brightness setting can sleep, delegate it to a work queue task */
 263        led_cdev->delayed_set_value = value;
 264        schedule_work(&led_cdev->set_brightness_work);
 265}
 266EXPORT_SYMBOL_GPL(led_set_brightness_nopm);
 267
 268void led_set_brightness_nosleep(struct led_classdev *led_cdev,
 269                                enum led_brightness value)
 270{
 271        led_cdev->brightness = min(value, led_cdev->max_brightness);
 272
 273        if (led_cdev->flags & LED_SUSPENDED)
 274                return;
 275
 276        led_set_brightness_nopm(led_cdev, led_cdev->brightness);
 277}
 278EXPORT_SYMBOL_GPL(led_set_brightness_nosleep);
 279
 280int led_set_brightness_sync(struct led_classdev *led_cdev,
 281                            enum led_brightness value)
 282{
 283        if (led_cdev->blink_delay_on || led_cdev->blink_delay_off)
 284                return -EBUSY;
 285
 286        led_cdev->brightness = min(value, led_cdev->max_brightness);
 287
 288        if (led_cdev->flags & LED_SUSPENDED)
 289                return 0;
 290
 291        return __led_set_brightness_blocking(led_cdev, led_cdev->brightness);
 292}
 293EXPORT_SYMBOL_GPL(led_set_brightness_sync);
 294
 295int led_update_brightness(struct led_classdev *led_cdev)
 296{
 297        int ret = 0;
 298
 299        if (led_cdev->brightness_get) {
 300                ret = led_cdev->brightness_get(led_cdev);
 301                if (ret >= 0) {
 302                        led_cdev->brightness = ret;
 303                        return 0;
 304                }
 305        }
 306
 307        return ret;
 308}
 309EXPORT_SYMBOL_GPL(led_update_brightness);
 310
 311u32 *led_get_default_pattern(struct led_classdev *led_cdev, unsigned int *size)
 312{
 313        struct device_node *np = dev_of_node(led_cdev->dev);
 314        u32 *pattern;
 315        int count;
 316
 317        if (!np)
 318                return NULL;
 319
 320        count = of_property_count_u32_elems(np, "led-pattern");
 321        if (count < 0)
 322                return NULL;
 323
 324        pattern = kcalloc(count, sizeof(*pattern), GFP_KERNEL);
 325        if (!pattern)
 326                return NULL;
 327
 328        if (of_property_read_u32_array(np, "led-pattern", pattern, count)) {
 329                kfree(pattern);
 330                return NULL;
 331        }
 332
 333        *size = count;
 334
 335        return pattern;
 336}
 337EXPORT_SYMBOL_GPL(led_get_default_pattern);
 338
 339/* Caller must ensure led_cdev->led_access held */
 340void led_sysfs_disable(struct led_classdev *led_cdev)
 341{
 342        lockdep_assert_held(&led_cdev->led_access);
 343
 344        led_cdev->flags |= LED_SYSFS_DISABLE;
 345}
 346EXPORT_SYMBOL_GPL(led_sysfs_disable);
 347
 348/* Caller must ensure led_cdev->led_access held */
 349void led_sysfs_enable(struct led_classdev *led_cdev)
 350{
 351        lockdep_assert_held(&led_cdev->led_access);
 352
 353        led_cdev->flags &= ~LED_SYSFS_DISABLE;
 354}
 355EXPORT_SYMBOL_GPL(led_sysfs_enable);
 356