drivers/leds/led-core.c

   1 /*
   2  * LED Class Core
   3  *
   4  * Copyright 2005-2006 Openedhand Ltd.
   5  *
   6  * Author: Richard Purdie <rpurdie@openedhand.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  *
  12  */
  13
  14 #include <linux/kernel.h>
  15 #include <linux/leds.h>
  16 #include <linux/list.h>
  17 #include <linux/module.h>
  18 #include <linux/mutex.h>
  19 #include <linux/rwsem.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 static void led_timer_function(unsigned long data)
  29 {
  30         struct led_classdev *led_cdev = (void *)data;
  31         unsigned long brightness;
  32         unsigned long delay;
  33
  34         if (!led_cdev->blink_delay_on || !led_cdev->blink_delay_off) {
  35                 led_set_brightness_async(led_cdev, LED_OFF);
  36                 return;
  37         }
  38
  39         if (led_cdev->flags & LED_BLINK_ONESHOT_STOP) {
  40                 led_cdev->flags &= ~LED_BLINK_ONESHOT_STOP;
  41                 return;
  42         }
  43
  44         brightness = led_get_brightness(led_cdev);
  45         if (!brightness) {
  46                 /* Time to switch the LED on. */
  47                 if (led_cdev->delayed_set_value) {
  48                         led_cdev->blink_brightness =
  49                                         led_cdev->delayed_set_value;
  50                         led_cdev->delayed_set_value = 0;
  51                 }
  52                 brightness = led_cdev->blink_brightness;
  53                 delay = led_cdev->blink_delay_on;
  54         } else {
  55                 /* Store the current brightness value to be able
  56                  * to restore it when the delay_off period is over.
  57                  */
  58                 led_cdev->blink_brightness = brightness;
  59                 brightness = LED_OFF;
  60                 delay = led_cdev->blink_delay_off;
  61         }
  62
  63         led_set_brightness_async(led_cdev, brightness);
  64
  65         /* Return in next iteration if led is in one-shot mode and we are in
  66          * the final blink state so that the led is toggled each delay_on +
  67          * delay_off milliseconds in worst case.
  68          */
  69         if (led_cdev->flags & LED_BLINK_ONESHOT) {
  70                 if (led_cdev->flags & LED_BLINK_INVERT) {
  71                         if (brightness)
  72                                 led_cdev->flags |= LED_BLINK_ONESHOT_STOP;
  73                 } else {
  74                         if (!brightness)
  75                                 led_cdev->flags |= LED_BLINK_ONESHOT_STOP;
  76                 }
  77         }
  78
  79         mod_timer(&led_cdev->blink_timer, jiffies + msecs_to_jiffies(delay));
  80 }
  81
  82 static void set_brightness_delayed(struct work_struct *ws)
  83 {
  84         struct led_classdev *led_cdev =
  85                 container_of(ws, struct led_classdev, set_brightness_work);
  86
  87         led_stop_software_blink(led_cdev);
  88
  89         led_set_brightness_async(led_cdev, led_cdev->delayed_set_value);
  90 }
  91
  92 static void led_set_software_blink(struct led_classdev *led_cdev,
  93                                    unsigned long delay_on,
  94                                    unsigned long delay_off)
  95 {
  96         int current_brightness;
  97
  98         current_brightness = led_get_brightness(led_cdev);
  99         if (current_brightness)
 100                 led_cdev->blink_brightness = current_brightness;
 101         if (!led_cdev->blink_brightness)
 102                 led_cdev->blink_brightness = led_cdev->max_brightness;
 103
 104         led_cdev->blink_delay_on = delay_on;
 105         led_cdev->blink_delay_off = delay_off;
 106
 107         /* never on - just set to off */
 108         if (!delay_on) {
 109                 led_set_brightness_async(led_cdev, LED_OFF);
 110                 return;
 111         }
 112
 113         /* never off - just set to brightness */
 114         if (!delay_off) {
 115                 led_set_brightness_async(led_cdev, led_cdev->blink_brightness);
 116                 return;
 117         }
 118
 119         mod_timer(&led_cdev->blink_timer, jiffies + 1);
 120 }
 121
 122
 123 static void led_blink_setup(struct led_classdev *led_cdev,
 124                      unsigned long *delay_on,
 125                      unsigned long *delay_off)
 126 {
 127         if (!(led_cdev->flags & LED_BLINK_ONESHOT) &&
 128             led_cdev->blink_set &&
 129             !led_cdev->blink_set(led_cdev, delay_on, delay_off))
 130                 return;
 131
 132         /* blink with 1 Hz as default if nothing specified */
 133         if (!*delay_on && !*delay_off)
 134                 *delay_on = *delay_off = 500;
 135
 136         led_set_software_blink(led_cdev, *delay_on, *delay_off);
 137 }
 138
 139 void led_init_core(struct led_classdev *led_cdev)
 140 {
 141         INIT_WORK(&led_cdev->set_brightness_work, set_brightness_delayed);
 142
 143         setup_timer(&led_cdev->blink_timer, led_timer_function,
 144                     (unsigned long)led_cdev);
 145 }
 146 EXPORT_SYMBOL_GPL(led_init_core);
 147
 148 void led_blink_set(struct led_classdev *led_cdev,
 149                    unsigned long *delay_on,
 150                    unsigned long *delay_off)
 151 {
 152         del_timer_sync(&led_cdev->blink_timer);
 153
 154         led_cdev->flags &= ~LED_BLINK_ONESHOT;
 155         led_cdev->flags &= ~LED_BLINK_ONESHOT_STOP;
 156
 157         led_blink_setup(led_cdev, delay_on, delay_off);
 158 }
 159 EXPORT_SYMBOL(led_blink_set);
 160
 161 void led_blink_set_oneshot(struct led_classdev *led_cdev,
 162                            unsigned long *delay_on,
 163                            unsigned long *delay_off,
 164                            int invert)
 165 {
 166         if ((led_cdev->flags & LED_BLINK_ONESHOT) &&
 167              timer_pending(&led_cdev->blink_timer))
 168                 return;
 169
 170         led_cdev->flags |= LED_BLINK_ONESHOT;
 171         led_cdev->flags &= ~LED_BLINK_ONESHOT_STOP;
 172
 173         if (invert)
 174                 led_cdev->flags |= LED_BLINK_INVERT;
 175         else
 176                 led_cdev->flags &= ~LED_BLINK_INVERT;
 177
 178         led_blink_setup(led_cdev, delay_on, delay_off);
 179 }
 180 EXPORT_SYMBOL(led_blink_set_oneshot);
 181
 182 void led_stop_software_blink(struct led_classdev *led_cdev)
 183 {
 184         del_timer_sync(&led_cdev->blink_timer);
 185         led_cdev->blink_delay_on = 0;
 186         led_cdev->blink_delay_off = 0;
 187 }
 188 EXPORT_SYMBOL_GPL(led_stop_software_blink);
 189
 190 void led_set_brightness(struct led_classdev *led_cdev,
 191                         enum led_brightness brightness)
 192 {
 193         int ret = 0;
 194
 195         /* delay brightness if soft-blink is active */
 196         if (led_cdev->blink_delay_on || led_cdev->blink_delay_off) {
 197                 led_cdev->delayed_set_value = brightness;
 198                 if (brightness == LED_OFF)
 199                         schedule_work(&led_cdev->set_brightness_work);
 200                 return;
 201         }
 202
 203         if (led_cdev->flags & SET_BRIGHTNESS_ASYNC) {
 204                 led_set_brightness_async(led_cdev, brightness);
 205                 return;
 206         } else if (led_cdev->flags & SET_BRIGHTNESS_SYNC)
 207                 ret = led_set_brightness_sync(led_cdev, brightness);
 208         else
 209                 ret = -EINVAL;
 210
 211         if (ret < 0)
 212                 dev_dbg(led_cdev->dev, "Setting LED brightness failed (%d)\n",
 213                         ret);
 214 }
 215 EXPORT_SYMBOL(led_set_brightness);
 216
 217 int led_update_brightness(struct led_classdev *led_cdev)
 218 {
 219         int ret = 0;
 220
 221         if (led_cdev->brightness_get) {
 222                 ret = led_cdev->brightness_get(led_cdev);
 223                 if (ret >= 0) {
 224                         led_cdev->brightness = ret;
 225                         return 0;
 226                 }
 227         }
 228
 229         return ret;
 230 }
 231 EXPORT_SYMBOL(led_update_brightness);
 232
 233 /* Caller must ensure led_cdev->led_access held */
 234 void led_sysfs_disable(struct led_classdev *led_cdev)
 235 {
 236         lockdep_assert_held(&led_cdev->led_access);
 237
 238         led_cdev->flags |= LED_SYSFS_DISABLE;
 239 }
 240 EXPORT_SYMBOL_GPL(led_sysfs_disable);
 241
 242 /* Caller must ensure led_cdev->led_access held */
 243 void led_sysfs_enable(struct led_classdev *led_cdev)
 244 {
 245         lockdep_assert_held(&led_cdev->led_access);
 246
 247         led_cdev->flags &= ~LED_SYSFS_DISABLE;
 248 }
 249 EXPORT_SYMBOL_GPL(led_sysfs_enable);