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_nosleep(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                 brightness = led_cdev->blink_brightness;
  48                 delay = led_cdev->blink_delay_on;
  49         } else {
  50                 /* Store the current brightness value to be able
  51                  * to restore it when the delay_off period is over.
  52                  * Do it only if there is no pending blink brightness
  53                  * change, to avoid overwriting the new value.
  54                  */
  55                 if (!(led_cdev->flags & LED_BLINK_BRIGHTNESS_CHANGE))
  56                         led_cdev->blink_brightness = brightness;
  57                 else
  58                         led_cdev->flags &= ~LED_BLINK_BRIGHTNESS_CHANGE;
  59                 brightness = LED_OFF;
  60                 delay = led_cdev->blink_delay_off;
  61         }
  62
  63         led_set_brightness_nosleep(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         if (led_cdev->flags & LED_BLINK_DISABLE) {
  88                 led_cdev->delayed_set_value = LED_OFF;
  89                 led_stop_software_blink(led_cdev);
  90                 led_cdev->flags &= ~LED_BLINK_DISABLE;
  91         }
  92
  93         led_set_brightness_async(led_cdev, led_cdev->delayed_set_value);
  94 }
  95
  96 static void led_set_software_blink(struct led_classdev *led_cdev,
  97                                    unsigned long delay_on,
  98                                    unsigned long delay_off)
  99 {
 100         int current_brightness;
 101
 102         current_brightness = led_get_brightness(led_cdev);
 103         if (current_brightness)
 104                 led_cdev->blink_brightness = current_brightness;
 105         if (!led_cdev->blink_brightness)
 106                 led_cdev->blink_brightness = led_cdev->max_brightness;
 107
 108         led_cdev->blink_delay_on = delay_on;
 109         led_cdev->blink_delay_off = delay_off;
 110
 111         /* never on - just set to off */
 112         if (!delay_on) {
 113                 led_set_brightness_nosleep(led_cdev, LED_OFF);
 114                 return;
 115         }
 116
 117         /* never off - just set to brightness */
 118         if (!delay_off) {
 119                 led_set_brightness_nosleep(led_cdev,
 120                                            led_cdev->blink_brightness);
 121                 return;
 122         }
 123
 124         mod_timer(&led_cdev->blink_timer, jiffies + 1);
 125 }
 126
 127
 128 static void led_blink_setup(struct led_classdev *led_cdev,
 129                      unsigned long *delay_on,
 130                      unsigned long *delay_off)
 131 {
 132         if (!(led_cdev->flags & LED_BLINK_ONESHOT) &&
 133             led_cdev->blink_set &&
 134             !led_cdev->blink_set(led_cdev, delay_on, delay_off))
 135                 return;
 136
 137         /* blink with 1 Hz as default if nothing specified */
 138         if (!*delay_on && !*delay_off)
 139                 *delay_on = *delay_off = 500;
 140
 141         led_set_software_blink(led_cdev, *delay_on, *delay_off);
 142 }
 143
 144 void led_init_core(struct led_classdev *led_cdev)
 145 {
 146         INIT_WORK(&led_cdev->set_brightness_work, set_brightness_delayed);
 147
 148         setup_timer(&led_cdev->blink_timer, led_timer_function,
 149                     (unsigned long)led_cdev);
 150 }
 151 EXPORT_SYMBOL_GPL(led_init_core);
 152
 153 void led_blink_set(struct led_classdev *led_cdev,
 154                    unsigned long *delay_on,
 155                    unsigned long *delay_off)
 156 {
 157         del_timer_sync(&led_cdev->blink_timer);
 158
 159         led_cdev->flags &= ~LED_BLINK_ONESHOT;
 160         led_cdev->flags &= ~LED_BLINK_ONESHOT_STOP;
 161
 162         led_blink_setup(led_cdev, delay_on, delay_off);
 163 }
 164 EXPORT_SYMBOL_GPL(led_blink_set);
 165
 166 void led_blink_set_oneshot(struct led_classdev *led_cdev,
 167                            unsigned long *delay_on,
 168                            unsigned long *delay_off,
 169                            int invert)
 170 {
 171         if ((led_cdev->flags & LED_BLINK_ONESHOT) &&
 172              timer_pending(&led_cdev->blink_timer))
 173                 return;
 174
 175         led_cdev->flags |= LED_BLINK_ONESHOT;
 176         led_cdev->flags &= ~LED_BLINK_ONESHOT_STOP;
 177
 178         if (invert)
 179                 led_cdev->flags |= LED_BLINK_INVERT;
 180         else
 181                 led_cdev->flags &= ~LED_BLINK_INVERT;
 182
 183         led_blink_setup(led_cdev, delay_on, delay_off);
 184 }
 185 EXPORT_SYMBOL_GPL(led_blink_set_oneshot);
 186
 187 void led_stop_software_blink(struct led_classdev *led_cdev)
 188 {
 189         del_timer_sync(&led_cdev->blink_timer);
 190         led_cdev->blink_delay_on = 0;
 191         led_cdev->blink_delay_off = 0;
 192 }
 193 EXPORT_SYMBOL_GPL(led_stop_software_blink);
 194
 195 void led_set_brightness(struct led_classdev *led_cdev,
 196                         enum led_brightness brightness)
 197 {
 198         int ret = 0;
 199
 200         /*
 201          * In case blinking is on delay brightness setting
 202          * until the next timer tick.
 203          */
 204         if (led_cdev->blink_delay_on || led_cdev->blink_delay_off) {
 205                 /*
 206                  * If we need to disable soft blinking delegate this to the
 207                  * work queue task to avoid problems in case we are called
 208                  * from hard irq context.
 209                  */
 210                 if (brightness == LED_OFF) {
 211                         led_cdev->flags |= LED_BLINK_DISABLE;
 212                         schedule_work(&led_cdev->set_brightness_work);
 213                 } else {
 214                         led_cdev->flags |= LED_BLINK_BRIGHTNESS_CHANGE;
 215                         led_cdev->blink_brightness = brightness;
 216                 }
 217                 return;
 218         }
 219
 220         if (led_cdev->flags & SET_BRIGHTNESS_ASYNC) {
 221                 led_set_brightness_nosleep(led_cdev, brightness);
 222                 return;
 223         } else if (led_cdev->flags & SET_BRIGHTNESS_SYNC)
 224                 ret = led_set_brightness_sync(led_cdev, brightness);
 225         else
 226                 ret = -EINVAL;
 227
 228         if (ret < 0)
 229                 dev_dbg(led_cdev->dev, "Setting LED brightness failed (%d)\n",
 230                         ret);
 231 }
 232 EXPORT_SYMBOL_GPL(led_set_brightness);
 233
 234 void led_set_brightness_nopm(struct led_classdev *led_cdev,
 235                               enum led_brightness value)
 236 {
 237         /* Use brightness_set op if available, it is guaranteed not to sleep */
 238         if (led_cdev->brightness_set) {
 239                 led_cdev->brightness_set(led_cdev, value);
 240                 return;
 241         }
 242
 243         /* If brightness setting can sleep, delegate it to a work queue task */
 244         led_cdev->delayed_set_value = value;
 245         schedule_work(&led_cdev->set_brightness_work);
 246 }
 247 EXPORT_SYMBOL_GPL(led_set_brightness_nopm);
 248
 249 void led_set_brightness_nosleep(struct led_classdev *led_cdev,
 250                                 enum led_brightness value)
 251 {
 252         led_cdev->brightness = min(value, led_cdev->max_brightness);
 253
 254         if (led_cdev->flags & LED_SUSPENDED)
 255                 return;
 256
 257         led_set_brightness_nopm(led_cdev, led_cdev->brightness);
 258 }
 259 EXPORT_SYMBOL_GPL(led_set_brightness_nosleep);
 260
 261 int led_update_brightness(struct led_classdev *led_cdev)
 262 {
 263         int ret = 0;
 264
 265         if (led_cdev->brightness_get) {
 266                 ret = led_cdev->brightness_get(led_cdev);
 267                 if (ret >= 0) {
 268                         led_cdev->brightness = ret;
 269                         return 0;
 270                 }
 271         }
 272
 273         return ret;
 274 }
 275 EXPORT_SYMBOL_GPL(led_update_brightness);
 276
 277 /* Caller must ensure led_cdev->led_access held */
 278 void led_sysfs_disable(struct led_classdev *led_cdev)
 279 {
 280         lockdep_assert_held(&led_cdev->led_access);
 281
 282         led_cdev->flags |= LED_SYSFS_DISABLE;
 283 }
 284 EXPORT_SYMBOL_GPL(led_sysfs_disable);
 285
 286 /* Caller must ensure led_cdev->led_access held */
 287 void led_sysfs_enable(struct led_classdev *led_cdev)
 288 {
 289         lockdep_assert_held(&led_cdev->led_access);
 290
 291         led_cdev->flags &= ~LED_SYSFS_DISABLE;
 292 }
 293 EXPORT_SYMBOL_GPL(led_sysfs_enable);