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/list.h>
  16 #include <linux/module.h>
  17 #include <linux/rwsem.h>
  18 #include <linux/leds.h>
  19 #include "leds.h"
  20
  21 DECLARE_RWSEM(leds_list_lock);
  22 EXPORT_SYMBOL_GPL(leds_list_lock);
  23
  24 LIST_HEAD(leds_list);
  25 EXPORT_SYMBOL_GPL(leds_list);
  26
  27 static void led_set_software_blink(struct led_classdev *led_cdev,
  28                                    unsigned long delay_on,
  29                                    unsigned long delay_off)
  30 {
  31         int current_brightness;
  32
  33         current_brightness = led_get_brightness(led_cdev);
  34         if (current_brightness)
  35                 led_cdev->blink_brightness = current_brightness;
  36         if (!led_cdev->blink_brightness)
  37                 led_cdev->blink_brightness = led_cdev->max_brightness;
  38
  39         led_cdev->blink_delay_on = delay_on;
  40         led_cdev->blink_delay_off = delay_off;
  41
  42         /* never on - don't blink */
  43         if (!delay_on)
  44                 return;
  45
  46         /* never off - just set to brightness */
  47         if (!delay_off) {
  48                 __led_set_brightness(led_cdev, led_cdev->blink_brightness);
  49                 return;
  50         }
  51
  52         mod_timer(&led_cdev->blink_timer, jiffies + 1);
  53 }
  54
  55
  56 static void led_blink_setup(struct led_classdev *led_cdev,
  57                      unsigned long *delay_on,
  58                      unsigned long *delay_off)
  59 {
  60         if (!(led_cdev->flags & LED_BLINK_ONESHOT) &&
  61             led_cdev->blink_set &&
  62             !led_cdev->blink_set(led_cdev, delay_on, delay_off))
  63                 return;
  64
  65         /* blink with 1 Hz as default if nothing specified */
  66         if (!*delay_on && !*delay_off)
  67                 *delay_on = *delay_off = 500;
  68
  69         led_set_software_blink(led_cdev, *delay_on, *delay_off);
  70 }
  71
  72 void led_blink_set(struct led_classdev *led_cdev,
  73                    unsigned long *delay_on,
  74                    unsigned long *delay_off)
  75 {
  76         del_timer_sync(&led_cdev->blink_timer);
  77
  78         led_cdev->flags &= ~LED_BLINK_ONESHOT;
  79         led_cdev->flags &= ~LED_BLINK_ONESHOT_STOP;
  80
  81         led_blink_setup(led_cdev, delay_on, delay_off);
  82 }
  83 EXPORT_SYMBOL(led_blink_set);
  84
  85 void led_blink_set_oneshot(struct led_classdev *led_cdev,
  86                            unsigned long *delay_on,
  87                            unsigned long *delay_off,
  88                            int invert)
  89 {
  90         if ((led_cdev->flags & LED_BLINK_ONESHOT) &&
  91              timer_pending(&led_cdev->blink_timer))
  92                 return;
  93
  94         led_cdev->flags |= LED_BLINK_ONESHOT;
  95         led_cdev->flags &= ~LED_BLINK_ONESHOT_STOP;
  96
  97         if (invert)
  98                 led_cdev->flags |= LED_BLINK_INVERT;
  99         else
 100                 led_cdev->flags &= ~LED_BLINK_INVERT;
 101
 102         led_blink_setup(led_cdev, delay_on, delay_off);
 103 }
 104 EXPORT_SYMBOL(led_blink_set_oneshot);
 105
 106 void led_stop_software_blink(struct led_classdev *led_cdev)
 107 {
 108         del_timer_sync(&led_cdev->blink_timer);
 109         led_cdev->blink_delay_on = 0;
 110         led_cdev->blink_delay_off = 0;
 111 }
 112 EXPORT_SYMBOL_GPL(led_stop_software_blink);
 113
 114 void led_set_brightness(struct led_classdev *led_cdev,
 115                         enum led_brightness brightness)
 116 {
 117         /* delay brightness setting if need to stop soft-blink timer */
 118         if (led_cdev->blink_delay_on || led_cdev->blink_delay_off) {
 119                 led_cdev->delayed_set_value = brightness;
 120                 schedule_work(&led_cdev->set_brightness_work);
 121                 return;
 122         }
 123
 124         __led_set_brightness(led_cdev, brightness);
 125 }
 126 EXPORT_SYMBOL(led_set_brightness);