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 - just set to off */
  43         if (!delay_on) {
  44                 __led_set_brightness(led_cdev, LED_OFF);
  45                 return;
  46         }
  47
  48         /* never off - just set to brightness */
  49         if (!delay_off) {
  50                 __led_set_brightness(led_cdev, led_cdev->blink_brightness);
  51                 return;
  52         }
  53
  54         mod_timer(&led_cdev->blink_timer, jiffies + 1);
  55 }
  56
  57
  58 static void led_blink_setup(struct led_classdev *led_cdev,
  59                      unsigned long *delay_on,
  60                      unsigned long *delay_off)
  61 {
  62         if (!(led_cdev->flags & LED_BLINK_ONESHOT) &&
  63             led_cdev->blink_set &&
  64             !led_cdev->blink_set(led_cdev, delay_on, delay_off))
  65                 return;
  66
  67         /* blink with 1 Hz as default if nothing specified */
  68         if (!*delay_on && !*delay_off)
  69                 *delay_on = *delay_off = 500;
  70
  71         led_set_software_blink(led_cdev, *delay_on, *delay_off);
  72 }
  73
  74 void led_blink_set(struct led_classdev *led_cdev,
  75                    unsigned long *delay_on,
  76                    unsigned long *delay_off)
  77 {
  78         del_timer_sync(&led_cdev->blink_timer);
  79
  80         led_cdev->flags &= ~LED_BLINK_ONESHOT;
  81         led_cdev->flags &= ~LED_BLINK_ONESHOT_STOP;
  82
  83         led_blink_setup(led_cdev, delay_on, delay_off);
  84 }
  85 EXPORT_SYMBOL(led_blink_set);
  86
  87 void led_blink_set_oneshot(struct led_classdev *led_cdev,
  88                            unsigned long *delay_on,
  89                            unsigned long *delay_off,
  90                            int invert)
  91 {
  92         if ((led_cdev->flags & LED_BLINK_ONESHOT) &&
  93              timer_pending(&led_cdev->blink_timer))
  94                 return;
  95
  96         led_cdev->flags |= LED_BLINK_ONESHOT;
  97         led_cdev->flags &= ~LED_BLINK_ONESHOT_STOP;
  98
  99         if (invert)
 100                 led_cdev->flags |= LED_BLINK_INVERT;
 101         else
 102                 led_cdev->flags &= ~LED_BLINK_INVERT;
 103
 104         led_blink_setup(led_cdev, delay_on, delay_off);
 105 }
 106 EXPORT_SYMBOL(led_blink_set_oneshot);
 107
 108 void led_stop_software_blink(struct led_classdev *led_cdev)
 109 {
 110         del_timer_sync(&led_cdev->blink_timer);
 111         led_cdev->blink_delay_on = 0;
 112         led_cdev->blink_delay_off = 0;
 113 }
 114 EXPORT_SYMBOL_GPL(led_stop_software_blink);
 115
 116 void led_set_brightness(struct led_classdev *led_cdev,
 117                         enum led_brightness brightness)
 118 {
 119         /* delay brightness setting if need to stop soft-blink timer */
 120         if (led_cdev->blink_delay_on || led_cdev->blink_delay_off) {
 121                 led_cdev->delayed_set_value = brightness;
 122                 schedule_work(&led_cdev->set_brightness_work);
 123                 return;
 124         }
 125
 126         __led_set_brightness(led_cdev, brightness);
 127 }
 128 EXPORT_SYMBOL(led_set_brightness);