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_stop_software_blink(struct led_classdev *led_cdev)
  28 {
  29         /* deactivate previous settings */
  30         del_timer_sync(&led_cdev->blink_timer);
  31         led_cdev->blink_delay_on = 0;
  32         led_cdev->blink_delay_off = 0;
  33 }
  34
  35 static void led_set_software_blink(struct led_classdev *led_cdev,
  36                                    unsigned long delay_on,
  37                                    unsigned long delay_off)
  38 {
  39         int current_brightness;
  40
  41         current_brightness = led_get_brightness(led_cdev);
  42         if (current_brightness)
  43                 led_cdev->blink_brightness = current_brightness;
  44         if (!led_cdev->blink_brightness)
  45                 led_cdev->blink_brightness = led_cdev->max_brightness;
  46
  47         if (led_get_trigger_data(led_cdev) &&
  48             delay_on == led_cdev->blink_delay_on &&
  49             delay_off == led_cdev->blink_delay_off)
  50                 return;
  51
  52         led_stop_software_blink(led_cdev);
  53
  54         led_cdev->blink_delay_on = delay_on;
  55         led_cdev->blink_delay_off = delay_off;
  56
  57         /* never on - don't blink */
  58         if (!delay_on)
  59                 return;
  60
  61         /* never off - just set to brightness */
  62         if (!delay_off) {
  63                 led_set_brightness(led_cdev, led_cdev->blink_brightness);
  64                 return;
  65         }
  66
  67         mod_timer(&led_cdev->blink_timer, jiffies + 1);
  68 }
  69
  70
  71 void led_blink_set(struct led_classdev *led_cdev,
  72                    unsigned long *delay_on,
  73                    unsigned long *delay_off)
  74 {
  75         del_timer_sync(&led_cdev->blink_timer);
  76
  77         if (led_cdev->blink_set &&
  78             !led_cdev->blink_set(led_cdev, delay_on, delay_off))
  79                 return;
  80
  81         /* blink with 1 Hz as default if nothing specified */
  82         if (!*delay_on && !*delay_off)
  83                 *delay_on = *delay_off = 500;
  84
  85         led_set_software_blink(led_cdev, *delay_on, *delay_off);
  86 }
  87 EXPORT_SYMBOL(led_blink_set);
  88
  89 void led_brightness_set(struct led_classdev *led_cdev,
  90                         enum led_brightness brightness)
  91 {
  92         led_stop_software_blink(led_cdev);
  93         led_cdev->brightness_set(led_cdev, brightness);
  94 }
  95 EXPORT_SYMBOL(led_brightness_set);