kernel/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_set_software_blink(struct led_classdev *led_cdev,
  29                                    unsigned long delay_on,
  30                                    unsigned long delay_off)
  31 {
  32         int current_brightness;
  33
  34         current_brightness = led_get_brightness(led_cdev);
  35         if (current_brightness)
  36                 led_cdev->blink_brightness = current_brightness;
  37         if (!led_cdev->blink_brightness)
  38                 led_cdev->blink_brightness = led_cdev->max_brightness;
  39
  40         led_cdev->blink_delay_on = delay_on;
  41         led_cdev->blink_delay_off = delay_off;
  42
  43         /* never on - just set to off */
  44         if (!delay_on) {
  45                 led_set_brightness_async(led_cdev, LED_OFF);
  46                 return;
  47         }
  48
  49         /* never off - just set to brightness */
  50         if (!delay_off) {
  51                 led_set_brightness_async(led_cdev, led_cdev->blink_brightness);
  52                 return;
  53         }
  54
  55         mod_timer(&led_cdev->blink_timer, jiffies + 1);
  56 }
  57
  58
  59 static void led_blink_setup(struct led_classdev *led_cdev,
  60                      unsigned long *delay_on,
  61                      unsigned long *delay_off)
  62 {
  63         if (!(led_cdev->flags & LED_BLINK_ONESHOT) &&
  64             led_cdev->blink_set &&
  65             !led_cdev->blink_set(led_cdev, delay_on, delay_off))
  66                 return;
  67
  68         /* blink with 1 Hz as default if nothing specified */
  69         if (!*delay_on && !*delay_off)
  70                 *delay_on = *delay_off = 500;
  71
  72         led_set_software_blink(led_cdev, *delay_on, *delay_off);
  73 }
  74
  75 void led_blink_set(struct led_classdev *led_cdev,
  76                    unsigned long *delay_on,
  77                    unsigned long *delay_off)
  78 {
  79         del_timer_sync(&led_cdev->blink_timer);
  80
  81         led_cdev->flags &= ~LED_BLINK_ONESHOT;
  82         led_cdev->flags &= ~LED_BLINK_ONESHOT_STOP;
  83
  84         led_blink_setup(led_cdev, delay_on, delay_off);
  85 }
  86 EXPORT_SYMBOL(led_blink_set);
  87
  88 void led_blink_set_oneshot(struct led_classdev *led_cdev,
  89                            unsigned long *delay_on,
  90                            unsigned long *delay_off,
  91                            int invert)
  92 {
  93         if ((led_cdev->flags & LED_BLINK_ONESHOT) &&
  94              timer_pending(&led_cdev->blink_timer))
  95                 return;
  96
  97         led_cdev->flags |= LED_BLINK_ONESHOT;
  98         led_cdev->flags &= ~LED_BLINK_ONESHOT_STOP;
  99
 100         if (invert)
 101                 led_cdev->flags |= LED_BLINK_INVERT;
 102         else
 103                 led_cdev->flags &= ~LED_BLINK_INVERT;
 104
 105         led_blink_setup(led_cdev, delay_on, delay_off);
 106 }
 107 EXPORT_SYMBOL(led_blink_set_oneshot);
 108
 109 void led_stop_software_blink(struct led_classdev *led_cdev)
 110 {
 111         del_timer_sync(&led_cdev->blink_timer);
 112         led_cdev->blink_delay_on = 0;
 113         led_cdev->blink_delay_off = 0;
 114 }
 115 EXPORT_SYMBOL_GPL(led_stop_software_blink);
 116
 117 void led_set_brightness(struct led_classdev *led_cdev,
 118                         enum led_brightness brightness)
 119 {
 120         int ret = 0;
 121
 122         /* delay brightness setting if need to stop soft-blink timer */
 123         if (led_cdev->blink_delay_on || led_cdev->blink_delay_off) {
 124                 led_cdev->delayed_set_value = brightness;
 125                 schedule_work(&led_cdev->set_brightness_work);
 126                 return;
 127         }
 128
 129         if (led_cdev->flags & SET_BRIGHTNESS_ASYNC) {
 130                 led_set_brightness_async(led_cdev, brightness);
 131                 return;
 132         } else if (led_cdev->flags & SET_BRIGHTNESS_SYNC)
 133                 ret = led_set_brightness_sync(led_cdev, brightness);
 134         else
 135                 ret = -EINVAL;
 136
 137         if (ret < 0)
 138                 dev_dbg(led_cdev->dev, "Setting LED brightness failed (%d)\n",
 139                         ret);
 140 }
 141 EXPORT_SYMBOL(led_set_brightness);
 142
 143 int led_update_brightness(struct led_classdev *led_cdev)
 144 {
 145         int ret = 0;
 146
 147         if (led_cdev->brightness_get) {
 148                 ret = led_cdev->brightness_get(led_cdev);
 149                 if (ret >= 0) {
 150                         led_cdev->brightness = ret;
 151                         return 0;
 152                 }
 153         }
 154
 155         return ret;
 156 }
 157 EXPORT_SYMBOL(led_update_brightness);
 158
 159 /* Caller must ensure led_cdev->led_access held */
 160 void led_sysfs_disable(struct led_classdev *led_cdev)
 161 {
 162         lockdep_assert_held(&led_cdev->led_access);
 163
 164         led_cdev->flags |= LED_SYSFS_DISABLE;
 165 }
 166 EXPORT_SYMBOL_GPL(led_sysfs_disable);
 167
 168 /* Caller must ensure led_cdev->led_access held */
 169 void led_sysfs_enable(struct led_classdev *led_cdev)
 170 {
 171         lockdep_assert_held(&led_cdev->led_access);
 172
 173         led_cdev->flags &= ~LED_SYSFS_DISABLE;
 174 }
 175 EXPORT_SYMBOL_GPL(led_sysfs_enable);