xref: /linux/drivers/leds/led-core.c (revision c5aec4c76af1a2d89ee2f2d4d5463b2ad2d85de5)
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);
129