ac05a928f7642a54a51a0627e6ca7dc904511d09
[linux-3.10.git] / drivers / leds / led-class.c
1 /*
2  * LED Class Core
3  *
4  * Copyright (C) 2005 John Lenz <lenz@cs.wisc.edu>
5  * Copyright (C) 2005-2007 Richard Purdie <rpurdie@openedhand.com>
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License version 2 as
9  * published by the Free Software Foundation.
10  */
11
12 #include <linux/module.h>
13 #include <linux/kernel.h>
14 #include <linux/init.h>
15 #include <linux/list.h>
16 #include <linux/spinlock.h>
17 #include <linux/device.h>
18 #include <linux/sysdev.h>
19 #include <linux/timer.h>
20 #include <linux/err.h>
21 #include <linux/ctype.h>
22 #include <linux/leds.h>
23 #include "leds.h"
24
25 static struct class *leds_class;
26
27 static void led_update_brightness(struct led_classdev *led_cdev)
28 {
29         if (led_cdev->brightness_get)
30                 led_cdev->brightness = led_cdev->brightness_get(led_cdev);
31 }
32
33 static ssize_t led_brightness_show(struct device *dev, 
34                 struct device_attribute *attr, char *buf)
35 {
36         struct led_classdev *led_cdev = dev_get_drvdata(dev);
37         ssize_t ret = 0;
38
39         /* no lock needed for this */
40         led_update_brightness(led_cdev);
41         sprintf(buf, "%u\n", led_cdev->brightness);
42         ret = strlen(buf) + 1;
43
44         return ret;
45 }
46
47 static ssize_t led_brightness_store(struct device *dev,
48                 struct device_attribute *attr, const char *buf, size_t size)
49 {
50         struct led_classdev *led_cdev = dev_get_drvdata(dev);
51         ssize_t ret = -EINVAL;
52         char *after;
53         unsigned long state = simple_strtoul(buf, &after, 10);
54         size_t count = after - buf;
55
56         if (*after && isspace(*after))
57                 count++;
58
59         if (count == size) {
60                 ret = count;
61
62                 if (state == LED_OFF)
63                         led_trigger_remove(led_cdev);
64                 led_set_brightness(led_cdev, state);
65         }
66
67         return ret;
68 }
69
70 static DEVICE_ATTR(brightness, 0644, led_brightness_show, led_brightness_store);
71 #ifdef CONFIG_LEDS_TRIGGERS
72 static DEVICE_ATTR(trigger, 0644, led_trigger_show, led_trigger_store);
73 #endif
74
75 /**
76  * led_classdev_suspend - suspend an led_classdev.
77  * @led_cdev: the led_classdev to suspend.
78  */
79 void led_classdev_suspend(struct led_classdev *led_cdev)
80 {
81         led_cdev->flags |= LED_SUSPENDED;
82         led_cdev->brightness_set(led_cdev, 0);
83 }
84 EXPORT_SYMBOL_GPL(led_classdev_suspend);
85
86 /**
87  * led_classdev_resume - resume an led_classdev.
88  * @led_cdev: the led_classdev to resume.
89  */
90 void led_classdev_resume(struct led_classdev *led_cdev)
91 {
92         led_cdev->brightness_set(led_cdev, led_cdev->brightness);
93         led_cdev->flags &= ~LED_SUSPENDED;
94 }
95 EXPORT_SYMBOL_GPL(led_classdev_resume);
96
97 /**
98  * led_classdev_register - register a new object of led_classdev class.
99  * @dev: The device to register.
100  * @led_cdev: the led_classdev structure for this device.
101  */
102 int led_classdev_register(struct device *parent, struct led_classdev *led_cdev)
103 {
104         int rc;
105
106         led_cdev->dev = device_create(leds_class, parent, 0, "%s",
107                                             led_cdev->name);
108         if (unlikely(IS_ERR(led_cdev->dev)))
109                 return PTR_ERR(led_cdev->dev);
110
111         dev_set_drvdata(led_cdev->dev, led_cdev);
112
113         /* register the attributes */
114         rc = device_create_file(led_cdev->dev, &dev_attr_brightness);
115         if (rc)
116                 goto err_out;
117
118         /* add to the list of leds */
119         down_write(&leds_list_lock);
120         list_add_tail(&led_cdev->node, &leds_list);
121         up_write(&leds_list_lock);
122
123         led_update_brightness(led_cdev);
124
125 #ifdef CONFIG_LEDS_TRIGGERS
126         init_rwsem(&led_cdev->trigger_lock);
127
128         rc = device_create_file(led_cdev->dev, &dev_attr_trigger);
129         if (rc)
130                 goto err_out_led_list;
131
132         led_trigger_set_default(led_cdev);
133 #endif
134
135         printk(KERN_INFO "Registered led device: %s\n",
136                         led_cdev->name);
137
138         return 0;
139
140 #ifdef CONFIG_LEDS_TRIGGERS
141 err_out_led_list:
142         device_remove_file(led_cdev->dev, &dev_attr_brightness);
143         list_del(&led_cdev->node);
144 #endif
145 err_out:
146         device_unregister(led_cdev->dev);
147         return rc;
148 }
149 EXPORT_SYMBOL_GPL(led_classdev_register);
150
151 /**
152  * __led_classdev_unregister - unregisters a object of led_properties class.
153  * @led_cdev: the led device to unregister
154  *
155  * Unregisters a previously registered via led_classdev_register object.
156  */
157 void led_classdev_unregister(struct led_classdev *led_cdev)
158 {
159         device_remove_file(led_cdev->dev, &dev_attr_brightness);
160 #ifdef CONFIG_LEDS_TRIGGERS
161         device_remove_file(led_cdev->dev, &dev_attr_trigger);
162         down_write(&led_cdev->trigger_lock);
163         if (led_cdev->trigger)
164                 led_trigger_set(led_cdev, NULL);
165         up_write(&led_cdev->trigger_lock);
166 #endif
167
168         device_unregister(led_cdev->dev);
169
170         down_write(&leds_list_lock);
171         list_del(&led_cdev->node);
172         up_write(&leds_list_lock);
173 }
174 EXPORT_SYMBOL_GPL(led_classdev_unregister);
175
176 static int __init leds_init(void)
177 {
178         leds_class = class_create(THIS_MODULE, "leds");
179         if (IS_ERR(leds_class))
180                 return PTR_ERR(leds_class);
181         return 0;
182 }
183
184 static void __exit leds_exit(void)
185 {
186         class_destroy(leds_class);
187 }
188
189 subsys_initcall(leds_init);
190 module_exit(leds_exit);
191
192 MODULE_AUTHOR("John Lenz, Richard Purdie");
193 MODULE_LICENSE("GPL");
194 MODULE_DESCRIPTION("LED Class Interface");