Pull esi-support into release branch
[linux-2.6] / drivers / leds / led-triggers.c
1 /*
2  * LED Triggers 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/module.h>
15 #include <linux/kernel.h>
16 #include <linux/init.h>
17 #include <linux/list.h>
18 #include <linux/spinlock.h>
19 #include <linux/device.h>
20 #include <linux/sysdev.h>
21 #include <linux/timer.h>
22 #include <linux/leds.h>
23 #include "leds.h"
24
25 /*
26  * Nests outside led_cdev->trigger_lock
27  */
28 static DEFINE_RWLOCK(triggers_list_lock);
29 static LIST_HEAD(trigger_list);
30
31 ssize_t led_trigger_store(struct class_device *dev, const char *buf,
32                         size_t count)
33 {
34         struct led_classdev *led_cdev = class_get_devdata(dev);
35         char trigger_name[TRIG_NAME_MAX];
36         struct led_trigger *trig;
37         size_t len;
38
39         trigger_name[sizeof(trigger_name) - 1] = '\0';
40         strncpy(trigger_name, buf, sizeof(trigger_name) - 1);
41         len = strlen(trigger_name);
42
43         if (len && trigger_name[len - 1] == '\n')
44                 trigger_name[len - 1] = '\0';
45
46         if (!strcmp(trigger_name, "none")) {
47                 write_lock(&led_cdev->trigger_lock);
48                 led_trigger_set(led_cdev, NULL);
49                 write_unlock(&led_cdev->trigger_lock);
50                 return count;
51         }
52
53         read_lock(&triggers_list_lock);
54         list_for_each_entry(trig, &trigger_list, next_trig) {
55                 if (!strcmp(trigger_name, trig->name)) {
56                         write_lock(&led_cdev->trigger_lock);
57                         led_trigger_set(led_cdev, trig);
58                         write_unlock(&led_cdev->trigger_lock);
59
60                         read_unlock(&triggers_list_lock);
61                         return count;
62                 }
63         }
64         read_unlock(&triggers_list_lock);
65
66         return -EINVAL;
67 }
68
69
70 ssize_t led_trigger_show(struct class_device *dev, char *buf)
71 {
72         struct led_classdev *led_cdev = class_get_devdata(dev);
73         struct led_trigger *trig;
74         int len = 0;
75
76         read_lock(&triggers_list_lock);
77         read_lock(&led_cdev->trigger_lock);
78
79         if (!led_cdev->trigger)
80                 len += sprintf(buf+len, "[none] ");
81         else
82                 len += sprintf(buf+len, "none ");
83
84         list_for_each_entry(trig, &trigger_list, next_trig) {
85                 if (led_cdev->trigger && !strcmp(led_cdev->trigger->name,
86                                                         trig->name))
87                         len += sprintf(buf+len, "[%s] ", trig->name);
88                 else
89                         len += sprintf(buf+len, "%s ", trig->name);
90         }
91         read_unlock(&led_cdev->trigger_lock);
92         read_unlock(&triggers_list_lock);
93
94         len += sprintf(len+buf, "\n");
95         return len;
96 }
97
98 void led_trigger_event(struct led_trigger *trigger,
99                         enum led_brightness brightness)
100 {
101         struct list_head *entry;
102
103         if (!trigger)
104                 return;
105
106         read_lock(&trigger->leddev_list_lock);
107         list_for_each(entry, &trigger->led_cdevs) {
108                 struct led_classdev *led_cdev;
109
110                 led_cdev = list_entry(entry, struct led_classdev, trig_list);
111                 led_set_brightness(led_cdev, brightness);
112         }
113         read_unlock(&trigger->leddev_list_lock);
114 }
115
116 /* Caller must ensure led_cdev->trigger_lock held */
117 void led_trigger_set(struct led_classdev *led_cdev, struct led_trigger *trigger)
118 {
119         unsigned long flags;
120
121         /* Remove any existing trigger */
122         if (led_cdev->trigger) {
123                 write_lock_irqsave(&led_cdev->trigger->leddev_list_lock, flags);
124                 list_del(&led_cdev->trig_list);
125                 write_unlock_irqrestore(&led_cdev->trigger->leddev_list_lock, flags);
126                 if (led_cdev->trigger->deactivate)
127                         led_cdev->trigger->deactivate(led_cdev);
128         }
129         if (trigger) {
130                 write_lock_irqsave(&trigger->leddev_list_lock, flags);
131                 list_add_tail(&led_cdev->trig_list, &trigger->led_cdevs);
132                 write_unlock_irqrestore(&trigger->leddev_list_lock, flags);
133                 if (trigger->activate)
134                         trigger->activate(led_cdev);
135         }
136         led_cdev->trigger = trigger;
137 }
138
139 void led_trigger_set_default(struct led_classdev *led_cdev)
140 {
141         struct led_trigger *trig;
142
143         if (!led_cdev->default_trigger)
144                 return;
145
146         read_lock(&triggers_list_lock);
147         write_lock(&led_cdev->trigger_lock);
148         list_for_each_entry(trig, &trigger_list, next_trig) {
149                 if (!strcmp(led_cdev->default_trigger, trig->name))
150                         led_trigger_set(led_cdev, trig);
151         }
152         write_unlock(&led_cdev->trigger_lock);
153         read_unlock(&triggers_list_lock);
154 }
155
156 int led_trigger_register(struct led_trigger *trigger)
157 {
158         struct led_classdev *led_cdev;
159
160         rwlock_init(&trigger->leddev_list_lock);
161         INIT_LIST_HEAD(&trigger->led_cdevs);
162
163         /* Add to the list of led triggers */
164         write_lock(&triggers_list_lock);
165         list_add_tail(&trigger->next_trig, &trigger_list);
166         write_unlock(&triggers_list_lock);
167
168         /* Register with any LEDs that have this as a default trigger */
169         read_lock(&leds_list_lock);
170         list_for_each_entry(led_cdev, &leds_list, node) {
171                 write_lock(&led_cdev->trigger_lock);
172                 if (!led_cdev->trigger && led_cdev->default_trigger &&
173                             !strcmp(led_cdev->default_trigger, trigger->name))
174                         led_trigger_set(led_cdev, trigger);
175                 write_unlock(&led_cdev->trigger_lock);
176         }
177         read_unlock(&leds_list_lock);
178
179         return 0;
180 }
181
182 void led_trigger_register_simple(const char *name, struct led_trigger **tp)
183 {
184         struct led_trigger *trigger;
185
186         trigger = kzalloc(sizeof(struct led_trigger), GFP_KERNEL);
187
188         if (trigger) {
189                 trigger->name = name;
190                 led_trigger_register(trigger);
191         }
192         *tp = trigger;
193 }
194
195 void led_trigger_unregister(struct led_trigger *trigger)
196 {
197         struct led_classdev *led_cdev;
198
199         /* Remove from the list of led triggers */
200         write_lock(&triggers_list_lock);
201         list_del(&trigger->next_trig);
202         write_unlock(&triggers_list_lock);
203
204         /* Remove anyone actively using this trigger */
205         read_lock(&leds_list_lock);
206         list_for_each_entry(led_cdev, &leds_list, node) {
207                 write_lock(&led_cdev->trigger_lock);
208                 if (led_cdev->trigger == trigger)
209                         led_trigger_set(led_cdev, NULL);
210                 write_unlock(&led_cdev->trigger_lock);
211         }
212         read_unlock(&leds_list_lock);
213 }
214
215 void led_trigger_unregister_simple(struct led_trigger *trigger)
216 {
217         led_trigger_unregister(trigger);
218         kfree(trigger);
219 }
220
221 /* Used by LED Class */
222 EXPORT_SYMBOL_GPL(led_trigger_set);
223 EXPORT_SYMBOL_GPL(led_trigger_set_default);
224 EXPORT_SYMBOL_GPL(led_trigger_show);
225 EXPORT_SYMBOL_GPL(led_trigger_store);
226
227 /* LED Trigger Interface */
228 EXPORT_SYMBOL_GPL(led_trigger_register);
229 EXPORT_SYMBOL_GPL(led_trigger_unregister);
230
231 /* Simple LED Tigger Interface */
232 EXPORT_SYMBOL_GPL(led_trigger_register_simple);
233 EXPORT_SYMBOL_GPL(led_trigger_unregister_simple);
234 EXPORT_SYMBOL_GPL(led_trigger_event);
235
236 MODULE_AUTHOR("Richard Purdie");
237 MODULE_LICENSE("GPL");
238 MODULE_DESCRIPTION("LED Triggers Core");