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/config.h>
15 #include <linux/module.h>
16 #include <linux/kernel.h>
17 #include <linux/init.h>
18 #include <linux/list.h>
19 #include <linux/spinlock.h>
20 #include <linux/device.h>
21 #include <linux/sysdev.h>
22 #include <linux/timer.h>
23 #include <linux/leds.h>
24 #include "leds.h"
25
26 /*
27 * Nests outside led_cdev->trigger_lock
28 */
29 static rwlock_t triggers_list_lock = RW_LOCK_UNLOCKED;
30 static LIST_HEAD(trigger_list);
31
32 ssize_t led_trigger_store(struct class_device *dev, const char *buf,
33 size_t count)
34 {
35 struct led_classdev *led_cdev = class_get_devdata(dev);
36 char trigger_name[TRIG_NAME_MAX];
37 struct led_trigger *trig;
38 size_t len;
39
40 trigger_name[sizeof(trigger_name) - 1] = '\0';
41 strncpy(trigger_name, buf, sizeof(trigger_name) - 1);
42 len = strlen(trigger_name);
43
44 if (len && trigger_name[len - 1] == '\n')
45 trigger_name[len - 1] = '\0';
46
47 if (!strcmp(trigger_name, "none")) {
48 write_lock(&led_cdev->trigger_lock);
49 led_trigger_set(led_cdev, NULL);
50 write_unlock(&led_cdev->trigger_lock);
51 return count;
52 }
53
54 read_lock(&triggers_list_lock);
55 list_for_each_entry(trig, &trigger_list, next_trig) {
56 if (!strcmp(trigger_name, trig->name)) {
57 write_lock(&led_cdev->trigger_lock);
58 led_trigger_set(led_cdev, trig);
59 write_unlock(&led_cdev->trigger_lock);
60
61 read_unlock(&triggers_list_lock);
62 return count;
63 }
64 }
65 read_unlock(&triggers_list_lock);
66
67 return -EINVAL;
68 }
69
70
71 ssize_t led_trigger_show(struct class_device *dev, char *buf)
72 {
73 struct led_classdev *led_cdev = class_get_devdata(dev);
74 struct led_trigger *trig;
75 int len = 0;
76
77 read_lock(&triggers_list_lock);
78 read_lock(&led_cdev->trigger_lock);
79
80 if (!led_cdev->trigger)
81 len += sprintf(buf+len, "[none] ");
82 else
83 len += sprintf(buf+len, "none ");
84
85 list_for_each_entry(trig, &trigger_list, next_trig) {
86 if (led_cdev->trigger && !strcmp(led_cdev->trigger->name,
87 trig->name))
88 len += sprintf(buf+len, "[%s] ", trig->name);
89 else
90 len += sprintf(buf+len, "%s ", trig->name);
91 }
92 read_unlock(&led_cdev->trigger_lock);
93 read_unlock(&triggers_list_lock);
94
95 len += sprintf(len+buf, "\n");
96 return len;
97 }
98
99 void led_trigger_event(struct led_trigger *trigger,
100 enum led_brightness brightness)
101 {
102 struct list_head *entry;
103
104 if (!trigger)
105 return;
106
107 read_lock(&trigger->leddev_list_lock);
108 list_for_each(entry, &trigger->led_cdevs) {
109 struct led_classdev *led_cdev;
110
111 led_cdev = list_entry(entry, struct led_classdev, trig_list);
112 led_set_brightness(led_cdev, brightness);
113 }
114 read_unlock(&trigger->leddev_list_lock);
115 }
116
117 /* Caller must ensure led_cdev->trigger_lock held */
118 void led_trigger_set(struct led_classdev *led_cdev, struct led_trigger *trigger)
119 {
120 unsigned long flags;
121
122 /* Remove any existing trigger */
123 if (led_cdev->trigger) {
124 write_lock_irqsave(&led_cdev->trigger->leddev_list_lock, flags);
125 list_del(&led_cdev->trig_list);
126 write_unlock_irqrestore(&led_cdev->trigger->leddev_list_lock, flags);
127 if (led_cdev->trigger->deactivate)
128 led_cdev->trigger->deactivate(led_cdev);
129 }
130 if (trigger) {
131 write_lock_irqsave(&trigger->leddev_list_lock, flags);
132 list_add_tail(&led_cdev->trig_list, &trigger->led_cdevs);
133 write_unlock_irqrestore(&trigger->leddev_list_lock, flags);
134 if (trigger->activate)
135 trigger->activate(led_cdev);
136 }
137 led_cdev->trigger = trigger;
138 }
139
140 void led_trigger_set_default(struct led_classdev *led_cdev)
141 {
142 struct led_trigger *trig;
143
144 if (!led_cdev->default_trigger)
145 return;
146
147 read_lock(&triggers_list_lock);
148 write_lock(&led_cdev->trigger_lock);
149 list_for_each_entry(trig, &trigger_list, next_trig) {
150 if (!strcmp(led_cdev->default_trigger, trig->name))
151 led_trigger_set(led_cdev, trig);
152 }
153 write_unlock(&led_cdev->trigger_lock);
154 read_unlock(&triggers_list_lock);
155 }
156
157 int led_trigger_register(struct led_trigger *trigger)
158 {
159 struct led_classdev *led_cdev;
160
161 rwlock_init(&trigger->leddev_list_lock);
162 INIT_LIST_HEAD(&trigger->led_cdevs);
163
164 /* Add to the list of led triggers */
165 write_lock(&triggers_list_lock);
166 list_add_tail(&trigger->next_trig, &trigger_list);
167 write_unlock(&triggers_list_lock);
168
169 /* Register with any LEDs that have this as a default trigger */
170 read_lock(&leds_list_lock);
171 list_for_each_entry(led_cdev, &leds_list, node) {
172 write_lock(&led_cdev->trigger_lock);
173 if (!led_cdev->trigger && led_cdev->default_trigger &&
174 !strcmp(led_cdev->default_trigger, trigger->name))
175 led_trigger_set(led_cdev, trigger);
176 write_unlock(&led_cdev->trigger_lock);
177 }
178 read_unlock(&leds_list_lock);
179
180 return 0;
181 }
182
183 void led_trigger_register_simple(const char *name, struct led_trigger **tp)
184 {
185 struct led_trigger *trigger;
186
187 trigger = kzalloc(sizeof(struct led_trigger), GFP_KERNEL);
188
189 if (trigger) {
190 trigger->name = name;
191 led_trigger_register(trigger);
192 }
193 *tp = trigger;
194 }
195
196 void led_trigger_unregister(struct led_trigger *trigger)
197 {
198 struct led_classdev *led_cdev;
199
200 /* Remove from the list of led triggers */
201 write_lock(&triggers_list_lock);
202 list_del(&trigger->next_trig);
203 write_unlock(&triggers_list_lock);
204
205 /* Remove anyone actively using this trigger */
206 read_lock(&leds_list_lock);
207 list_for_each_entry(led_cdev, &leds_list, node) {
208 write_lock(&led_cdev->trigger_lock);
209 if (led_cdev->trigger == trigger)
210 led_trigger_set(led_cdev, NULL);
211 write_unlock(&led_cdev->trigger_lock);
212 }
213 read_unlock(&leds_list_lock);
214 }
215
216 void led_trigger_unregister_simple(struct led_trigger *trigger)
217 {
218 led_trigger_unregister(trigger);
219 kfree(trigger);
220 }
221
222 /* Used by LED Class */
223 EXPORT_SYMBOL_GPL(led_trigger_set);
224 EXPORT_SYMBOL_GPL(led_trigger_set_default);
225 EXPORT_SYMBOL_GPL(led_trigger_show);
226 EXPORT_SYMBOL_GPL(led_trigger_store);
227
228 /* LED Trigger Interface */
229 EXPORT_SYMBOL_GPL(led_trigger_register);
230 EXPORT_SYMBOL_GPL(led_trigger_unregister);
231
232 /* Simple LED Tigger Interface */
233 EXPORT_SYMBOL_GPL(led_trigger_register_simple);
234 EXPORT_SYMBOL_GPL(led_trigger_unregister_simple);
235 EXPORT_SYMBOL_GPL(led_trigger_event);
236
237 MODULE_AUTHOR("Richard Purdie");
238 MODULE_LICENSE("GPL");
239 MODULE_DESCRIPTION("LED Triggers Core");
240
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