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1/*
2 * LED Triggers Core
3 *
4 * Copyright 2005-2007 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/timer.h>
21#include <linux/rwsem.h>
22#include <linux/leds.h>
23#include <linux/slab.h>
24#include "leds.h"
25
26/*
27 * Nests outside led_cdev->trigger_lock
28 */
29static DECLARE_RWSEM(triggers_list_lock);
30static LIST_HEAD(trigger_list);
31
32 /* Used by LED Class */
33
34ssize_t led_trigger_store(struct device *dev, struct device_attribute *attr,
35 const char *buf, size_t count)
36{
37 struct led_classdev *led_cdev = dev_get_drvdata(dev);
38 char trigger_name[TRIG_NAME_MAX];
39 struct led_trigger *trig;
40 size_t len;
41
42 trigger_name[sizeof(trigger_name) - 1] = '\0';
43 strncpy(trigger_name, buf, sizeof(trigger_name) - 1);
44 len = strlen(trigger_name);
45
46 if (len && trigger_name[len - 1] == '\n')
47 trigger_name[len - 1] = '\0';
48
49 if (!strcmp(trigger_name, "none")) {
50 led_trigger_remove(led_cdev);
51 return count;
52 }
53
54 down_read(&triggers_list_lock);
55 list_for_each_entry(trig, &trigger_list, next_trig) {
56 if (!strcmp(trigger_name, trig->name)) {
57 down_write(&led_cdev->trigger_lock);
58 led_trigger_set(led_cdev, trig);
59 up_write(&led_cdev->trigger_lock);
60
61 up_read(&triggers_list_lock);
62 return count;
63 }
64 }
65 up_read(&triggers_list_lock);
66
67 return -EINVAL;
68}
69EXPORT_SYMBOL_GPL(led_trigger_store);
70
71ssize_t led_trigger_show(struct device *dev, struct device_attribute *attr,
72 char *buf)
73{
74 struct led_classdev *led_cdev = dev_get_drvdata(dev);
75 struct led_trigger *trig;
76 int len = 0;
77
78 down_read(&triggers_list_lock);
79 down_read(&led_cdev->trigger_lock);
80
81 if (!led_cdev->trigger)
82 len += sprintf(buf+len, "[none] ");
83 else
84 len += sprintf(buf+len, "none ");
85
86 list_for_each_entry(trig, &trigger_list, next_trig) {
87 if (led_cdev->trigger && !strcmp(led_cdev->trigger->name,
88 trig->name))
89 len += sprintf(buf+len, "[%s] ", trig->name);
90 else
91 len += sprintf(buf+len, "%s ", trig->name);
92 }
93 up_read(&led_cdev->trigger_lock);
94 up_read(&triggers_list_lock);
95
96 len += sprintf(len+buf, "\n");
97 return len;
98}
99EXPORT_SYMBOL_GPL(led_trigger_show);
100
101/* Caller must ensure led_cdev->trigger_lock held */
102void led_trigger_set(struct led_classdev *led_cdev, struct led_trigger *trigger)
103{
104 unsigned long flags;
105
106 /* Remove any existing trigger */
107 if (led_cdev->trigger) {
108 write_lock_irqsave(&led_cdev->trigger->leddev_list_lock, flags);
109 list_del(&led_cdev->trig_list);
110 write_unlock_irqrestore(&led_cdev->trigger->leddev_list_lock,
111 flags);
112 if (led_cdev->trigger->deactivate)
113 led_cdev->trigger->deactivate(led_cdev);
114 led_cdev->trigger = NULL;
115 led_brightness_set(led_cdev, LED_OFF);
116 }
117 if (trigger) {
118 write_lock_irqsave(&trigger->leddev_list_lock, flags);
119 list_add_tail(&led_cdev->trig_list, &trigger->led_cdevs);
120 write_unlock_irqrestore(&trigger->leddev_list_lock, flags);
121 led_cdev->trigger = trigger;
122 if (trigger->activate)
123 trigger->activate(led_cdev);
124 }
125}
126EXPORT_SYMBOL_GPL(led_trigger_set);
127
128void led_trigger_remove(struct led_classdev *led_cdev)
129{
130 down_write(&led_cdev->trigger_lock);
131 led_trigger_set(led_cdev, NULL);
132 up_write(&led_cdev->trigger_lock);
133}
134EXPORT_SYMBOL_GPL(led_trigger_remove);
135
136void led_trigger_set_default(struct led_classdev *led_cdev)
137{
138 struct led_trigger *trig;
139
140 if (!led_cdev->default_trigger)
141 return;
142
143 down_read(&triggers_list_lock);
144 down_write(&led_cdev->trigger_lock);
145 list_for_each_entry(trig, &trigger_list, next_trig) {
146 if (!strcmp(led_cdev->default_trigger, trig->name))
147 led_trigger_set(led_cdev, trig);
148 }
149 up_write(&led_cdev->trigger_lock);
150 up_read(&triggers_list_lock);
151}
152EXPORT_SYMBOL_GPL(led_trigger_set_default);
153
154/* LED Trigger Interface */
155
156int led_trigger_register(struct led_trigger *trigger)
157{
158 struct led_classdev *led_cdev;
159 struct led_trigger *trig;
160
161 rwlock_init(&trigger->leddev_list_lock);
162 INIT_LIST_HEAD(&trigger->led_cdevs);
163
164 down_write(&triggers_list_lock);
165 /* Make sure the trigger's name isn't already in use */
166 list_for_each_entry(trig, &trigger_list, next_trig) {
167 if (!strcmp(trig->name, trigger->name)) {
168 up_write(&triggers_list_lock);
169 return -EEXIST;
170 }
171 }
172 /* Add to the list of led triggers */
173 list_add_tail(&trigger->next_trig, &trigger_list);
174 up_write(&triggers_list_lock);
175
176 /* Register with any LEDs that have this as a default trigger */
177 down_read(&leds_list_lock);
178 list_for_each_entry(led_cdev, &leds_list, node) {
179 down_write(&led_cdev->trigger_lock);
180 if (!led_cdev->trigger && led_cdev->default_trigger &&
181 !strcmp(led_cdev->default_trigger, trigger->name))
182 led_trigger_set(led_cdev, trigger);
183 up_write(&led_cdev->trigger_lock);
184 }
185 up_read(&leds_list_lock);
186
187 return 0;
188}
189EXPORT_SYMBOL_GPL(led_trigger_register);
190
191void led_trigger_unregister(struct led_trigger *trigger)
192{
193 struct led_classdev *led_cdev;
194
195 /* Remove from the list of led triggers */
196 down_write(&triggers_list_lock);
197 list_del(&trigger->next_trig);
198 up_write(&triggers_list_lock);
199
200 /* Remove anyone actively using this trigger */
201 down_read(&leds_list_lock);
202 list_for_each_entry(led_cdev, &leds_list, node) {
203 down_write(&led_cdev->trigger_lock);
204 if (led_cdev->trigger == trigger)
205 led_trigger_set(led_cdev, NULL);
206 up_write(&led_cdev->trigger_lock);
207 }
208 up_read(&leds_list_lock);
209}
210EXPORT_SYMBOL_GPL(led_trigger_unregister);
211
212/* Simple LED Tigger Interface */
213
214void led_trigger_event(struct led_trigger *trigger,
215 enum led_brightness brightness)
216{
217 struct list_head *entry;
218
219 if (!trigger)
220 return;
221
222 read_lock(&trigger->leddev_list_lock);
223 list_for_each(entry, &trigger->led_cdevs) {
224 struct led_classdev *led_cdev;
225
226 led_cdev = list_entry(entry, struct led_classdev, trig_list);
227 led_set_brightness(led_cdev, brightness);
228 }
229 read_unlock(&trigger->leddev_list_lock);
230}
231EXPORT_SYMBOL_GPL(led_trigger_event);
232
233void led_trigger_blink(struct led_trigger *trigger,
234 unsigned long *delay_on,
235 unsigned long *delay_off)
236{
237 struct list_head *entry;
238
239 if (!trigger)
240 return;
241
242 read_lock(&trigger->leddev_list_lock);
243 list_for_each(entry, &trigger->led_cdevs) {
244 struct led_classdev *led_cdev;
245
246 led_cdev = list_entry(entry, struct led_classdev, trig_list);
247 led_blink_set(led_cdev, delay_on, delay_off);
248 }
249 read_unlock(&trigger->leddev_list_lock);
250}
251EXPORT_SYMBOL_GPL(led_trigger_blink);
252
253void led_trigger_register_simple(const char *name, struct led_trigger **tp)
254{
255 struct led_trigger *trigger;
256 int err;
257
258 trigger = kzalloc(sizeof(struct led_trigger), GFP_KERNEL);
259
260 if (trigger) {
261 trigger->name = name;
262 err = led_trigger_register(trigger);
263 if (err < 0) {
264 kfree(trigger);
265 trigger = NULL;
266 printk(KERN_WARNING "LED trigger %s failed to register"
267 " (%d)\n", name, err);
268 }
269 } else
270 printk(KERN_WARNING "LED trigger %s failed to register"
271 " (no memory)\n", name);
272
273 *tp = trigger;
274}
275EXPORT_SYMBOL_GPL(led_trigger_register_simple);
276
277void led_trigger_unregister_simple(struct led_trigger *trigger)
278{
279 if (trigger)
280 led_trigger_unregister(trigger);
281 kfree(trigger);
282}
283EXPORT_SYMBOL_GPL(led_trigger_unregister_simple);
284
285MODULE_AUTHOR("Richard Purdie");
286MODULE_LICENSE("GPL");
287MODULE_DESCRIPTION("LED Triggers Core");