4 * Copyright 2005-2007 Openedhand Ltd.
6 * Author: Richard Purdie <rpurdie@openedhand.com>
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.
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/rwsem.h>
23 #include <linux/leds.h>
27 * Nests outside led_cdev->trigger_lock
29 static DECLARE_RWSEM(triggers_list_lock);
30 static LIST_HEAD(trigger_list);
32 ssize_t led_trigger_store(struct device *dev, struct device_attribute *attr,
33 const char *buf, size_t count)
35 struct led_classdev *led_cdev = dev_get_drvdata(dev);
36 char trigger_name[TRIG_NAME_MAX];
37 struct led_trigger *trig;
40 trigger_name[sizeof(trigger_name) - 1] = '\0';
41 strncpy(trigger_name, buf, sizeof(trigger_name) - 1);
42 len = strlen(trigger_name);
44 if (len && trigger_name[len - 1] == '\n')
45 trigger_name[len - 1] = '\0';
47 if (!strcmp(trigger_name, "none")) {
48 led_trigger_remove(led_cdev);
52 down_read(&triggers_list_lock);
53 list_for_each_entry(trig, &trigger_list, next_trig) {
54 if (!strcmp(trigger_name, trig->name)) {
55 down_write(&led_cdev->trigger_lock);
56 led_trigger_set(led_cdev, trig);
57 up_write(&led_cdev->trigger_lock);
59 up_read(&triggers_list_lock);
63 up_read(&triggers_list_lock);
69 ssize_t led_trigger_show(struct device *dev, struct device_attribute *attr,
72 struct led_classdev *led_cdev = dev_get_drvdata(dev);
73 struct led_trigger *trig;
76 down_read(&triggers_list_lock);
77 down_read(&led_cdev->trigger_lock);
79 if (!led_cdev->trigger)
80 len += sprintf(buf+len, "[none] ");
82 len += sprintf(buf+len, "none ");
84 list_for_each_entry(trig, &trigger_list, next_trig) {
85 if (led_cdev->trigger && !strcmp(led_cdev->trigger->name,
87 len += sprintf(buf+len, "[%s] ", trig->name);
89 len += sprintf(buf+len, "%s ", trig->name);
91 up_read(&led_cdev->trigger_lock);
92 up_read(&triggers_list_lock);
94 len += sprintf(len+buf, "\n");
98 void led_trigger_event(struct led_trigger *trigger,
99 enum led_brightness brightness)
101 struct list_head *entry;
106 read_lock(&trigger->leddev_list_lock);
107 list_for_each(entry, &trigger->led_cdevs) {
108 struct led_classdev *led_cdev;
110 led_cdev = list_entry(entry, struct led_classdev, trig_list);
111 led_set_brightness(led_cdev, brightness);
113 read_unlock(&trigger->leddev_list_lock);
116 /* Caller must ensure led_cdev->trigger_lock held */
117 void led_trigger_set(struct led_classdev *led_cdev, struct led_trigger *trigger)
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 led_set_brightness(led_cdev, LED_OFF);
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);
137 led_cdev->trigger = trigger;
140 void led_trigger_remove(struct led_classdev *led_cdev)
142 down_write(&led_cdev->trigger_lock);
143 led_trigger_set(led_cdev, NULL);
144 up_write(&led_cdev->trigger_lock);
147 void led_trigger_set_default(struct led_classdev *led_cdev)
149 struct led_trigger *trig;
151 if (!led_cdev->default_trigger)
154 down_read(&triggers_list_lock);
155 down_write(&led_cdev->trigger_lock);
156 list_for_each_entry(trig, &trigger_list, next_trig) {
157 if (!strcmp(led_cdev->default_trigger, trig->name))
158 led_trigger_set(led_cdev, trig);
160 up_write(&led_cdev->trigger_lock);
161 up_read(&triggers_list_lock);
164 int led_trigger_register(struct led_trigger *trigger)
166 struct led_classdev *led_cdev;
168 rwlock_init(&trigger->leddev_list_lock);
169 INIT_LIST_HEAD(&trigger->led_cdevs);
171 /* Add to the list of led triggers */
172 down_write(&triggers_list_lock);
173 list_add_tail(&trigger->next_trig, &trigger_list);
174 up_write(&triggers_list_lock);
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);
185 up_read(&leds_list_lock);
190 void led_trigger_register_simple(const char *name, struct led_trigger **tp)
192 struct led_trigger *trigger;
195 trigger = kzalloc(sizeof(struct led_trigger), GFP_KERNEL);
198 trigger->name = name;
199 err = led_trigger_register(trigger);
201 printk(KERN_WARNING "LED trigger %s failed to register"
202 " (%d)\n", name, err);
204 printk(KERN_WARNING "LED trigger %s failed to register"
205 " (no memory)\n", name);
210 void led_trigger_unregister(struct led_trigger *trigger)
212 struct led_classdev *led_cdev;
214 /* Remove from the list of led triggers */
215 down_write(&triggers_list_lock);
216 list_del(&trigger->next_trig);
217 up_write(&triggers_list_lock);
219 /* Remove anyone actively using this trigger */
220 down_read(&leds_list_lock);
221 list_for_each_entry(led_cdev, &leds_list, node) {
222 down_write(&led_cdev->trigger_lock);
223 if (led_cdev->trigger == trigger)
224 led_trigger_set(led_cdev, NULL);
225 up_write(&led_cdev->trigger_lock);
227 up_read(&leds_list_lock);
230 void led_trigger_unregister_simple(struct led_trigger *trigger)
233 led_trigger_unregister(trigger);
237 /* Used by LED Class */
238 EXPORT_SYMBOL_GPL(led_trigger_set);
239 EXPORT_SYMBOL_GPL(led_trigger_remove);
240 EXPORT_SYMBOL_GPL(led_trigger_set_default);
241 EXPORT_SYMBOL_GPL(led_trigger_show);
242 EXPORT_SYMBOL_GPL(led_trigger_store);
244 /* LED Trigger Interface */
245 EXPORT_SYMBOL_GPL(led_trigger_register);
246 EXPORT_SYMBOL_GPL(led_trigger_unregister);
248 /* Simple LED Tigger Interface */
249 EXPORT_SYMBOL_GPL(led_trigger_register_simple);
250 EXPORT_SYMBOL_GPL(led_trigger_unregister_simple);
251 EXPORT_SYMBOL_GPL(led_trigger_event);
253 MODULE_AUTHOR("Richard Purdie");
254 MODULE_LICENSE("GPL");
255 MODULE_DESCRIPTION("LED Triggers Core");