Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
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/timer.h>
19#include <linux/err.h>
20#include <linux/ctype.h>
21#include <linux/leds.h>
22#include "leds.h"
23
24static struct class *leds_class;
25
26static void led_update_brightness(struct led_classdev *led_cdev)
27{
28 if (led_cdev->brightness_get)
29 led_cdev->brightness = led_cdev->brightness_get(led_cdev);
30}
31
32static ssize_t led_brightness_show(struct device *dev,
33 struct device_attribute *attr, char *buf)
34{
35 struct led_classdev *led_cdev = dev_get_drvdata(dev);
36
37 /* no lock needed for this */
38 led_update_brightness(led_cdev);
39
40 return sprintf(buf, "%u\n", led_cdev->brightness);
41}
42
43static ssize_t led_brightness_store(struct device *dev,
44 struct device_attribute *attr, const char *buf, size_t size)
45{
46 struct led_classdev *led_cdev = dev_get_drvdata(dev);
47 ssize_t ret = -EINVAL;
48 char *after;
49 unsigned long state = simple_strtoul(buf, &after, 10);
50 size_t count = after - buf;
51
52 if (isspace(*after))
53 count++;
54
55 if (count == size) {
56 ret = count;
57
58 if (state == LED_OFF)
59 led_trigger_remove(led_cdev);
60 led_set_brightness(led_cdev, state);
61 }
62
63 return ret;
64}
65
66static ssize_t led_max_brightness_show(struct device *dev,
67 struct device_attribute *attr, char *buf)
68{
69 struct led_classdev *led_cdev = dev_get_drvdata(dev);
70
71 return sprintf(buf, "%u\n", led_cdev->max_brightness);
72}
73
74static struct device_attribute led_class_attrs[] = {
75 __ATTR(brightness, 0644, led_brightness_show, led_brightness_store),
76 __ATTR(max_brightness, 0444, led_max_brightness_show, NULL),
77#ifdef CONFIG_LEDS_TRIGGERS
78 __ATTR(trigger, 0644, led_trigger_show, led_trigger_store),
79#endif
80 __ATTR_NULL,
81};
82
83static void led_timer_function(unsigned long data)
84{
85 struct led_classdev *led_cdev = (void *)data;
86 unsigned long brightness;
87 unsigned long delay;
88
89 if (!led_cdev->blink_delay_on || !led_cdev->blink_delay_off) {
90 led_set_brightness(led_cdev, LED_OFF);
91 return;
92 }
93
94 brightness = led_get_brightness(led_cdev);
95 if (!brightness) {
96 /* Time to switch the LED on. */
97 brightness = led_cdev->blink_brightness;
98 delay = led_cdev->blink_delay_on;
99 } else {
100 /* Store the current brightness value to be able
101 * to restore it when the delay_off period is over.
102 */
103 led_cdev->blink_brightness = brightness;
104 brightness = LED_OFF;
105 delay = led_cdev->blink_delay_off;
106 }
107
108 led_set_brightness(led_cdev, brightness);
109
110 mod_timer(&led_cdev->blink_timer, jiffies + msecs_to_jiffies(delay));
111}
112
113/**
114 * led_classdev_suspend - suspend an led_classdev.
115 * @led_cdev: the led_classdev to suspend.
116 */
117void led_classdev_suspend(struct led_classdev *led_cdev)
118{
119 led_cdev->flags |= LED_SUSPENDED;
120 led_cdev->brightness_set(led_cdev, 0);
121}
122EXPORT_SYMBOL_GPL(led_classdev_suspend);
123
124/**
125 * led_classdev_resume - resume an led_classdev.
126 * @led_cdev: the led_classdev to resume.
127 */
128void led_classdev_resume(struct led_classdev *led_cdev)
129{
130 led_cdev->brightness_set(led_cdev, led_cdev->brightness);
131 led_cdev->flags &= ~LED_SUSPENDED;
132}
133EXPORT_SYMBOL_GPL(led_classdev_resume);
134
135static int led_suspend(struct device *dev, pm_message_t state)
136{
137 struct led_classdev *led_cdev = dev_get_drvdata(dev);
138
139 if (led_cdev->flags & LED_CORE_SUSPENDRESUME)
140 led_classdev_suspend(led_cdev);
141
142 return 0;
143}
144
145static int led_resume(struct device *dev)
146{
147 struct led_classdev *led_cdev = dev_get_drvdata(dev);
148
149 if (led_cdev->flags & LED_CORE_SUSPENDRESUME)
150 led_classdev_resume(led_cdev);
151
152 return 0;
153}
154
155/**
156 * led_classdev_register - register a new object of led_classdev class.
157 * @parent: The device to register.
158 * @led_cdev: the led_classdev structure for this device.
159 */
160int led_classdev_register(struct device *parent, struct led_classdev *led_cdev)
161{
162 led_cdev->dev = device_create(leds_class, parent, 0, led_cdev,
163 "%s", led_cdev->name);
164 if (IS_ERR(led_cdev->dev))
165 return PTR_ERR(led_cdev->dev);
166
167#ifdef CONFIG_LEDS_TRIGGERS
168 init_rwsem(&led_cdev->trigger_lock);
169#endif
170 /* add to the list of leds */
171 down_write(&leds_list_lock);
172 list_add_tail(&led_cdev->node, &leds_list);
173 up_write(&leds_list_lock);
174
175 if (!led_cdev->max_brightness)
176 led_cdev->max_brightness = LED_FULL;
177
178 led_update_brightness(led_cdev);
179
180 init_timer(&led_cdev->blink_timer);
181 led_cdev->blink_timer.function = led_timer_function;
182 led_cdev->blink_timer.data = (unsigned long)led_cdev;
183
184#ifdef CONFIG_LEDS_TRIGGERS
185 led_trigger_set_default(led_cdev);
186#endif
187
188 printk(KERN_DEBUG "Registered led device: %s\n",
189 led_cdev->name);
190
191 return 0;
192}
193EXPORT_SYMBOL_GPL(led_classdev_register);
194
195/**
196 * led_classdev_unregister - unregisters a object of led_properties class.
197 * @led_cdev: the led device to unregister
198 *
199 * Unregisters a previously registered via led_classdev_register object.
200 */
201void led_classdev_unregister(struct led_classdev *led_cdev)
202{
203#ifdef CONFIG_LEDS_TRIGGERS
204 down_write(&led_cdev->trigger_lock);
205 if (led_cdev->trigger)
206 led_trigger_set(led_cdev, NULL);
207 up_write(&led_cdev->trigger_lock);
208#endif
209
210 /* Stop blinking */
211 led_brightness_set(led_cdev, LED_OFF);
212
213 device_unregister(led_cdev->dev);
214
215 down_write(&leds_list_lock);
216 list_del(&led_cdev->node);
217 up_write(&leds_list_lock);
218}
219EXPORT_SYMBOL_GPL(led_classdev_unregister);
220
221static int __init leds_init(void)
222{
223 leds_class = class_create(THIS_MODULE, "leds");
224 if (IS_ERR(leds_class))
225 return PTR_ERR(leds_class);
226 leds_class->suspend = led_suspend;
227 leds_class->resume = led_resume;
228 leds_class->dev_attrs = led_class_attrs;
229 return 0;
230}
231
232static void __exit leds_exit(void)
233{
234 class_destroy(leds_class);
235}
236
237subsys_initcall(leds_init);
238module_exit(leds_exit);
239
240MODULE_AUTHOR("John Lenz, Richard Purdie");
241MODULE_LICENSE("GPL");
242MODULE_DESCRIPTION("LED Class Interface");