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 unsigned long state;
48 ssize_t ret = -EINVAL;
49
50 ret = kstrtoul(buf, 10, &state);
51 if (ret)
52 return ret;
53
54 if (state == LED_OFF)
55 led_trigger_remove(led_cdev);
56 __led_set_brightness(led_cdev, state);
57
58 return size;
59}
60
61static ssize_t led_max_brightness_show(struct device *dev,
62 struct device_attribute *attr, char *buf)
63{
64 struct led_classdev *led_cdev = dev_get_drvdata(dev);
65
66 return sprintf(buf, "%u\n", led_cdev->max_brightness);
67}
68
69static struct device_attribute led_class_attrs[] = {
70 __ATTR(brightness, 0644, led_brightness_show, led_brightness_store),
71 __ATTR(max_brightness, 0444, led_max_brightness_show, NULL),
72#ifdef CONFIG_LEDS_TRIGGERS
73 __ATTR(trigger, 0644, led_trigger_show, led_trigger_store),
74#endif
75 __ATTR_NULL,
76};
77
78static void led_timer_function(unsigned long data)
79{
80 struct led_classdev *led_cdev = (void *)data;
81 unsigned long brightness;
82 unsigned long delay;
83
84 if (!led_cdev->blink_delay_on || !led_cdev->blink_delay_off) {
85 __led_set_brightness(led_cdev, LED_OFF);
86 return;
87 }
88
89 if (led_cdev->flags & LED_BLINK_ONESHOT_STOP) {
90 led_cdev->flags &= ~LED_BLINK_ONESHOT_STOP;
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 /* Return in next iteration if led is in one-shot mode and we are in
111 * the final blink state so that the led is toggled each delay_on +
112 * delay_off milliseconds in worst case.
113 */
114 if (led_cdev->flags & LED_BLINK_ONESHOT) {
115 if (led_cdev->flags & LED_BLINK_INVERT) {
116 if (brightness)
117 led_cdev->flags |= LED_BLINK_ONESHOT_STOP;
118 } else {
119 if (!brightness)
120 led_cdev->flags |= LED_BLINK_ONESHOT_STOP;
121 }
122 }
123
124 mod_timer(&led_cdev->blink_timer, jiffies + msecs_to_jiffies(delay));
125}
126
127/**
128 * led_classdev_suspend - suspend an led_classdev.
129 * @led_cdev: the led_classdev to suspend.
130 */
131void led_classdev_suspend(struct led_classdev *led_cdev)
132{
133 led_cdev->flags |= LED_SUSPENDED;
134 led_cdev->brightness_set(led_cdev, 0);
135}
136EXPORT_SYMBOL_GPL(led_classdev_suspend);
137
138/**
139 * led_classdev_resume - resume an led_classdev.
140 * @led_cdev: the led_classdev to resume.
141 */
142void led_classdev_resume(struct led_classdev *led_cdev)
143{
144 led_cdev->brightness_set(led_cdev, led_cdev->brightness);
145 led_cdev->flags &= ~LED_SUSPENDED;
146}
147EXPORT_SYMBOL_GPL(led_classdev_resume);
148
149static int led_suspend(struct device *dev, pm_message_t state)
150{
151 struct led_classdev *led_cdev = dev_get_drvdata(dev);
152
153 if (led_cdev->flags & LED_CORE_SUSPENDRESUME)
154 led_classdev_suspend(led_cdev);
155
156 return 0;
157}
158
159static int led_resume(struct device *dev)
160{
161 struct led_classdev *led_cdev = dev_get_drvdata(dev);
162
163 if (led_cdev->flags & LED_CORE_SUSPENDRESUME)
164 led_classdev_resume(led_cdev);
165
166 return 0;
167}
168
169/**
170 * led_classdev_register - register a new object of led_classdev class.
171 * @parent: The device to register.
172 * @led_cdev: the led_classdev structure for this device.
173 */
174int led_classdev_register(struct device *parent, struct led_classdev *led_cdev)
175{
176 led_cdev->dev = device_create(leds_class, parent, 0, led_cdev,
177 "%s", led_cdev->name);
178 if (IS_ERR(led_cdev->dev))
179 return PTR_ERR(led_cdev->dev);
180
181#ifdef CONFIG_LEDS_TRIGGERS
182 init_rwsem(&led_cdev->trigger_lock);
183#endif
184 /* add to the list of leds */
185 down_write(&leds_list_lock);
186 list_add_tail(&led_cdev->node, &leds_list);
187 up_write(&leds_list_lock);
188
189 if (!led_cdev->max_brightness)
190 led_cdev->max_brightness = LED_FULL;
191
192 led_update_brightness(led_cdev);
193
194 init_timer(&led_cdev->blink_timer);
195 led_cdev->blink_timer.function = led_timer_function;
196 led_cdev->blink_timer.data = (unsigned long)led_cdev;
197
198#ifdef CONFIG_LEDS_TRIGGERS
199 led_trigger_set_default(led_cdev);
200#endif
201
202 printk(KERN_DEBUG "Registered led device: %s\n",
203 led_cdev->name);
204
205 return 0;
206}
207EXPORT_SYMBOL_GPL(led_classdev_register);
208
209/**
210 * led_classdev_unregister - unregisters a object of led_properties class.
211 * @led_cdev: the led device to unregister
212 *
213 * Unregisters a previously registered via led_classdev_register object.
214 */
215void led_classdev_unregister(struct led_classdev *led_cdev)
216{
217#ifdef CONFIG_LEDS_TRIGGERS
218 down_write(&led_cdev->trigger_lock);
219 if (led_cdev->trigger)
220 led_trigger_set(led_cdev, NULL);
221 up_write(&led_cdev->trigger_lock);
222#endif
223
224 /* Stop blinking */
225 led_set_brightness(led_cdev, LED_OFF);
226
227 device_unregister(led_cdev->dev);
228
229 down_write(&leds_list_lock);
230 list_del(&led_cdev->node);
231 up_write(&leds_list_lock);
232}
233EXPORT_SYMBOL_GPL(led_classdev_unregister);
234
235static int __init leds_init(void)
236{
237 leds_class = class_create(THIS_MODULE, "leds");
238 if (IS_ERR(leds_class))
239 return PTR_ERR(leds_class);
240 leds_class->suspend = led_suspend;
241 leds_class->resume = led_resume;
242 leds_class->dev_attrs = led_class_attrs;
243 return 0;
244}
245
246static void __exit leds_exit(void)
247{
248 class_destroy(leds_class);
249}
250
251subsys_initcall(leds_init);
252module_exit(leds_exit);
253
254MODULE_AUTHOR("John Lenz, Richard Purdie");
255MODULE_LICENSE("GPL");
256MODULE_DESCRIPTION("LED Class Interface");