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[karo-tx-linux.git] / drivers / leds / led-class.c
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
24 static struct class *leds_class;
25
26 static 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
32 static 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
43 static 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
61 static 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
69 static 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
78 static 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 static void set_brightness_delayed(struct work_struct *ws)
128 {
129         struct led_classdev *led_cdev =
130                 container_of(ws, struct led_classdev, set_brightness_work);
131
132         led_stop_software_blink(led_cdev);
133
134         __led_set_brightness(led_cdev, led_cdev->delayed_set_value);
135 }
136
137 /**
138  * led_classdev_suspend - suspend an led_classdev.
139  * @led_cdev: the led_classdev to suspend.
140  */
141 void led_classdev_suspend(struct led_classdev *led_cdev)
142 {
143         led_cdev->flags |= LED_SUSPENDED;
144         led_cdev->brightness_set(led_cdev, 0);
145 }
146 EXPORT_SYMBOL_GPL(led_classdev_suspend);
147
148 /**
149  * led_classdev_resume - resume an led_classdev.
150  * @led_cdev: the led_classdev to resume.
151  */
152 void led_classdev_resume(struct led_classdev *led_cdev)
153 {
154         led_cdev->brightness_set(led_cdev, led_cdev->brightness);
155         led_cdev->flags &= ~LED_SUSPENDED;
156 }
157 EXPORT_SYMBOL_GPL(led_classdev_resume);
158
159 static int led_suspend(struct device *dev, pm_message_t state)
160 {
161         struct led_classdev *led_cdev = dev_get_drvdata(dev);
162
163         if (led_cdev->flags & LED_CORE_SUSPENDRESUME)
164                 led_classdev_suspend(led_cdev);
165
166         return 0;
167 }
168
169 static int led_resume(struct device *dev)
170 {
171         struct led_classdev *led_cdev = dev_get_drvdata(dev);
172
173         if (led_cdev->flags & LED_CORE_SUSPENDRESUME)
174                 led_classdev_resume(led_cdev);
175
176         return 0;
177 }
178
179 /**
180  * led_classdev_register - register a new object of led_classdev class.
181  * @parent: The device to register.
182  * @led_cdev: the led_classdev structure for this device.
183  */
184 int led_classdev_register(struct device *parent, struct led_classdev *led_cdev)
185 {
186         led_cdev->dev = device_create(leds_class, parent, 0, led_cdev,
187                                       "%s", led_cdev->name);
188         if (IS_ERR(led_cdev->dev))
189                 return PTR_ERR(led_cdev->dev);
190
191 #ifdef CONFIG_LEDS_TRIGGERS
192         init_rwsem(&led_cdev->trigger_lock);
193 #endif
194         /* add to the list of leds */
195         down_write(&leds_list_lock);
196         list_add_tail(&led_cdev->node, &leds_list);
197         up_write(&leds_list_lock);
198
199         if (!led_cdev->max_brightness)
200                 led_cdev->max_brightness = LED_FULL;
201
202         led_update_brightness(led_cdev);
203
204         INIT_WORK(&led_cdev->set_brightness_work, set_brightness_delayed);
205
206         init_timer(&led_cdev->blink_timer);
207         led_cdev->blink_timer.function = led_timer_function;
208         led_cdev->blink_timer.data = (unsigned long)led_cdev;
209
210 #ifdef CONFIG_LEDS_TRIGGERS
211         led_trigger_set_default(led_cdev);
212 #endif
213
214         dev_dbg(parent, "Registered led device: %s\n",
215                         led_cdev->name);
216
217         return 0;
218 }
219 EXPORT_SYMBOL_GPL(led_classdev_register);
220
221 /**
222  * led_classdev_unregister - unregisters a object of led_properties class.
223  * @led_cdev: the led device to unregister
224  *
225  * Unregisters a previously registered via led_classdev_register object.
226  */
227 void led_classdev_unregister(struct led_classdev *led_cdev)
228 {
229 #ifdef CONFIG_LEDS_TRIGGERS
230         down_write(&led_cdev->trigger_lock);
231         if (led_cdev->trigger)
232                 led_trigger_set(led_cdev, NULL);
233         up_write(&led_cdev->trigger_lock);
234 #endif
235
236         cancel_work_sync(&led_cdev->set_brightness_work);
237
238         /* Stop blinking */
239         led_stop_software_blink(led_cdev);
240         led_set_brightness(led_cdev, LED_OFF);
241
242         device_unregister(led_cdev->dev);
243
244         down_write(&leds_list_lock);
245         list_del(&led_cdev->node);
246         up_write(&leds_list_lock);
247 }
248 EXPORT_SYMBOL_GPL(led_classdev_unregister);
249
250 static int __init leds_init(void)
251 {
252         leds_class = class_create(THIS_MODULE, "leds");
253         if (IS_ERR(leds_class))
254                 return PTR_ERR(leds_class);
255         leds_class->suspend = led_suspend;
256         leds_class->resume = led_resume;
257         leds_class->dev_attrs = led_class_attrs;
258         return 0;
259 }
260
261 static void __exit leds_exit(void)
262 {
263         class_destroy(leds_class);
264 }
265
266 subsys_initcall(leds_init);
267 module_exit(leds_exit);
268
269 MODULE_AUTHOR("John Lenz, Richard Purdie");
270 MODULE_LICENSE("GPL");
271 MODULE_DESCRIPTION("LED Class Interface");