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[~shefty/rdma-dev.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/sysdev.h>
19 #include <linux/timer.h>
20 #include <linux/err.h>
21 #include <linux/ctype.h>
22 #include <linux/leds.h>
23 #include "leds.h"
24
25 static struct class *leds_class;
26
27 static void led_update_brightness(struct led_classdev *led_cdev)
28 {
29         if (led_cdev->brightness_get)
30                 led_cdev->brightness = led_cdev->brightness_get(led_cdev);
31 }
32
33 static ssize_t led_brightness_show(struct device *dev, 
34                 struct device_attribute *attr, char *buf)
35 {
36         struct led_classdev *led_cdev = dev_get_drvdata(dev);
37
38         /* no lock needed for this */
39         led_update_brightness(led_cdev);
40
41         return sprintf(buf, "%u\n", led_cdev->brightness);
42 }
43
44 static ssize_t led_brightness_store(struct device *dev,
45                 struct device_attribute *attr, const char *buf, size_t size)
46 {
47         struct led_classdev *led_cdev = dev_get_drvdata(dev);
48         ssize_t ret = -EINVAL;
49         char *after;
50         unsigned long state = simple_strtoul(buf, &after, 10);
51         size_t count = after - buf;
52
53         if (isspace(*after))
54                 count++;
55
56         if (count == size) {
57                 ret = count;
58
59                 if (state == LED_OFF)
60                         led_trigger_remove(led_cdev);
61                 led_set_brightness(led_cdev, state);
62         }
63
64         return ret;
65 }
66
67 static ssize_t led_max_brightness_show(struct device *dev,
68                 struct device_attribute *attr, char *buf)
69 {
70         struct led_classdev *led_cdev = dev_get_drvdata(dev);
71
72         return sprintf(buf, "%u\n", led_cdev->max_brightness);
73 }
74
75 static struct device_attribute led_class_attrs[] = {
76         __ATTR(brightness, 0644, led_brightness_show, led_brightness_store),
77         __ATTR(max_brightness, 0444, led_max_brightness_show, NULL),
78 #ifdef CONFIG_LEDS_TRIGGERS
79         __ATTR(trigger, 0644, led_trigger_show, led_trigger_store),
80 #endif
81         __ATTR_NULL,
82 };
83
84 static void led_timer_function(unsigned long data)
85 {
86         struct led_classdev *led_cdev = (void *)data;
87         unsigned long brightness;
88         unsigned long delay;
89
90         if (!led_cdev->blink_delay_on || !led_cdev->blink_delay_off) {
91                 led_set_brightness(led_cdev, LED_OFF);
92                 return;
93         }
94
95         brightness = led_get_brightness(led_cdev);
96         if (!brightness) {
97                 /* Time to switch the LED on. */
98                 brightness = led_cdev->blink_brightness;
99                 delay = led_cdev->blink_delay_on;
100         } else {
101                 /* Store the current brightness value to be able
102                  * to restore it when the delay_off period is over.
103                  */
104                 led_cdev->blink_brightness = brightness;
105                 brightness = LED_OFF;
106                 delay = led_cdev->blink_delay_off;
107         }
108
109         led_set_brightness(led_cdev, brightness);
110
111         mod_timer(&led_cdev->blink_timer, jiffies + msecs_to_jiffies(delay));
112 }
113
114 static void led_stop_software_blink(struct led_classdev *led_cdev)
115 {
116         /* deactivate previous settings */
117         del_timer_sync(&led_cdev->blink_timer);
118         led_cdev->blink_delay_on = 0;
119         led_cdev->blink_delay_off = 0;
120 }
121
122 static void led_set_software_blink(struct led_classdev *led_cdev,
123                                    unsigned long delay_on,
124                                    unsigned long delay_off)
125 {
126         int current_brightness;
127
128         current_brightness = led_get_brightness(led_cdev);
129         if (current_brightness)
130                 led_cdev->blink_brightness = current_brightness;
131         if (!led_cdev->blink_brightness)
132                 led_cdev->blink_brightness = led_cdev->max_brightness;
133
134         if (led_get_trigger_data(led_cdev) &&
135             delay_on == led_cdev->blink_delay_on &&
136             delay_off == led_cdev->blink_delay_off)
137                 return;
138
139         led_stop_software_blink(led_cdev);
140
141         led_cdev->blink_delay_on = delay_on;
142         led_cdev->blink_delay_off = delay_off;
143
144         /* never on - don't blink */
145         if (!delay_on)
146                 return;
147
148         /* never off - just set to brightness */
149         if (!delay_off) {
150                 led_set_brightness(led_cdev, led_cdev->blink_brightness);
151                 return;
152         }
153
154         mod_timer(&led_cdev->blink_timer, jiffies + 1);
155 }
156
157
158 /**
159  * led_classdev_suspend - suspend an led_classdev.
160  * @led_cdev: the led_classdev to suspend.
161  */
162 void led_classdev_suspend(struct led_classdev *led_cdev)
163 {
164         led_cdev->flags |= LED_SUSPENDED;
165         led_cdev->brightness_set(led_cdev, 0);
166 }
167 EXPORT_SYMBOL_GPL(led_classdev_suspend);
168
169 /**
170  * led_classdev_resume - resume an led_classdev.
171  * @led_cdev: the led_classdev to resume.
172  */
173 void led_classdev_resume(struct led_classdev *led_cdev)
174 {
175         led_cdev->brightness_set(led_cdev, led_cdev->brightness);
176         led_cdev->flags &= ~LED_SUSPENDED;
177 }
178 EXPORT_SYMBOL_GPL(led_classdev_resume);
179
180 static int led_suspend(struct device *dev, pm_message_t state)
181 {
182         struct led_classdev *led_cdev = dev_get_drvdata(dev);
183
184         if (led_cdev->flags & LED_CORE_SUSPENDRESUME)
185                 led_classdev_suspend(led_cdev);
186
187         return 0;
188 }
189
190 static int led_resume(struct device *dev)
191 {
192         struct led_classdev *led_cdev = dev_get_drvdata(dev);
193
194         if (led_cdev->flags & LED_CORE_SUSPENDRESUME)
195                 led_classdev_resume(led_cdev);
196
197         return 0;
198 }
199
200 /**
201  * led_classdev_register - register a new object of led_classdev class.
202  * @parent: The device to register.
203  * @led_cdev: the led_classdev structure for this device.
204  */
205 int led_classdev_register(struct device *parent, struct led_classdev *led_cdev)
206 {
207         led_cdev->dev = device_create(leds_class, parent, 0, led_cdev,
208                                       "%s", led_cdev->name);
209         if (IS_ERR(led_cdev->dev))
210                 return PTR_ERR(led_cdev->dev);
211
212 #ifdef CONFIG_LEDS_TRIGGERS
213         init_rwsem(&led_cdev->trigger_lock);
214 #endif
215         /* add to the list of leds */
216         down_write(&leds_list_lock);
217         list_add_tail(&led_cdev->node, &leds_list);
218         up_write(&leds_list_lock);
219
220         if (!led_cdev->max_brightness)
221                 led_cdev->max_brightness = LED_FULL;
222
223         led_update_brightness(led_cdev);
224
225         init_timer(&led_cdev->blink_timer);
226         led_cdev->blink_timer.function = led_timer_function;
227         led_cdev->blink_timer.data = (unsigned long)led_cdev;
228
229 #ifdef CONFIG_LEDS_TRIGGERS
230         led_trigger_set_default(led_cdev);
231 #endif
232
233         printk(KERN_DEBUG "Registered led device: %s\n",
234                         led_cdev->name);
235
236         return 0;
237 }
238 EXPORT_SYMBOL_GPL(led_classdev_register);
239
240 /**
241  * led_classdev_unregister - unregisters a object of led_properties class.
242  * @led_cdev: the led device to unregister
243  *
244  * Unregisters a previously registered via led_classdev_register object.
245  */
246 void led_classdev_unregister(struct led_classdev *led_cdev)
247 {
248 #ifdef CONFIG_LEDS_TRIGGERS
249         down_write(&led_cdev->trigger_lock);
250         if (led_cdev->trigger)
251                 led_trigger_set(led_cdev, NULL);
252         up_write(&led_cdev->trigger_lock);
253 #endif
254
255         /* Stop blinking */
256         led_brightness_set(led_cdev, LED_OFF);
257
258         device_unregister(led_cdev->dev);
259
260         down_write(&leds_list_lock);
261         list_del(&led_cdev->node);
262         up_write(&leds_list_lock);
263 }
264 EXPORT_SYMBOL_GPL(led_classdev_unregister);
265
266 void led_blink_set(struct led_classdev *led_cdev,
267                    unsigned long *delay_on,
268                    unsigned long *delay_off)
269 {
270         del_timer_sync(&led_cdev->blink_timer);
271
272         if (led_cdev->blink_set &&
273             !led_cdev->blink_set(led_cdev, delay_on, delay_off)) {
274                 led_cdev->blink_delay_on = *delay_on;
275                 led_cdev->blink_delay_off = *delay_off;
276                 return;
277         }
278
279         /* blink with 1 Hz as default if nothing specified */
280         if (!*delay_on && !*delay_off)
281                 *delay_on = *delay_off = 500;
282
283         led_set_software_blink(led_cdev, *delay_on, *delay_off);
284 }
285 EXPORT_SYMBOL(led_blink_set);
286
287 void led_brightness_set(struct led_classdev *led_cdev,
288                         enum led_brightness brightness)
289 {
290         led_stop_software_blink(led_cdev);
291         led_cdev->brightness_set(led_cdev, brightness);
292 }
293 EXPORT_SYMBOL(led_brightness_set);
294
295 static int __init leds_init(void)
296 {
297         leds_class = class_create(THIS_MODULE, "leds");
298         if (IS_ERR(leds_class))
299                 return PTR_ERR(leds_class);
300         leds_class->suspend = led_suspend;
301         leds_class->resume = led_resume;
302         leds_class->dev_attrs = led_class_attrs;
303         return 0;
304 }
305
306 static void __exit leds_exit(void)
307 {
308         class_destroy(leds_class);
309 }
310
311 subsys_initcall(leds_init);
312 module_exit(leds_exit);
313
314 MODULE_AUTHOR("John Lenz, Richard Purdie");
315 MODULE_LICENSE("GPL");
316 MODULE_DESCRIPTION("LED Class Interface");