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
led_update_brightness(struct led_classdev * led_cdev)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
led_brightness_show(struct device * dev,struct device_attribute * attr,char * buf)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
led_brightness_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t size)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 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
led_max_brightness_show(struct device * dev,struct device_attribute * attr,char * buf)66 static 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
74 static 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
led_timer_function(unsigned long data)83 static 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
led_stop_software_blink(struct led_classdev * led_cdev)113 static void led_stop_software_blink(struct led_classdev *led_cdev)
114 {
115 /* deactivate previous settings */
116 del_timer_sync(&led_cdev->blink_timer);
117 led_cdev->blink_delay_on = 0;
118 led_cdev->blink_delay_off = 0;
119 }
120
led_set_software_blink(struct led_classdev * led_cdev,unsigned long delay_on,unsigned long delay_off)121 static void led_set_software_blink(struct led_classdev *led_cdev,
122 unsigned long delay_on,
123 unsigned long delay_off)
124 {
125 int current_brightness;
126
127 current_brightness = led_get_brightness(led_cdev);
128 if (current_brightness)
129 led_cdev->blink_brightness = current_brightness;
130 if (!led_cdev->blink_brightness)
131 led_cdev->blink_brightness = led_cdev->max_brightness;
132
133 if (led_get_trigger_data(led_cdev) &&
134 delay_on == led_cdev->blink_delay_on &&
135 delay_off == led_cdev->blink_delay_off)
136 return;
137
138 led_stop_software_blink(led_cdev);
139
140 led_cdev->blink_delay_on = delay_on;
141 led_cdev->blink_delay_off = delay_off;
142
143 /* never on - don't blink */
144 if (!delay_on)
145 return;
146
147 /* never off - just set to brightness */
148 if (!delay_off) {
149 led_set_brightness(led_cdev, led_cdev->blink_brightness);
150 return;
151 }
152
153 mod_timer(&led_cdev->blink_timer, jiffies + 1);
154 }
155
156
157 /**
158 * led_classdev_suspend - suspend an led_classdev.
159 * @led_cdev: the led_classdev to suspend.
160 */
led_classdev_suspend(struct led_classdev * led_cdev)161 void led_classdev_suspend(struct led_classdev *led_cdev)
162 {
163 led_cdev->flags |= LED_SUSPENDED;
164 led_cdev->brightness_set(led_cdev, 0);
165 }
166 EXPORT_SYMBOL_GPL(led_classdev_suspend);
167
168 /**
169 * led_classdev_resume - resume an led_classdev.
170 * @led_cdev: the led_classdev to resume.
171 */
led_classdev_resume(struct led_classdev * led_cdev)172 void led_classdev_resume(struct led_classdev *led_cdev)
173 {
174 led_cdev->brightness_set(led_cdev, led_cdev->brightness);
175 led_cdev->flags &= ~LED_SUSPENDED;
176 }
177 EXPORT_SYMBOL_GPL(led_classdev_resume);
178
led_suspend(struct device * dev,pm_message_t state)179 static int led_suspend(struct device *dev, pm_message_t state)
180 {
181 struct led_classdev *led_cdev = dev_get_drvdata(dev);
182
183 if (led_cdev->flags & LED_CORE_SUSPENDRESUME)
184 led_classdev_suspend(led_cdev);
185
186 return 0;
187 }
188
led_resume(struct device * dev)189 static int led_resume(struct device *dev)
190 {
191 struct led_classdev *led_cdev = dev_get_drvdata(dev);
192
193 if (led_cdev->flags & LED_CORE_SUSPENDRESUME)
194 led_classdev_resume(led_cdev);
195
196 return 0;
197 }
198
199 /**
200 * led_classdev_register - register a new object of led_classdev class.
201 * @parent: The device to register.
202 * @led_cdev: the led_classdev structure for this device.
203 */
led_classdev_register(struct device * parent,struct led_classdev * led_cdev)204 int led_classdev_register(struct device *parent, struct led_classdev *led_cdev)
205 {
206 led_cdev->dev = device_create(leds_class, parent, 0, led_cdev,
207 "%s", led_cdev->name);
208 if (IS_ERR(led_cdev->dev))
209 return PTR_ERR(led_cdev->dev);
210
211 #ifdef CONFIG_LEDS_TRIGGERS
212 init_rwsem(&led_cdev->trigger_lock);
213 #endif
214 /* add to the list of leds */
215 down_write(&leds_list_lock);
216 list_add_tail(&led_cdev->node, &leds_list);
217 up_write(&leds_list_lock);
218
219 if (!led_cdev->max_brightness)
220 led_cdev->max_brightness = LED_FULL;
221
222 led_update_brightness(led_cdev);
223
224 init_timer(&led_cdev->blink_timer);
225 led_cdev->blink_timer.function = led_timer_function;
226 led_cdev->blink_timer.data = (unsigned long)led_cdev;
227
228 #ifdef CONFIG_LEDS_TRIGGERS
229 led_trigger_set_default(led_cdev);
230 #endif
231
232 printk(KERN_DEBUG "Registered led device: %s\n",
233 led_cdev->name);
234
235 return 0;
236 }
237 EXPORT_SYMBOL_GPL(led_classdev_register);
238
239 /**
240 * led_classdev_unregister - unregisters a object of led_properties class.
241 * @led_cdev: the led device to unregister
242 *
243 * Unregisters a previously registered via led_classdev_register object.
244 */
led_classdev_unregister(struct led_classdev * led_cdev)245 void led_classdev_unregister(struct led_classdev *led_cdev)
246 {
247 #ifdef CONFIG_LEDS_TRIGGERS
248 down_write(&led_cdev->trigger_lock);
249 if (led_cdev->trigger)
250 led_trigger_set(led_cdev, NULL);
251 up_write(&led_cdev->trigger_lock);
252 #endif
253
254 /* Stop blinking */
255 led_brightness_set(led_cdev, LED_OFF);
256
257 device_unregister(led_cdev->dev);
258
259 down_write(&leds_list_lock);
260 list_del(&led_cdev->node);
261 up_write(&leds_list_lock);
262 }
263 EXPORT_SYMBOL_GPL(led_classdev_unregister);
264
led_blink_set(struct led_classdev * led_cdev,unsigned long * delay_on,unsigned long * delay_off)265 void led_blink_set(struct led_classdev *led_cdev,
266 unsigned long *delay_on,
267 unsigned long *delay_off)
268 {
269 del_timer_sync(&led_cdev->blink_timer);
270
271 if (led_cdev->blink_set &&
272 !led_cdev->blink_set(led_cdev, delay_on, delay_off))
273 return;
274
275 /* blink with 1 Hz as default if nothing specified */
276 if (!*delay_on && !*delay_off)
277 *delay_on = *delay_off = 500;
278
279 led_set_software_blink(led_cdev, *delay_on, *delay_off);
280 }
281 EXPORT_SYMBOL(led_blink_set);
282
led_brightness_set(struct led_classdev * led_cdev,enum led_brightness brightness)283 void led_brightness_set(struct led_classdev *led_cdev,
284 enum led_brightness brightness)
285 {
286 led_stop_software_blink(led_cdev);
287 led_cdev->brightness_set(led_cdev, brightness);
288 }
289 EXPORT_SYMBOL(led_brightness_set);
290
leds_init(void)291 static int __init leds_init(void)
292 {
293 leds_class = class_create(THIS_MODULE, "leds");
294 if (IS_ERR(leds_class))
295 return PTR_ERR(leds_class);
296 leds_class->suspend = led_suspend;
297 leds_class->resume = led_resume;
298 leds_class->dev_attrs = led_class_attrs;
299 return 0;
300 }
301
leds_exit(void)302 static void __exit leds_exit(void)
303 {
304 class_destroy(leds_class);
305 }
306
307 subsys_initcall(leds_init);
308 module_exit(leds_exit);
309
310 MODULE_AUTHOR("John Lenz, Richard Purdie");
311 MODULE_LICENSE("GPL");
312 MODULE_DESCRIPTION("LED Class Interface");
313