aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/leds/led-class.c
blob: dc3d3d83191a043de95e7e7b41a5aa47cf57100c (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
/*
 * LED Class Core
 *
 * Copyright (C) 2005 John Lenz <lenz@cs.wisc.edu>
 * Copyright (C) 2005-2007 Richard Purdie <rpurdie@openedhand.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/device.h>
#include <linux/sysdev.h>
#include <linux/timer.h>
#include <linux/err.h>
#include <linux/ctype.h>
#include <linux/leds.h>
#include "leds.h"

static struct class *leds_class;

static void led_update_brightness(struct led_classdev *led_cdev)
{
	if (led_cdev->brightness_get)
		led_cdev->brightness = led_cdev->brightness_get(led_cdev);
}

static ssize_t led_brightness_show(struct device *dev, 
		struct device_attribute *attr, char *buf)
{
	struct led_classdev *led_cdev = dev_get_drvdata(dev);

	/* no lock needed for this */
	led_update_brightness(led_cdev);

	return sprintf(buf, "%u\n", led_cdev->brightness);
}

static ssize_t led_brightness_store(struct device *dev,
		struct device_attribute *attr, const char *buf, size_t size)
{
	struct led_classdev *led_cdev = dev_get_drvdata(dev);
	ssize_t ret = -EINVAL;
	char *after;
	unsigned long state = simple_strtoul(buf, &after, 10);
	size_t count = after - buf;

	if (isspace(*after))
		count++;

	if (count == size) {
		ret = count;

		if (state == LED_OFF)
			led_trigger_remove(led_cdev);
		led_set_brightness(led_cdev, state);
	}

	return ret;
}

static ssize_t led_max_brightness_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct led_classdev *led_cdev = dev_get_drvdata(dev);

	return sprintf(buf, "%u\n", led_cdev->max_brightness);
}

static struct device_attribute led_class_attrs[] = {
	__ATTR(brightness, 0644, led_brightness_show, led_brightness_store),
	__ATTR(max_brightness, 0444, led_max_brightness_show, NULL),
#ifdef CONFIG_LEDS_TRIGGERS
	__ATTR(trigger, 0644, led_trigger_show, led_trigger_store),
#endif
	__ATTR_NULL,
};

static void led_timer_function(unsigned long data)
{
	struct led_classdev *led_cdev = (void *)data;
	unsigned long brightness;
	unsigned long delay;

	if (!led_cdev->blink_delay_on || !led_cdev->blink_delay_off) {
		led_set_brightness(led_cdev, LED_OFF);
		return;
	}

	brightness = led_get_brightness(led_cdev);
	if (!brightness) {
		/* Time to switch the LED on. */
		brightness = led_cdev->blink_brightness;
		delay = led_cdev->blink_delay_on;
	} else {
		/* Store the current brightness value to be able
		 * to restore it when the delay_off period is over.
		 */
		led_cdev->blink_brightness = brightness;
		brightness = LED_OFF;
		delay = led_cdev->blink_delay_off;
	}

	led_set_brightness(led_cdev, brightness);

	mod_timer(&led_cdev->blink_timer, jiffies + msecs_to_jiffies(delay));
}

static void led_stop_software_blink(struct led_classdev *led_cdev)
{
	/* deactivate previous settings */
	del_timer_sync(&led_cdev->blink_timer);
	led_cdev->blink_delay_on = 0;
	led_cdev->blink_delay_off = 0;
}

static void led_set_software_blink(struct led_classdev *led_cdev,
				   unsigned long delay_on,
				   unsigned long delay_off)
{
	int current_brightness;

	current_brightness = led_get_brightness(led_cdev);
	if (current_brightness)
		led_cdev->blink_brightness = current_brightness;
	if (!led_cdev->blink_brightness)
		led_cdev->blink_brightness = led_cdev->max_brightness;

	if (led_get_trigger_data(led_cdev) &&
	    delay_on == led_cdev->blink_delay_on &&
	    delay_off == led_cdev->blink_delay_off)
		return;

	led_stop_software_blink(led_cdev);

	led_cdev->blink_delay_on = delay_on;
	led_cdev->blink_delay_off = delay_off;

	/* never on - don't blink */
	if (!delay_on)
		return;

	/* never off - just set to brightness */
	if (!delay_off) {
		led_set_brightness(led_cdev, led_cdev->blink_brightness);
		return;
	}

	mod_timer(&led_cdev->blink_timer, jiffies + 1);
}


/**
 * led_classdev_suspend - suspend an led_classdev.
 * @led_cdev: the led_classdev to suspend.
 */
void led_classdev_suspend(struct led_classdev *led_cdev)
{
	led_cdev->flags |= LED_SUSPENDED;
	led_cdev->brightness_set(led_cdev, 0);
}
EXPORT_SYMBOL_GPL(led_classdev_suspend);

/**
 * led_classdev_resume - resume an led_classdev.
 * @led_cdev: the led_classdev to resume.
 */
void led_classdev_resume(struct led_classdev *led_cdev)
{
	led_cdev->brightness_set(led_cdev, led_cdev->brightness);
	led_cdev->flags &= ~LED_SUSPENDED;
}
EXPORT_SYMBOL_GPL(led_classdev_resume);

static int led_suspend(struct device *dev, pm_message_t state)
{
	struct led_classdev *led_cdev = dev_get_drvdata(dev);

	if (led_cdev->flags & LED_CORE_SUSPENDRESUME)
		led_classdev_suspend(led_cdev);

	return 0;
}

static int led_resume(struct device *dev)
{
	struct led_classdev *led_cdev = dev_get_drvdata(dev);

	if (led_cdev->flags & LED_CORE_SUSPENDRESUME)
		led_classdev_resume(led_cdev);

	return 0;
}

/**
 * led_classdev_register - register a new object of led_classdev class.
 * @parent: The device to register.
 * @led_cdev: the led_classdev structure for this device.
 */
int led_classdev_register(struct device *parent, struct led_classdev *led_cdev)
{
	led_cdev->dev = device_create(leds_class, parent, 0, led_cdev,
				      "%s", led_cdev->name);
	if (IS_ERR(led_cdev->dev))
		return PTR_ERR(led_cdev->dev);

#ifdef CONFIG_LEDS_TRIGGERS
	init_rwsem(&led_cdev->trigger_lock);
#endif
	/* add to the list of leds */
	down_write(&leds_list_lock);
	list_add_tail(&led_cdev->node, &leds_list);
	up_write(&leds_list_lock);

	if (!led_cdev->max_brightness)
		led_cdev->max_brightness = LED_FULL;

	led_update_brightness(led_cdev);

	init_timer(&led_cdev->blink_timer);
	led_cdev->blink_timer.function = led_timer_function;
	led_cdev->blink_timer.data = (unsigned long)led_cdev;

#ifdef CONFIG_LEDS_TRIGGERS
	led_trigger_set_default(led_cdev);
#endif

	printk(KERN_DEBUG "Registered led device: %s\n",
			led_cdev->name);

	return 0;
}
EXPORT_SYMBOL_GPL(led_classdev_register);

/**
 * led_classdev_unregister - unregisters a object of led_properties class.
 * @led_cdev: the led device to unregister
 *
 * Unregisters a previously registered via led_classdev_register object.
 */
void led_classdev_unregister(struct led_classdev *led_cdev)
{
#ifdef CONFIG_LEDS_TRIGGERS
	down_write(&led_cdev->trigger_lock);
	if (led_cdev->trigger)
		led_trigger_set(led_cdev, NULL);
	up_write(&led_cdev->trigger_lock);
#endif

	/* Stop blinking */
	led_brightness_set(led_cdev, LED_OFF);

	device_unregister(led_cdev->dev);

	down_write(&leds_list_lock);
	list_del(&led_cdev->node);
	up_write(&leds_list_lock);
}
EXPORT_SYMBOL_GPL(led_classdev_unregister);

void led_blink_set(struct led_classdev *led_cdev,
		   unsigned long *delay_on,
		   unsigned long *delay_off)
{
	if (led_cdev->blink_set &&
	    !led_cdev->blink_set(led_cdev, delay_on, delay_off))
		return;

	/* blink with 1 Hz as default if nothing specified */
	if (!*delay_on && !*delay_off)
		*delay_on = *delay_off = 500;

	led_set_software_blink(led_cdev, *delay_on, *delay_off);
}
EXPORT_SYMBOL(led_blink_set);

void led_brightness_set(struct led_classdev *led_cdev,
			enum led_brightness brightness)
{
	led_stop_software_blink(led_cdev);
	led_cdev->brightness_set(led_cdev, brightness);
}
EXPORT_SYMBOL(led_brightness_set);

static int __init leds_init(void)
{
	leds_class = class_create(THIS_MODULE, "leds");
	if (IS_ERR(leds_class))
		return PTR_ERR(leds_class);
	leds_class->suspend = led_suspend;
	leds_class->resume = led_resume;
	leds_class->dev_attrs = led_class_attrs;
	return 0;
}

static void __exit leds_exit(void)
{
	class_destroy(leds_class);
}

subsys_initcall(leds_init);
module_exit(leds_exit);

MODULE_AUTHOR("John Lenz, Richard Purdie");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("LED Class Interface");