aboutsummaryrefslogtreecommitdiff
path: root/drivers/leds/trigger/ledtrig-transient.c
blob: 3c34de404d181012dab17fd1965e8b48efd4b371 (plain)
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
/*
 * LED Kernel Transient Trigger
 *
 * Copyright (C) 2012 Shuah Khan <shuahkhan@gmail.com>
 *
 * Based on Richard Purdie's ledtrig-timer.c and Atsushi Nemoto's
 * ledtrig-heartbeat.c
 * Design and use-case input from Jonas Bonn <jonas@southpole.se> and
 * Neil Brown <neilb@suse.de>
 *
 * 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.
 *
 */
/*
 * Transient trigger allows one shot timer activation. Please refer to
 * Documentation/leds/ledtrig-transient.txt for details
*/

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/slab.h>
#include <linux/timer.h>
#include <linux/leds.h>
#include "../leds.h"

struct transient_trig_data {
	int activate;
	int state;
	int restore_state;
	unsigned long duration;
	struct timer_list timer;
};

static void transient_timer_function(unsigned long data)
{
	struct led_classdev *led_cdev = (struct led_classdev *) data;
	struct transient_trig_data *transient_data = led_cdev->trigger_data;

	transient_data->activate = 0;
	led_set_brightness_async(led_cdev, transient_data->restore_state);
}

static ssize_t transient_activate_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct led_classdev *led_cdev = dev_get_drvdata(dev);
	struct transient_trig_data *transient_data = led_cdev->trigger_data;

	return sprintf(buf, "%d\n", transient_data->activate);
}

static ssize_t transient_activate_store(struct device *dev,
		struct device_attribute *attr, const char *buf, size_t size)
{
	struct led_classdev *led_cdev = dev_get_drvdata(dev);
	struct transient_trig_data *transient_data = led_cdev->trigger_data;
	unsigned long state;
	ssize_t ret;

	ret = kstrtoul(buf, 10, &state);
	if (ret)
		return ret;

	if (state != 1 && state != 0)
		return -EINVAL;

	/* cancel the running timer */
	if (state == 0 && transient_data->activate == 1) {
		del_timer(&transient_data->timer);
		transient_data->activate = state;
		led_set_brightness_async(led_cdev,
					transient_data->restore_state);
		return size;
	}

	/* start timer if there is no active timer */
	if (state == 1 && transient_data->activate == 0 &&
	    transient_data->duration != 0) {
		transient_data->activate = state;
		led_set_brightness_async(led_cdev, transient_data->state);
		transient_data->restore_state =
		    (transient_data->state == LED_FULL) ? LED_OFF : LED_FULL;
		mod_timer(&transient_data->timer,
			  jiffies + transient_data->duration);
	}

	/* state == 0 && transient_data->activate == 0
		timer is not active - just return */
	/* state == 1 && transient_data->activate == 1
		timer is already active - just return */

	return size;
}

static ssize_t transient_duration_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct led_classdev *led_cdev = dev_get_drvdata(dev);
	struct transient_trig_data *transient_data = led_cdev->trigger_data;

	return sprintf(buf, "%lu\n", transient_data->duration);
}

static ssize_t transient_duration_store(struct device *dev,
		struct device_attribute *attr, const char *buf, size_t size)
{
	struct led_classdev *led_cdev = dev_get_drvdata(dev);
	struct transient_trig_data *transient_data = led_cdev->trigger_data;
	unsigned long state;
	ssize_t ret;

	ret = kstrtoul(buf, 10, &state);
	if (ret)
		return ret;

	transient_data->duration = state;
	return size;
}

static ssize_t transient_state_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct led_classdev *led_cdev = dev_get_drvdata(dev);
	struct transient_trig_data *transient_data = led_cdev->trigger_data;
	int state;

	state = (transient_data->state == LED_FULL) ? 1 : 0;
	return sprintf(buf, "%d\n", state);
}

static ssize_t transient_state_store(struct device *dev,
		struct device_attribute *attr, const char *buf, size_t size)
{
	struct led_classdev *led_cdev = dev_get_drvdata(dev);
	struct transient_trig_data *transient_data = led_cdev->trigger_data;
	unsigned long state;
	ssize_t ret;

	ret = kstrtoul(buf, 10, &state);
	if (ret)
		return ret;

	if (state != 1 && state != 0)
		return -EINVAL;

	transient_data->state = (state == 1) ? LED_FULL : LED_OFF;
	return size;
}

static DEVICE_ATTR(activate, 0644, transient_activate_show,
		   transient_activate_store);
static DEVICE_ATTR(duration, 0644, transient_duration_show,
		   transient_duration_store);
static DEVICE_ATTR(state, 0644, transient_state_show, transient_state_store);

static void transient_trig_activate(struct led_classdev *led_cdev)
{
	int rc;
	struct transient_trig_data *tdata;

	tdata = kzalloc(sizeof(struct transient_trig_data), GFP_KERNEL);
	if (!tdata) {
		dev_err(led_cdev->dev,
			"unable to allocate transient trigger\n");
		return;
	}
	led_cdev->trigger_data = tdata;

	rc = device_create_file(led_cdev->dev, &dev_attr_activate);
	if (rc)
		goto err_out;

	rc = device_create_file(led_cdev->dev, &dev_attr_duration);
	if (rc)
		goto err_out_duration;

	rc = device_create_file(led_cdev->dev, &dev_attr_state);
	if (rc)
		goto err_out_state;

	setup_timer(&tdata->timer, transient_timer_function,
		    (unsigned long) led_cdev);
	led_cdev->activated = true;

	return;

err_out_state:
	device_remove_file(led_cdev->dev, &dev_attr_duration);
err_out_duration:
	device_remove_file(led_cdev->dev, &dev_attr_activate);
err_out:
	dev_err(led_cdev->dev, "unable to register transient trigger\n");
	led_cdev->trigger_data = NULL;
	kfree(tdata);
}

static void transient_trig_deactivate(struct led_classdev *led_cdev)
{
	struct transient_trig_data *transient_data = led_cdev->trigger_data;

	if (led_cdev->activated) {
		del_timer_sync(&transient_data->timer);
		led_set_brightness_async(led_cdev,
					transient_data->restore_state);
		device_remove_file(led_cdev->dev, &dev_attr_activate);
		device_remove_file(led_cdev->dev, &dev_attr_duration);
		device_remove_file(led_cdev->dev, &dev_attr_state);
		led_cdev->trigger_data = NULL;
		led_cdev->activated = false;
		kfree(transient_data);
	}
}

static struct led_trigger transient_trigger = {
	.name     = "transient",
	.activate = transient_trig_activate,
	.deactivate = transient_trig_deactivate,
};

static int __init transient_trig_init(void)
{
	return led_trigger_register(&transient_trigger);
}

static void __exit transient_trig_exit(void)
{
	led_trigger_unregister(&transient_trigger);
}

module_init(transient_trig_init);
module_exit(transient_trig_exit);

MODULE_AUTHOR("Shuah Khan <shuahkhan@gmail.com>");
MODULE_DESCRIPTION("Transient LED trigger");
MODULE_LICENSE("GPL");