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Shuah Khan44e1e9f2012-05-29 15:07:30 -07001/*
2 * LED Kernel Transient Trigger
3 *
4 * Copyright (C) 2012 Shuah Khan <shuahkhan@gmail.com>
5 *
6 * Based on Richard Purdie's ledtrig-timer.c and Atsushi Nemoto's
7 * ledtrig-heartbeat.c
8 * Design and use-case input from Jonas Bonn <jonas@southpole.se> and
9 * Neil Brown <neilb@suse.de>
10 *
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License version 2 as
13 * published by the Free Software Foundation.
14 *
15 */
16/*
17 * Transient trigger allows one shot timer activation. Please refer to
18 * Documentation/leds/ledtrig-transient.txt for details
19*/
20
21#include <linux/module.h>
22#include <linux/kernel.h>
23#include <linux/init.h>
24#include <linux/device.h>
25#include <linux/slab.h>
26#include <linux/timer.h>
27#include <linux/leds.h>
Kim, Milof07fb522013-02-20 00:36:01 -080028#include "../leds.h"
Shuah Khan44e1e9f2012-05-29 15:07:30 -070029
30struct transient_trig_data {
31 int activate;
32 int state;
33 int restore_state;
34 unsigned long duration;
35 struct timer_list timer;
36};
37
38static void transient_timer_function(unsigned long data)
39{
40 struct led_classdev *led_cdev = (struct led_classdev *) data;
41 struct transient_trig_data *transient_data = led_cdev->trigger_data;
42
43 transient_data->activate = 0;
Jacek Anaszewski4d71a4a2014-11-14 02:50:18 -080044 led_set_brightness_async(led_cdev, transient_data->restore_state);
Shuah Khan44e1e9f2012-05-29 15:07:30 -070045}
46
47static ssize_t transient_activate_show(struct device *dev,
48 struct device_attribute *attr, char *buf)
49{
50 struct led_classdev *led_cdev = dev_get_drvdata(dev);
51 struct transient_trig_data *transient_data = led_cdev->trigger_data;
52
53 return sprintf(buf, "%d\n", transient_data->activate);
54}
55
56static ssize_t transient_activate_store(struct device *dev,
57 struct device_attribute *attr, const char *buf, size_t size)
58{
59 struct led_classdev *led_cdev = dev_get_drvdata(dev);
60 struct transient_trig_data *transient_data = led_cdev->trigger_data;
61 unsigned long state;
62 ssize_t ret;
63
64 ret = kstrtoul(buf, 10, &state);
65 if (ret)
66 return ret;
67
68 if (state != 1 && state != 0)
69 return -EINVAL;
70
71 /* cancel the running timer */
72 if (state == 0 && transient_data->activate == 1) {
73 del_timer(&transient_data->timer);
74 transient_data->activate = state;
Jacek Anaszewski4d71a4a2014-11-14 02:50:18 -080075 led_set_brightness_async(led_cdev,
76 transient_data->restore_state);
Shuah Khan44e1e9f2012-05-29 15:07:30 -070077 return size;
78 }
79
80 /* start timer if there is no active timer */
81 if (state == 1 && transient_data->activate == 0 &&
82 transient_data->duration != 0) {
83 transient_data->activate = state;
Jacek Anaszewski4d71a4a2014-11-14 02:50:18 -080084 led_set_brightness_async(led_cdev, transient_data->state);
Shuah Khan44e1e9f2012-05-29 15:07:30 -070085 transient_data->restore_state =
86 (transient_data->state == LED_FULL) ? LED_OFF : LED_FULL;
87 mod_timer(&transient_data->timer,
88 jiffies + transient_data->duration);
89 }
90
91 /* state == 0 && transient_data->activate == 0
92 timer is not active - just return */
93 /* state == 1 && transient_data->activate == 1
94 timer is already active - just return */
95
96 return size;
97}
98
99static ssize_t transient_duration_show(struct device *dev,
100 struct device_attribute *attr, char *buf)
101{
102 struct led_classdev *led_cdev = dev_get_drvdata(dev);
103 struct transient_trig_data *transient_data = led_cdev->trigger_data;
104
105 return sprintf(buf, "%lu\n", transient_data->duration);
106}
107
108static ssize_t transient_duration_store(struct device *dev,
109 struct device_attribute *attr, const char *buf, size_t size)
110{
111 struct led_classdev *led_cdev = dev_get_drvdata(dev);
112 struct transient_trig_data *transient_data = led_cdev->trigger_data;
113 unsigned long state;
114 ssize_t ret;
115
116 ret = kstrtoul(buf, 10, &state);
117 if (ret)
118 return ret;
119
120 transient_data->duration = state;
121 return size;
122}
123
124static ssize_t transient_state_show(struct device *dev,
125 struct device_attribute *attr, char *buf)
126{
127 struct led_classdev *led_cdev = dev_get_drvdata(dev);
128 struct transient_trig_data *transient_data = led_cdev->trigger_data;
129 int state;
130
131 state = (transient_data->state == LED_FULL) ? 1 : 0;
132 return sprintf(buf, "%d\n", state);
133}
134
135static ssize_t transient_state_store(struct device *dev,
136 struct device_attribute *attr, const char *buf, size_t size)
137{
138 struct led_classdev *led_cdev = dev_get_drvdata(dev);
139 struct transient_trig_data *transient_data = led_cdev->trigger_data;
140 unsigned long state;
141 ssize_t ret;
142
143 ret = kstrtoul(buf, 10, &state);
144 if (ret)
145 return ret;
146
147 if (state != 1 && state != 0)
148 return -EINVAL;
149
150 transient_data->state = (state == 1) ? LED_FULL : LED_OFF;
151 return size;
152}
153
154static DEVICE_ATTR(activate, 0644, transient_activate_show,
155 transient_activate_store);
156static DEVICE_ATTR(duration, 0644, transient_duration_show,
157 transient_duration_store);
158static DEVICE_ATTR(state, 0644, transient_state_show, transient_state_store);
159
160static void transient_trig_activate(struct led_classdev *led_cdev)
161{
162 int rc;
163 struct transient_trig_data *tdata;
164
165 tdata = kzalloc(sizeof(struct transient_trig_data), GFP_KERNEL);
166 if (!tdata) {
167 dev_err(led_cdev->dev,
168 "unable to allocate transient trigger\n");
169 return;
170 }
171 led_cdev->trigger_data = tdata;
172
173 rc = device_create_file(led_cdev->dev, &dev_attr_activate);
174 if (rc)
175 goto err_out;
176
177 rc = device_create_file(led_cdev->dev, &dev_attr_duration);
178 if (rc)
179 goto err_out_duration;
180
181 rc = device_create_file(led_cdev->dev, &dev_attr_state);
182 if (rc)
183 goto err_out_state;
184
185 setup_timer(&tdata->timer, transient_timer_function,
186 (unsigned long) led_cdev);
187 led_cdev->activated = true;
188
189 return;
190
191err_out_state:
192 device_remove_file(led_cdev->dev, &dev_attr_duration);
193err_out_duration:
194 device_remove_file(led_cdev->dev, &dev_attr_activate);
195err_out:
196 dev_err(led_cdev->dev, "unable to register transient trigger\n");
197 led_cdev->trigger_data = NULL;
198 kfree(tdata);
199}
200
201static void transient_trig_deactivate(struct led_classdev *led_cdev)
202{
203 struct transient_trig_data *transient_data = led_cdev->trigger_data;
204
205 if (led_cdev->activated) {
206 del_timer_sync(&transient_data->timer);
Jacek Anaszewski4d71a4a2014-11-14 02:50:18 -0800207 led_set_brightness_async(led_cdev,
208 transient_data->restore_state);
Shuah Khan44e1e9f2012-05-29 15:07:30 -0700209 device_remove_file(led_cdev->dev, &dev_attr_activate);
210 device_remove_file(led_cdev->dev, &dev_attr_duration);
211 device_remove_file(led_cdev->dev, &dev_attr_state);
212 led_cdev->trigger_data = NULL;
213 led_cdev->activated = false;
214 kfree(transient_data);
215 }
216}
217
218static struct led_trigger transient_trigger = {
219 .name = "transient",
220 .activate = transient_trig_activate,
221 .deactivate = transient_trig_deactivate,
222};
223
224static int __init transient_trig_init(void)
225{
226 return led_trigger_register(&transient_trigger);
227}
228
229static void __exit transient_trig_exit(void)
230{
231 led_trigger_unregister(&transient_trigger);
232}
233
234module_init(transient_trig_init);
235module_exit(transient_trig_exit);
236
237MODULE_AUTHOR("Shuah Khan <shuahkhan@gmail.com>");
238MODULE_DESCRIPTION("Transient LED trigger");
239MODULE_LICENSE("GPL");