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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>
28#include "leds.h"
29
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;
Shuah Khan0da3e652012-06-13 10:01:37 +080044 __led_set_brightness(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;
Shuah Khan0da3e652012-06-13 10:01:37 +080075 __led_set_brightness(led_cdev, transient_data->restore_state);
Shuah Khan44e1e9f2012-05-29 15:07:30 -070076 return size;
77 }
78
79 /* start timer if there is no active timer */
80 if (state == 1 && transient_data->activate == 0 &&
81 transient_data->duration != 0) {
82 transient_data->activate = state;
Shuah Khan0da3e652012-06-13 10:01:37 +080083 __led_set_brightness(led_cdev, transient_data->state);
Shuah Khan44e1e9f2012-05-29 15:07:30 -070084 transient_data->restore_state =
85 (transient_data->state == LED_FULL) ? LED_OFF : LED_FULL;
86 mod_timer(&transient_data->timer,
87 jiffies + transient_data->duration);
88 }
89
90 /* state == 0 && transient_data->activate == 0
91 timer is not active - just return */
92 /* state == 1 && transient_data->activate == 1
93 timer is already active - just return */
94
95 return size;
96}
97
98static ssize_t transient_duration_show(struct device *dev,
99 struct device_attribute *attr, char *buf)
100{
101 struct led_classdev *led_cdev = dev_get_drvdata(dev);
102 struct transient_trig_data *transient_data = led_cdev->trigger_data;
103
104 return sprintf(buf, "%lu\n", transient_data->duration);
105}
106
107static ssize_t transient_duration_store(struct device *dev,
108 struct device_attribute *attr, const char *buf, size_t size)
109{
110 struct led_classdev *led_cdev = dev_get_drvdata(dev);
111 struct transient_trig_data *transient_data = led_cdev->trigger_data;
112 unsigned long state;
113 ssize_t ret;
114
115 ret = kstrtoul(buf, 10, &state);
116 if (ret)
117 return ret;
118
119 transient_data->duration = state;
120 return size;
121}
122
123static ssize_t transient_state_show(struct device *dev,
124 struct device_attribute *attr, char *buf)
125{
126 struct led_classdev *led_cdev = dev_get_drvdata(dev);
127 struct transient_trig_data *transient_data = led_cdev->trigger_data;
128 int state;
129
130 state = (transient_data->state == LED_FULL) ? 1 : 0;
131 return sprintf(buf, "%d\n", state);
132}
133
134static ssize_t transient_state_store(struct device *dev,
135 struct device_attribute *attr, const char *buf, size_t size)
136{
137 struct led_classdev *led_cdev = dev_get_drvdata(dev);
138 struct transient_trig_data *transient_data = led_cdev->trigger_data;
139 unsigned long state;
140 ssize_t ret;
141
142 ret = kstrtoul(buf, 10, &state);
143 if (ret)
144 return ret;
145
146 if (state != 1 && state != 0)
147 return -EINVAL;
148
149 transient_data->state = (state == 1) ? LED_FULL : LED_OFF;
150 return size;
151}
152
153static DEVICE_ATTR(activate, 0644, transient_activate_show,
154 transient_activate_store);
155static DEVICE_ATTR(duration, 0644, transient_duration_show,
156 transient_duration_store);
157static DEVICE_ATTR(state, 0644, transient_state_show, transient_state_store);
158
159static void transient_trig_activate(struct led_classdev *led_cdev)
160{
161 int rc;
162 struct transient_trig_data *tdata;
163
164 tdata = kzalloc(sizeof(struct transient_trig_data), GFP_KERNEL);
165 if (!tdata) {
166 dev_err(led_cdev->dev,
167 "unable to allocate transient trigger\n");
168 return;
169 }
170 led_cdev->trigger_data = tdata;
171
172 rc = device_create_file(led_cdev->dev, &dev_attr_activate);
173 if (rc)
174 goto err_out;
175
176 rc = device_create_file(led_cdev->dev, &dev_attr_duration);
177 if (rc)
178 goto err_out_duration;
179
180 rc = device_create_file(led_cdev->dev, &dev_attr_state);
181 if (rc)
182 goto err_out_state;
183
184 setup_timer(&tdata->timer, transient_timer_function,
185 (unsigned long) led_cdev);
186 led_cdev->activated = true;
187
188 return;
189
190err_out_state:
191 device_remove_file(led_cdev->dev, &dev_attr_duration);
192err_out_duration:
193 device_remove_file(led_cdev->dev, &dev_attr_activate);
194err_out:
195 dev_err(led_cdev->dev, "unable to register transient trigger\n");
196 led_cdev->trigger_data = NULL;
197 kfree(tdata);
198}
199
200static void transient_trig_deactivate(struct led_classdev *led_cdev)
201{
202 struct transient_trig_data *transient_data = led_cdev->trigger_data;
203
204 if (led_cdev->activated) {
205 del_timer_sync(&transient_data->timer);
Shuah Khan0da3e652012-06-13 10:01:37 +0800206 __led_set_brightness(led_cdev, transient_data->restore_state);
Shuah Khan44e1e9f2012-05-29 15:07:30 -0700207 device_remove_file(led_cdev->dev, &dev_attr_activate);
208 device_remove_file(led_cdev->dev, &dev_attr_duration);
209 device_remove_file(led_cdev->dev, &dev_attr_state);
210 led_cdev->trigger_data = NULL;
211 led_cdev->activated = false;
212 kfree(transient_data);
213 }
214}
215
216static struct led_trigger transient_trigger = {
217 .name = "transient",
218 .activate = transient_trig_activate,
219 .deactivate = transient_trig_deactivate,
220};
221
222static int __init transient_trig_init(void)
223{
224 return led_trigger_register(&transient_trigger);
225}
226
227static void __exit transient_trig_exit(void)
228{
229 led_trigger_unregister(&transient_trigger);
230}
231
232module_init(transient_trig_init);
233module_exit(transient_trig_exit);
234
235MODULE_AUTHOR("Shuah Khan <shuahkhan@gmail.com>");
236MODULE_DESCRIPTION("Transient LED trigger");
237MODULE_LICENSE("GPL");