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1 | /* |
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 | ||
30 | struct transient_trig_data { | |
31 | int activate; | |
32 | int state; | |
33 | int restore_state; | |
34 | unsigned long duration; | |
35 | struct timer_list timer; | |
36 | }; | |
37 | ||
38 | static 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; | |
0da3e65b | 44 | __led_set_brightness(led_cdev, transient_data->restore_state); |
44e1e9f8 SK |
45 | } |
46 | ||
47 | static 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 | ||
56 | static 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; | |
0da3e65b | 75 | __led_set_brightness(led_cdev, transient_data->restore_state); |
44e1e9f8 SK |
76 | 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; | |
0da3e65b | 83 | __led_set_brightness(led_cdev, transient_data->state); |
44e1e9f8 SK |
84 | 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 | ||
98 | static 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 | ||
107 | static 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 | ||
123 | static 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 | ||
134 | static 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 | ||
153 | static DEVICE_ATTR(activate, 0644, transient_activate_show, | |
154 | transient_activate_store); | |
155 | static DEVICE_ATTR(duration, 0644, transient_duration_show, | |
156 | transient_duration_store); | |
157 | static DEVICE_ATTR(state, 0644, transient_state_show, transient_state_store); | |
158 | ||
159 | static 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 | ||
190 | err_out_state: | |
191 | device_remove_file(led_cdev->dev, &dev_attr_duration); | |
192 | err_out_duration: | |
193 | device_remove_file(led_cdev->dev, &dev_attr_activate); | |
194 | err_out: | |
195 | dev_err(led_cdev->dev, "unable to register transient trigger\n"); | |
196 | led_cdev->trigger_data = NULL; | |
197 | kfree(tdata); | |
198 | } | |
199 | ||
200 | static 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); | |
0da3e65b | 206 | __led_set_brightness(led_cdev, transient_data->restore_state); |
44e1e9f8 SK |
207 | 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 | ||
216 | static struct led_trigger transient_trigger = { | |
217 | .name = "transient", | |
218 | .activate = transient_trig_activate, | |
219 | .deactivate = transient_trig_deactivate, | |
220 | }; | |
221 | ||
222 | static int __init transient_trig_init(void) | |
223 | { | |
224 | return led_trigger_register(&transient_trigger); | |
225 | } | |
226 | ||
227 | static void __exit transient_trig_exit(void) | |
228 | { | |
229 | led_trigger_unregister(&transient_trigger); | |
230 | } | |
231 | ||
232 | module_init(transient_trig_init); | |
233 | module_exit(transient_trig_exit); | |
234 | ||
235 | MODULE_AUTHOR("Shuah Khan <shuahkhan@gmail.com>"); | |
236 | MODULE_DESCRIPTION("Transient LED trigger"); | |
237 | MODULE_LICENSE("GPL"); |