tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * LED Kernel Timer Trigger
3 *
4 * Copyright 2005-2006 Openedhand Ltd.
5 *
6 * Author: Richard Purdie <rpurdie@openedhand.com>
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
11 *
12 */
13
14#include <linux/module.h>
15#include <linux/jiffies.h>
16#include <linux/kernel.h>
17#include <linux/init.h>
18#include <linux/list.h>
19#include <linux/spinlock.h>
20#include <linux/device.h>
21#include <linux/sysdev.h>
22#include <linux/timer.h>
23#include <linux/ctype.h>
24#include <linux/leds.h>
25#include "leds.h"
26
27struct timer_trig_data {
28 int brightness_on; /* LED brightness during "on" period.
29 * (LED_OFF < brightness_on <= LED_FULL)
30 */
31 unsigned long delay_on; /* milliseconds on */
32 unsigned long delay_off; /* milliseconds off */
33 struct timer_list timer;
34};
35
36static void led_timer_function(unsigned long data)
37{
38 struct led_classdev *led_cdev = (struct led_classdev *) data;
39 struct timer_trig_data *timer_data = led_cdev->trigger_data;
40 unsigned long brightness;
41 unsigned long delay;
42
43 if (!timer_data->delay_on || !timer_data->delay_off) {
44 led_set_brightness(led_cdev, LED_OFF);
45 return;
46 }
47
48 brightness = led_get_brightness(led_cdev);
49 if (!brightness) {
50 /* Time to switch the LED on. */
51 brightness = timer_data->brightness_on;
52 delay = timer_data->delay_on;
53 } else {
54 /* Store the current brightness value to be able
55 * to restore it when the delay_off period is over.
56 */
57 timer_data->brightness_on = brightness;
58 brightness = LED_OFF;
59 delay = timer_data->delay_off;
60 }
61
62 led_set_brightness(led_cdev, brightness);
63
64 mod_timer(&timer_data->timer, jiffies + msecs_to_jiffies(delay));
65}
66
67static ssize_t led_delay_on_show(struct device *dev,
68 struct device_attribute *attr, char *buf)
69{
70 struct led_classdev *led_cdev = dev_get_drvdata(dev);
71 struct timer_trig_data *timer_data = led_cdev->trigger_data;
72
73 return sprintf(buf, "%lu\n", timer_data->delay_on);
74}
75
76static ssize_t led_delay_on_store(struct device *dev,
77 struct device_attribute *attr, const char *buf, size_t size)
78{
79 struct led_classdev *led_cdev = dev_get_drvdata(dev);
80 struct timer_trig_data *timer_data = led_cdev->trigger_data;
81 int ret = -EINVAL;
82 char *after;
83 unsigned long state = simple_strtoul(buf, &after, 10);
84 size_t count = after - buf;
85
86 if (*after && isspace(*after))
87 count++;
88
89 if (count == size) {
90 if (timer_data->delay_on != state) {
91 /* the new value differs from the previous */
92 timer_data->delay_on = state;
93
94 /* deactivate previous settings */
95 del_timer_sync(&timer_data->timer);
96
97 /* try to activate hardware acceleration, if any */
98 if (!led_cdev->blink_set ||
99 led_cdev->blink_set(led_cdev,
100 &timer_data->delay_on, &timer_data->delay_off)) {
101 /* no hardware acceleration, blink via timer */
102 mod_timer(&timer_data->timer, jiffies + 1);
103 }
104 }
105 ret = count;
106 }
107
108 return ret;
109}
110
111static ssize_t led_delay_off_show(struct device *dev,
112 struct device_attribute *attr, char *buf)
113{
114 struct led_classdev *led_cdev = dev_get_drvdata(dev);
115 struct timer_trig_data *timer_data = led_cdev->trigger_data;
116
117 return sprintf(buf, "%lu\n", timer_data->delay_off);
118}
119
120static ssize_t led_delay_off_store(struct device *dev,
121 struct device_attribute *attr, const char *buf, size_t size)
122{
123 struct led_classdev *led_cdev = dev_get_drvdata(dev);
124 struct timer_trig_data *timer_data = led_cdev->trigger_data;
125 int ret = -EINVAL;
126 char *after;
127 unsigned long state = simple_strtoul(buf, &after, 10);
128 size_t count = after - buf;
129
130 if (*after && isspace(*after))
131 count++;
132
133 if (count == size) {
134 if (timer_data->delay_off != state) {
135 /* the new value differs from the previous */
136 timer_data->delay_off = state;
137
138 /* deactivate previous settings */
139 del_timer_sync(&timer_data->timer);
140
141 /* try to activate hardware acceleration, if any */
142 if (!led_cdev->blink_set ||
143 led_cdev->blink_set(led_cdev,
144 &timer_data->delay_on, &timer_data->delay_off)) {
145 /* no hardware acceleration, blink via timer */
146 mod_timer(&timer_data->timer, jiffies + 1);
147 }
148 }
149 ret = count;
150 }
151
152 return ret;
153}
154
155static DEVICE_ATTR(delay_on, 0644, led_delay_on_show, led_delay_on_store);
156static DEVICE_ATTR(delay_off, 0644, led_delay_off_show, led_delay_off_store);
157
158static void timer_trig_activate(struct led_classdev *led_cdev)
159{
160 struct timer_trig_data *timer_data;
161 int rc;
162
163 timer_data = kzalloc(sizeof(struct timer_trig_data), GFP_KERNEL);
164 if (!timer_data)
165 return;
166
167 timer_data->brightness_on = led_get_brightness(led_cdev);
168 if (timer_data->brightness_on == LED_OFF)
169 timer_data->brightness_on = led_cdev->max_brightness;
170 led_cdev->trigger_data = timer_data;
171
172 init_timer(&timer_data->timer);
173 timer_data->timer.function = led_timer_function;
174 timer_data->timer.data = (unsigned long) led_cdev;
175
176 rc = device_create_file(led_cdev->dev, &dev_attr_delay_on);
177 if (rc)
178 goto err_out;
179 rc = device_create_file(led_cdev->dev, &dev_attr_delay_off);
180 if (rc)
181 goto err_out_delayon;
182
183 /* If there is hardware support for blinking, start one
184 * user friendly blink rate chosen by the driver.
185 */
186 if (led_cdev->blink_set)
187 led_cdev->blink_set(led_cdev,
188 &timer_data->delay_on, &timer_data->delay_off);
189
190 return;
191
192err_out_delayon:
193 device_remove_file(led_cdev->dev, &dev_attr_delay_on);
194err_out:
195 led_cdev->trigger_data = NULL;
196 kfree(timer_data);
197}
198
199static void timer_trig_deactivate(struct led_classdev *led_cdev)
200{
201 struct timer_trig_data *timer_data = led_cdev->trigger_data;
202 unsigned long on = 0, off = 0;
203
204 if (timer_data) {
205 device_remove_file(led_cdev->dev, &dev_attr_delay_on);
206 device_remove_file(led_cdev->dev, &dev_attr_delay_off);
207 del_timer_sync(&timer_data->timer);
208 kfree(timer_data);
209 }
210
211 /* If there is hardware support for blinking, stop it */
212 if (led_cdev->blink_set)
213 led_cdev->blink_set(led_cdev, &on, &off);
214}
215
216static struct led_trigger timer_led_trigger = {
217 .name = "timer",
218 .activate = timer_trig_activate,
219 .deactivate = timer_trig_deactivate,
220};
221
222static int __init timer_trig_init(void)
223{
224 return led_trigger_register(&timer_led_trigger);
225}
226
227static void __exit timer_trig_exit(void)
228{
229 led_trigger_unregister(&timer_led_trigger);
230}
231
232module_init(timer_trig_init);
233module_exit(timer_trig_exit);
234
235MODULE_AUTHOR("Richard Purdie <rpurdie@openedhand.com>");
236MODULE_DESCRIPTION("Timer LED trigger");
237MODULE_LICENSE("GPL");