leds: Add support for hardware accelerated LED flashing
[linux-2.6.git] / drivers / leds / ledtrig-timer.c
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
27 struct timer_trig_data {
28         unsigned long delay_on;         /* milliseconds on */
29         unsigned long delay_off;        /* milliseconds off */
30         struct timer_list timer;
31 };
32
33 static void led_timer_function(unsigned long data)
34 {
35         struct led_classdev *led_cdev = (struct led_classdev *) data;
36         struct timer_trig_data *timer_data = led_cdev->trigger_data;
37         unsigned long brightness = LED_OFF;
38         unsigned long delay = timer_data->delay_off;
39
40         if (!timer_data->delay_on || !timer_data->delay_off) {
41                 led_set_brightness(led_cdev, LED_OFF);
42                 return;
43         }
44
45         if (!led_cdev->brightness) {
46                 brightness = LED_FULL;
47                 delay = timer_data->delay_on;
48         }
49
50         led_set_brightness(led_cdev, brightness);
51
52         mod_timer(&timer_data->timer, jiffies + msecs_to_jiffies(delay));
53 }
54
55 static ssize_t led_delay_on_show(struct device *dev, 
56                 struct device_attribute *attr, char *buf)
57 {
58         struct led_classdev *led_cdev = dev_get_drvdata(dev);
59         struct timer_trig_data *timer_data = led_cdev->trigger_data;
60
61         sprintf(buf, "%lu\n", timer_data->delay_on);
62
63         return strlen(buf) + 1;
64 }
65
66 static ssize_t led_delay_on_store(struct device *dev, 
67                 struct device_attribute *attr, const char *buf, size_t size)
68 {
69         struct led_classdev *led_cdev = dev_get_drvdata(dev);
70         struct timer_trig_data *timer_data = led_cdev->trigger_data;
71         int ret = -EINVAL;
72         char *after;
73         unsigned long state = simple_strtoul(buf, &after, 10);
74         size_t count = after - buf;
75
76         if (*after && isspace(*after))
77                 count++;
78
79         if (count == size) {
80                 if (timer_data->delay_on != state) {
81                         /* the new value differs from the previous */
82                         timer_data->delay_on = state;
83
84                         /* deactivate previous settings */
85                         del_timer_sync(&timer_data->timer);
86
87                         /* try to activate hardware acceleration, if any */
88                         if (!led_cdev->blink_set ||
89                             led_cdev->blink_set(led_cdev,
90                                 &timer_data->delay_on, &timer_data->delay_off)) {
91                                 /* no hardware acceleration, blink via timer */
92                                 mod_timer(&timer_data->timer, jiffies + 1);
93                         }
94                 }
95                 ret = count;
96         }
97
98         return ret;
99 }
100
101 static ssize_t led_delay_off_show(struct device *dev, 
102                 struct device_attribute *attr, char *buf)
103 {
104         struct led_classdev *led_cdev = dev_get_drvdata(dev);
105         struct timer_trig_data *timer_data = led_cdev->trigger_data;
106
107         sprintf(buf, "%lu\n", timer_data->delay_off);
108
109         return strlen(buf) + 1;
110 }
111
112 static ssize_t led_delay_off_store(struct device *dev, 
113                 struct device_attribute *attr, const char *buf, size_t size)
114 {
115         struct led_classdev *led_cdev = dev_get_drvdata(dev);
116         struct timer_trig_data *timer_data = led_cdev->trigger_data;
117         int ret = -EINVAL;
118         char *after;
119         unsigned long state = simple_strtoul(buf, &after, 10);
120         size_t count = after - buf;
121
122         if (*after && isspace(*after))
123                 count++;
124
125         if (count == size) {
126                 if (timer_data->delay_off != state) {
127                         /* the new value differs from the previous */
128                         timer_data->delay_off = state;
129
130                         /* deactivate previous settings */
131                         del_timer_sync(&timer_data->timer);
132
133                         /* try to activate hardware acceleration, if any */
134                         if (!led_cdev->blink_set ||
135                             led_cdev->blink_set(led_cdev,
136                                 &timer_data->delay_on, &timer_data->delay_off)) {
137                                 /* no hardware acceleration, blink via timer */
138                                 mod_timer(&timer_data->timer, jiffies + 1);
139                         }
140                 }
141                 ret = count;
142         }
143
144         return ret;
145 }
146
147 static DEVICE_ATTR(delay_on, 0644, led_delay_on_show, led_delay_on_store);
148 static DEVICE_ATTR(delay_off, 0644, led_delay_off_show, led_delay_off_store);
149
150 static void timer_trig_activate(struct led_classdev *led_cdev)
151 {
152         struct timer_trig_data *timer_data;
153         int rc;
154
155         timer_data = kzalloc(sizeof(struct timer_trig_data), GFP_KERNEL);
156         if (!timer_data)
157                 return;
158
159         led_cdev->trigger_data = timer_data;
160
161         init_timer(&timer_data->timer);
162         timer_data->timer.function = led_timer_function;
163         timer_data->timer.data = (unsigned long) led_cdev;
164
165         rc = device_create_file(led_cdev->dev, &dev_attr_delay_on);
166         if (rc)
167                 goto err_out;
168         rc = device_create_file(led_cdev->dev, &dev_attr_delay_off);
169         if (rc)
170                 goto err_out_delayon;
171
172         /* If there is hardware support for blinking, start one
173          * user friendly blink rate chosen by the driver.
174          */
175         if (led_cdev->blink_set)
176                 led_cdev->blink_set(led_cdev,
177                         &timer_data->delay_on, &timer_data->delay_off);
178
179         return;
180
181 err_out_delayon:
182         device_remove_file(led_cdev->dev, &dev_attr_delay_on);
183 err_out:
184         led_cdev->trigger_data = NULL;
185         kfree(timer_data);
186 }
187
188 static void timer_trig_deactivate(struct led_classdev *led_cdev)
189 {
190         struct timer_trig_data *timer_data = led_cdev->trigger_data;
191
192         if (timer_data) {
193                 device_remove_file(led_cdev->dev, &dev_attr_delay_on);
194                 device_remove_file(led_cdev->dev, &dev_attr_delay_off);
195                 del_timer_sync(&timer_data->timer);
196                 kfree(timer_data);
197         }
198 }
199
200 static struct led_trigger timer_led_trigger = {
201         .name     = "timer",
202         .activate = timer_trig_activate,
203         .deactivate = timer_trig_deactivate,
204 };
205
206 static int __init timer_trig_init(void)
207 {
208         return led_trigger_register(&timer_led_trigger);
209 }
210
211 static void __exit timer_trig_exit(void)
212 {
213         led_trigger_unregister(&timer_led_trigger);
214 }
215
216 module_init(timer_trig_init);
217 module_exit(timer_trig_exit);
218
219 MODULE_AUTHOR("Richard Purdie <rpurdie@openedhand.com>");
220 MODULE_DESCRIPTION("Timer LED trigger");
221 MODULE_LICENSE("GPL");