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authorRichard Purdie <rpurdie@rpsys.net>2006-03-31 05:31:04 -0500
committerLinus Torvalds <torvalds@g5.osdl.org>2006-03-31 15:18:56 -0500
commitc72a1d608dd0eb3d553a08bfdf1c0041bebaa8a0 (patch)
tree56715f0e0af8a9c33725f3db2f14cf7f870ad46d /drivers/leds/led-class.c
parent75c1d31d9ea71025b73430c696b727e8aa15872d (diff)
[PATCH] LED: add LED class
Add the foundations of a new LEDs subsystem. This patch adds a class which presents LED devices within sysfs and allows their brightness to be controlled. Signed-off-by: Richard Purdie <rpurdie@rpsys.net> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'drivers/leds/led-class.c')
-rw-r--r--drivers/leds/led-class.c147
1 files changed, 147 insertions, 0 deletions
diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c
new file mode 100644
index 000000000000..0292df4101ba
--- /dev/null
+++ b/drivers/leds/led-class.c
@@ -0,0 +1,147 @@
1/*
2 * LED Class Core
3 *
4 * Copyright (C) 2005 John Lenz <lenz@cs.wisc.edu>
5 * Copyright (C) 2005-2006 Richard Purdie <rpurdie@openedhand.com>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 */
11
12#include <linux/config.h>
13#include <linux/module.h>
14#include <linux/kernel.h>
15#include <linux/init.h>
16#include <linux/list.h>
17#include <linux/spinlock.h>
18#include <linux/device.h>
19#include <linux/sysdev.h>
20#include <linux/timer.h>
21#include <linux/err.h>
22#include <linux/leds.h>
23#include "leds.h"
24
25static struct class *leds_class;
26
27static ssize_t led_brightness_show(struct class_device *dev, char *buf)
28{
29 struct led_classdev *led_cdev = class_get_devdata(dev);
30 ssize_t ret = 0;
31
32 /* no lock needed for this */
33 sprintf(buf, "%u\n", led_cdev->brightness);
34 ret = strlen(buf) + 1;
35
36 return ret;
37}
38
39static ssize_t led_brightness_store(struct class_device *dev,
40 const char *buf, size_t size)
41{
42 struct led_classdev *led_cdev = class_get_devdata(dev);
43 ssize_t ret = -EINVAL;
44 char *after;
45 unsigned long state = simple_strtoul(buf, &after, 10);
46
47 if (after - buf > 0) {
48 ret = after - buf;
49 led_set_brightness(led_cdev, state);
50 }
51
52 return ret;
53}
54
55static CLASS_DEVICE_ATTR(brightness, 0644, led_brightness_show,
56 led_brightness_store);
57
58/**
59 * led_classdev_suspend - suspend an led_classdev.
60 * @led_cdev: the led_classdev to suspend.
61 */
62void led_classdev_suspend(struct led_classdev *led_cdev)
63{
64 led_cdev->flags |= LED_SUSPENDED;
65 led_cdev->brightness_set(led_cdev, 0);
66}
67EXPORT_SYMBOL_GPL(led_classdev_suspend);
68
69/**
70 * led_classdev_resume - resume an led_classdev.
71 * @led_cdev: the led_classdev to resume.
72 */
73void led_classdev_resume(struct led_classdev *led_cdev)
74{
75 led_cdev->brightness_set(led_cdev, led_cdev->brightness);
76 led_cdev->flags &= ~LED_SUSPENDED;
77}
78EXPORT_SYMBOL_GPL(led_classdev_resume);
79
80/**
81 * led_classdev_register - register a new object of led_classdev class.
82 * @dev: The device to register.
83 * @led_cdev: the led_classdev structure for this device.
84 */
85int led_classdev_register(struct device *parent, struct led_classdev *led_cdev)
86{
87 led_cdev->class_dev = class_device_create(leds_class, NULL, 0,
88 parent, "%s", led_cdev->name);
89 if (unlikely(IS_ERR(led_cdev->class_dev)))
90 return PTR_ERR(led_cdev->class_dev);
91
92 class_set_devdata(led_cdev->class_dev, led_cdev);
93
94 /* register the attributes */
95 class_device_create_file(led_cdev->class_dev,
96 &class_device_attr_brightness);
97
98 /* add to the list of leds */
99 write_lock(&leds_list_lock);
100 list_add_tail(&led_cdev->node, &leds_list);
101 write_unlock(&leds_list_lock);
102
103 printk(KERN_INFO "Registered led device: %s\n",
104 led_cdev->class_dev->class_id);
105
106 return 0;
107}
108EXPORT_SYMBOL_GPL(led_classdev_register);
109
110/**
111 * led_classdev_unregister - unregisters a object of led_properties class.
112 * @led_cdev: the led device to unreigister
113 *
114 * Unregisters a previously registered via led_classdev_register object.
115 */
116void led_classdev_unregister(struct led_classdev *led_cdev)
117{
118 class_device_remove_file(led_cdev->class_dev,
119 &class_device_attr_brightness);
120
121 class_device_unregister(led_cdev->class_dev);
122
123 write_lock(&leds_list_lock);
124 list_del(&led_cdev->node);
125 write_unlock(&leds_list_lock);
126}
127EXPORT_SYMBOL_GPL(led_classdev_unregister);
128
129static int __init leds_init(void)
130{
131 leds_class = class_create(THIS_MODULE, "leds");
132 if (IS_ERR(leds_class))
133 return PTR_ERR(leds_class);
134 return 0;
135}
136
137static void __exit leds_exit(void)
138{
139 class_destroy(leds_class);
140}
141
142subsys_initcall(leds_init);
143module_exit(leds_exit);
144
145MODULE_AUTHOR("John Lenz, Richard Purdie");
146MODULE_LICENSE("GPL");
147MODULE_DESCRIPTION("LED Class Interface");