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path: root/drivers/video/backlight/backlight.c
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Diffstat (limited to 'drivers/video/backlight/backlight.c')
-rw-r--r--drivers/video/backlight/backlight.c264
1 files changed, 264 insertions, 0 deletions
diff --git a/drivers/video/backlight/backlight.c b/drivers/video/backlight/backlight.c
new file mode 100644
index 000000000000..acc81cb01d56
--- /dev/null
+++ b/drivers/video/backlight/backlight.c
@@ -0,0 +1,264 @@
1/*
2 * Backlight Lowlevel Control Abstraction
3 *
4 * Copyright (C) 2003,2004 Hewlett-Packard Company
5 *
6 */
7
8#include <linux/version.h>
9#include <linux/module.h>
10#include <linux/init.h>
11#include <linux/device.h>
12#include <linux/backlight.h>
13#include <linux/notifier.h>
14#include <linux/ctype.h>
15#include <linux/err.h>
16#include <linux/fb.h>
17#include <asm/bug.h>
18
19static ssize_t backlight_show_power(struct class_device *cdev, char *buf)
20{
21 int rc;
22 struct backlight_device *bd = to_backlight_device(cdev);
23
24 down(&bd->sem);
25 if (likely(bd->props && bd->props->get_power))
26 rc = sprintf(buf, "%d\n", bd->props->get_power(bd));
27 else
28 rc = -ENXIO;
29 up(&bd->sem);
30
31 return rc;
32}
33
34static ssize_t backlight_store_power(struct class_device *cdev, const char *buf, size_t count)
35{
36 int rc, power;
37 char *endp;
38 struct backlight_device *bd = to_backlight_device(cdev);
39
40 power = simple_strtoul(buf, &endp, 0);
41 if (*endp && !isspace(*endp))
42 return -EINVAL;
43
44 down(&bd->sem);
45 if (likely(bd->props && bd->props->set_power)) {
46 pr_debug("backlight: set power to %d\n", power);
47 bd->props->set_power(bd, power);
48 rc = count;
49 } else
50 rc = -ENXIO;
51 up(&bd->sem);
52
53 return rc;
54}
55
56static ssize_t backlight_show_brightness(struct class_device *cdev, char *buf)
57{
58 int rc;
59 struct backlight_device *bd = to_backlight_device(cdev);
60
61 down(&bd->sem);
62 if (likely(bd->props && bd->props->get_brightness))
63 rc = sprintf(buf, "%d\n", bd->props->get_brightness(bd));
64 else
65 rc = -ENXIO;
66 up(&bd->sem);
67
68 return rc;
69}
70
71static ssize_t backlight_store_brightness(struct class_device *cdev, const char *buf, size_t count)
72{
73 int rc, brightness;
74 char *endp;
75 struct backlight_device *bd = to_backlight_device(cdev);
76
77 brightness = simple_strtoul(buf, &endp, 0);
78 if (*endp && !isspace(*endp))
79 return -EINVAL;
80
81 down(&bd->sem);
82 if (likely(bd->props && bd->props->set_brightness)) {
83 pr_debug("backlight: set brightness to %d\n", brightness);
84 bd->props->set_brightness(bd, brightness);
85 rc = count;
86 } else
87 rc = -ENXIO;
88 up(&bd->sem);
89
90 return rc;
91}
92
93static ssize_t backlight_show_max_brightness(struct class_device *cdev, char *buf)
94{
95 int rc;
96 struct backlight_device *bd = to_backlight_device(cdev);
97
98 down(&bd->sem);
99 if (likely(bd->props))
100 rc = sprintf(buf, "%d\n", bd->props->max_brightness);
101 else
102 rc = -ENXIO;
103 up(&bd->sem);
104
105 return rc;
106}
107
108static void backlight_class_release(struct class_device *dev)
109{
110 struct backlight_device *bd = to_backlight_device(dev);
111 kfree(bd);
112}
113
114static struct class backlight_class = {
115 .name = "backlight",
116 .release = backlight_class_release,
117};
118
119#define DECLARE_ATTR(_name,_mode,_show,_store) \
120{ \
121 .attr = { .name = __stringify(_name), .mode = _mode, .owner = THIS_MODULE }, \
122 .show = _show, \
123 .store = _store, \
124}
125
126static struct class_device_attribute bl_class_device_attributes[] = {
127 DECLARE_ATTR(power, 0644, backlight_show_power, backlight_store_power),
128 DECLARE_ATTR(brightness, 0644, backlight_show_brightness, backlight_store_brightness),
129 DECLARE_ATTR(max_brightness, 0444, backlight_show_max_brightness, NULL),
130};
131
132/* This callback gets called when something important happens inside a
133 * framebuffer driver. We're looking if that important event is blanking,
134 * and if it is, we're switching backlight power as well ...
135 */
136static int fb_notifier_callback(struct notifier_block *self,
137 unsigned long event, void *data)
138{
139 struct backlight_device *bd;
140 struct fb_event *evdata =(struct fb_event *)data;
141
142 /* If we aren't interested in this event, skip it immediately ... */
143 if (event != FB_EVENT_BLANK)
144 return 0;
145
146 bd = container_of(self, struct backlight_device, fb_notif);
147 down(&bd->sem);
148 if (bd->props)
149 if (!bd->props->check_fb || bd->props->check_fb(evdata->info))
150 bd->props->set_power(bd, *(int *)evdata->data);
151 up(&bd->sem);
152 return 0;
153}
154
155/**
156 * backlight_device_register - create and register a new object of
157 * backlight_device class.
158 * @name: the name of the new object(must be the same as the name of the
159 * respective framebuffer device).
160 * @devdata: an optional pointer to be stored in the class_device. The
161 * methods may retrieve it by using class_get_devdata(&bd->class_dev).
162 * @bp: the backlight properties structure.
163 *
164 * Creates and registers new backlight class_device. Returns either an
165 * ERR_PTR() or a pointer to the newly allocated device.
166 */
167struct backlight_device *backlight_device_register(const char *name, void *devdata,
168 struct backlight_properties *bp)
169{
170 int i, rc;
171 struct backlight_device *new_bd;
172
173 pr_debug("backlight_device_alloc: name=%s\n", name);
174
175 new_bd = kmalloc(sizeof(struct backlight_device), GFP_KERNEL);
176 if (unlikely(!new_bd))
177 return ERR_PTR(ENOMEM);
178
179 init_MUTEX(&new_bd->sem);
180 new_bd->props = bp;
181 memset(&new_bd->class_dev, 0, sizeof(new_bd->class_dev));
182 new_bd->class_dev.class = &backlight_class;
183 strlcpy(new_bd->class_dev.class_id, name, KOBJ_NAME_LEN);
184 class_set_devdata(&new_bd->class_dev, devdata);
185
186 rc = class_device_register(&new_bd->class_dev);
187 if (unlikely(rc)) {
188error: kfree(new_bd);
189 return ERR_PTR(rc);
190 }
191
192 memset(&new_bd->fb_notif, 0, sizeof(new_bd->fb_notif));
193 new_bd->fb_notif.notifier_call = fb_notifier_callback;
194
195 rc = fb_register_client(&new_bd->fb_notif);
196 if (unlikely(rc))
197 goto error;
198
199 for (i = 0; i < ARRAY_SIZE(bl_class_device_attributes); i++) {
200 rc = class_device_create_file(&new_bd->class_dev,
201 &bl_class_device_attributes[i]);
202 if (unlikely(rc)) {
203 while (--i >= 0)
204 class_device_remove_file(&new_bd->class_dev,
205 &bl_class_device_attributes[i]);
206 class_device_unregister(&new_bd->class_dev);
207 /* No need to kfree(new_bd) since release() method was called */
208 return ERR_PTR(rc);
209 }
210 }
211
212 return new_bd;
213}
214EXPORT_SYMBOL(backlight_device_register);
215
216/**
217 * backlight_device_unregister - unregisters a backlight device object.
218 * @bd: the backlight device object to be unregistered and freed.
219 *
220 * Unregisters a previously registered via backlight_device_register object.
221 */
222void backlight_device_unregister(struct backlight_device *bd)
223{
224 int i;
225
226 if (!bd)
227 return;
228
229 pr_debug("backlight_device_unregister: name=%s\n", bd->class_dev.class_id);
230
231 for (i = 0; i < ARRAY_SIZE(bl_class_device_attributes); i++)
232 class_device_remove_file(&bd->class_dev,
233 &bl_class_device_attributes[i]);
234
235 down(&bd->sem);
236 bd->props = NULL;
237 up(&bd->sem);
238
239 fb_unregister_client(&bd->fb_notif);
240
241 class_device_unregister(&bd->class_dev);
242}
243EXPORT_SYMBOL(backlight_device_unregister);
244
245static void __exit backlight_class_exit(void)
246{
247 class_unregister(&backlight_class);
248}
249
250static int __init backlight_class_init(void)
251{
252 return class_register(&backlight_class);
253}
254
255/*
256 * if this is compiled into the kernel, we need to ensure that the
257 * class is registered before users of the class try to register lcd's
258 */
259postcore_initcall(backlight_class_init);
260module_exit(backlight_class_exit);
261
262MODULE_LICENSE("GPL");
263MODULE_AUTHOR("Jamey Hicks <jamey.hicks@hp.com>, Andrew Zabolotny <zap@homelink.ru>");
264MODULE_DESCRIPTION("Backlight Lowlevel Control Abstraction");