Merge branch 'upstream-linus' of master.kernel.org:/pub/scm/linux/kernel/git/jgarzik...
[linux-2.6] / drivers / video / backlight / backlight.c
1 /*
2  * Backlight Lowlevel Control Abstraction
3  *
4  * Copyright (C) 2003,2004 Hewlett-Packard Company
5  *
6  */
7
8 #include <linux/module.h>
9 #include <linux/init.h>
10 #include <linux/device.h>
11 #include <linux/backlight.h>
12 #include <linux/notifier.h>
13 #include <linux/ctype.h>
14 #include <linux/err.h>
15 #include <linux/fb.h>
16
17 #ifdef CONFIG_PMAC_BACKLIGHT
18 #include <asm/backlight.h>
19 #endif
20
21 #if defined(CONFIG_FB) || (defined(CONFIG_FB_MODULE) && \
22                            defined(CONFIG_BACKLIGHT_CLASS_DEVICE_MODULE))
23 /* This callback gets called when something important happens inside a
24  * framebuffer driver. We're looking if that important event is blanking,
25  * and if it is, we're switching backlight power as well ...
26  */
27 static int fb_notifier_callback(struct notifier_block *self,
28                                 unsigned long event, void *data)
29 {
30         struct backlight_device *bd;
31         struct fb_event *evdata = data;
32
33         /* If we aren't interested in this event, skip it immediately ... */
34         if (event != FB_EVENT_BLANK && event != FB_EVENT_CONBLANK)
35                 return 0;
36
37         bd = container_of(self, struct backlight_device, fb_notif);
38         mutex_lock(&bd->ops_lock);
39         if (bd->ops)
40                 if (!bd->ops->check_fb ||
41                     bd->ops->check_fb(evdata->info)) {
42                         bd->props.fb_blank = *(int *)evdata->data;
43                         backlight_update_status(bd);
44                 }
45         mutex_unlock(&bd->ops_lock);
46         return 0;
47 }
48
49 static int backlight_register_fb(struct backlight_device *bd)
50 {
51         memset(&bd->fb_notif, 0, sizeof(bd->fb_notif));
52         bd->fb_notif.notifier_call = fb_notifier_callback;
53
54         return fb_register_client(&bd->fb_notif);
55 }
56
57 static void backlight_unregister_fb(struct backlight_device *bd)
58 {
59         fb_unregister_client(&bd->fb_notif);
60 }
61 #else
62 static inline int backlight_register_fb(struct backlight_device *bd)
63 {
64         return 0;
65 }
66
67 static inline void backlight_unregister_fb(struct backlight_device *bd)
68 {
69 }
70 #endif /* CONFIG_FB */
71
72 static ssize_t backlight_show_power(struct class_device *cdev, char *buf)
73 {
74         struct backlight_device *bd = to_backlight_device(cdev);
75
76         return sprintf(buf, "%d\n", bd->props.power);
77 }
78
79 static ssize_t backlight_store_power(struct class_device *cdev, const char *buf, size_t count)
80 {
81         int rc = -ENXIO;
82         char *endp;
83         struct backlight_device *bd = to_backlight_device(cdev);
84         int power = simple_strtoul(buf, &endp, 0);
85         size_t size = endp - buf;
86
87         if (*endp && isspace(*endp))
88                 size++;
89         if (size != count)
90                 return -EINVAL;
91
92         mutex_lock(&bd->ops_lock);
93         if (bd->ops) {
94                 pr_debug("backlight: set power to %d\n", power);
95                 bd->props.power = power;
96                 backlight_update_status(bd);
97                 rc = count;
98         }
99         mutex_unlock(&bd->ops_lock);
100
101         return rc;
102 }
103
104 static ssize_t backlight_show_brightness(struct class_device *cdev, char *buf)
105 {
106         struct backlight_device *bd = to_backlight_device(cdev);
107
108         return sprintf(buf, "%d\n", bd->props.brightness);
109 }
110
111 static ssize_t backlight_store_brightness(struct class_device *cdev, const char *buf, size_t count)
112 {
113         int rc = -ENXIO;
114         char *endp;
115         struct backlight_device *bd = to_backlight_device(cdev);
116         int brightness = simple_strtoul(buf, &endp, 0);
117         size_t size = endp - buf;
118
119         if (*endp && isspace(*endp))
120                 size++;
121         if (size != count)
122                 return -EINVAL;
123
124         mutex_lock(&bd->ops_lock);
125         if (bd->ops) {
126                 if (brightness > bd->props.max_brightness)
127                         rc = -EINVAL;
128                 else {
129                         pr_debug("backlight: set brightness to %d\n",
130                                  brightness);
131                         bd->props.brightness = brightness;
132                         backlight_update_status(bd);
133                         rc = count;
134                 }
135         }
136         mutex_unlock(&bd->ops_lock);
137
138         return rc;
139 }
140
141 static ssize_t backlight_show_max_brightness(struct class_device *cdev, char *buf)
142 {
143         struct backlight_device *bd = to_backlight_device(cdev);
144
145         return sprintf(buf, "%d\n", bd->props.max_brightness);
146 }
147
148 static ssize_t backlight_show_actual_brightness(struct class_device *cdev,
149                                                 char *buf)
150 {
151         int rc = -ENXIO;
152         struct backlight_device *bd = to_backlight_device(cdev);
153
154         mutex_lock(&bd->ops_lock);
155         if (bd->ops && bd->ops->get_brightness)
156                 rc = sprintf(buf, "%d\n", bd->ops->get_brightness(bd));
157         mutex_unlock(&bd->ops_lock);
158
159         return rc;
160 }
161
162 static void backlight_class_release(struct class_device *dev)
163 {
164         struct backlight_device *bd = to_backlight_device(dev);
165         kfree(bd);
166 }
167
168 static struct class backlight_class = {
169         .name = "backlight",
170         .release = backlight_class_release,
171 };
172
173 #define DECLARE_ATTR(_name,_mode,_show,_store)                  \
174 {                                                               \
175         .attr   = { .name = __stringify(_name), .mode = _mode, .owner = THIS_MODULE },  \
176         .show   = _show,                                        \
177         .store  = _store,                                       \
178 }
179
180 static const struct class_device_attribute bl_class_device_attributes[] = {
181         DECLARE_ATTR(power, 0644, backlight_show_power, backlight_store_power),
182         DECLARE_ATTR(brightness, 0644, backlight_show_brightness,
183                      backlight_store_brightness),
184         DECLARE_ATTR(actual_brightness, 0444, backlight_show_actual_brightness,
185                      NULL),
186         DECLARE_ATTR(max_brightness, 0444, backlight_show_max_brightness, NULL),
187 };
188
189 /**
190  * backlight_device_register - create and register a new object of
191  *   backlight_device class.
192  * @name: the name of the new object(must be the same as the name of the
193  *   respective framebuffer device).
194  * @devdata: an optional pointer to be stored in the class_device. The
195  *   methods may retrieve it by using class_get_devdata(&bd->class_dev).
196  * @ops: the backlight operations structure.
197  *
198  * Creates and registers new backlight class_device. Returns either an
199  * ERR_PTR() or a pointer to the newly allocated device.
200  */
201 struct backlight_device *backlight_device_register(const char *name,
202         struct device *dev,
203         void *devdata,
204         struct backlight_ops *ops)
205 {
206         int i, rc;
207         struct backlight_device *new_bd;
208
209         pr_debug("backlight_device_alloc: name=%s\n", name);
210
211         new_bd = kzalloc(sizeof(struct backlight_device), GFP_KERNEL);
212         if (!new_bd)
213                 return ERR_PTR(-ENOMEM);
214
215         mutex_init(&new_bd->update_lock);
216         mutex_init(&new_bd->ops_lock);
217         new_bd->ops = ops;
218         new_bd->class_dev.class = &backlight_class;
219         new_bd->class_dev.dev = dev;
220         strlcpy(new_bd->class_dev.class_id, name, KOBJ_NAME_LEN);
221         class_set_devdata(&new_bd->class_dev, devdata);
222
223         rc = class_device_register(&new_bd->class_dev);
224         if (rc) {
225                 kfree(new_bd);
226                 return ERR_PTR(rc);
227         }
228
229         rc = backlight_register_fb(new_bd);
230         if (rc) {
231                 class_device_unregister(&new_bd->class_dev);
232                 return ERR_PTR(rc);
233         }
234
235
236         for (i = 0; i < ARRAY_SIZE(bl_class_device_attributes); i++) {
237                 rc = class_device_create_file(&new_bd->class_dev,
238                                               &bl_class_device_attributes[i]);
239                 if (rc) {
240                         while (--i >= 0)
241                                 class_device_remove_file(&new_bd->class_dev,
242                                                          &bl_class_device_attributes[i]);
243                         class_device_unregister(&new_bd->class_dev);
244                         /* No need to kfree(new_bd) since release() method was called */
245                         return ERR_PTR(rc);
246                 }
247         }
248
249 #ifdef CONFIG_PMAC_BACKLIGHT
250         mutex_lock(&pmac_backlight_mutex);
251         if (!pmac_backlight)
252                 pmac_backlight = new_bd;
253         mutex_unlock(&pmac_backlight_mutex);
254 #endif
255
256         return new_bd;
257 }
258 EXPORT_SYMBOL(backlight_device_register);
259
260 /**
261  * backlight_device_unregister - unregisters a backlight device object.
262  * @bd: the backlight device object to be unregistered and freed.
263  *
264  * Unregisters a previously registered via backlight_device_register object.
265  */
266 void backlight_device_unregister(struct backlight_device *bd)
267 {
268         int i;
269
270         if (!bd)
271                 return;
272
273         pr_debug("backlight_device_unregister: name=%s\n", bd->class_dev.class_id);
274
275 #ifdef CONFIG_PMAC_BACKLIGHT
276         mutex_lock(&pmac_backlight_mutex);
277         if (pmac_backlight == bd)
278                 pmac_backlight = NULL;
279         mutex_unlock(&pmac_backlight_mutex);
280 #endif
281
282         for (i = 0; i < ARRAY_SIZE(bl_class_device_attributes); i++)
283                 class_device_remove_file(&bd->class_dev,
284                                          &bl_class_device_attributes[i]);
285
286         mutex_lock(&bd->ops_lock);
287         bd->ops = NULL;
288         mutex_unlock(&bd->ops_lock);
289
290         backlight_unregister_fb(bd);
291
292         class_device_unregister(&bd->class_dev);
293 }
294 EXPORT_SYMBOL(backlight_device_unregister);
295
296 static void __exit backlight_class_exit(void)
297 {
298         class_unregister(&backlight_class);
299 }
300
301 static int __init backlight_class_init(void)
302 {
303         return class_register(&backlight_class);
304 }
305
306 /*
307  * if this is compiled into the kernel, we need to ensure that the
308  * class is registered before users of the class try to register lcd's
309  */
310 postcore_initcall(backlight_class_init);
311 module_exit(backlight_class_exit);
312
313 MODULE_LICENSE("GPL");
314 MODULE_AUTHOR("Jamey Hicks <jamey.hicks@hp.com>, Andrew Zabolotny <zap@homelink.ru>");
315 MODULE_DESCRIPTION("Backlight Lowlevel Control Abstraction");