Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394...
[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                         if (bd->props.fb_blank == FB_BLANK_UNBLANK)
44                                 bd->props.state &= ~BL_CORE_FBBLANK;
45                         else
46                                 bd->props.state |= BL_CORE_FBBLANK;
47                         backlight_update_status(bd);
48                 }
49         mutex_unlock(&bd->ops_lock);
50         return 0;
51 }
52
53 static int backlight_register_fb(struct backlight_device *bd)
54 {
55         memset(&bd->fb_notif, 0, sizeof(bd->fb_notif));
56         bd->fb_notif.notifier_call = fb_notifier_callback;
57
58         return fb_register_client(&bd->fb_notif);
59 }
60
61 static void backlight_unregister_fb(struct backlight_device *bd)
62 {
63         fb_unregister_client(&bd->fb_notif);
64 }
65 #else
66 static inline int backlight_register_fb(struct backlight_device *bd)
67 {
68         return 0;
69 }
70
71 static inline void backlight_unregister_fb(struct backlight_device *bd)
72 {
73 }
74 #endif /* CONFIG_FB */
75
76 static ssize_t backlight_show_power(struct device *dev,
77                 struct device_attribute *attr,char *buf)
78 {
79         struct backlight_device *bd = to_backlight_device(dev);
80
81         return sprintf(buf, "%d\n", bd->props.power);
82 }
83
84 static ssize_t backlight_store_power(struct device *dev,
85                 struct device_attribute *attr, const char *buf, size_t count)
86 {
87         int rc;
88         struct backlight_device *bd = to_backlight_device(dev);
89         unsigned long power;
90
91         rc = strict_strtoul(buf, 0, &power);
92         if (rc)
93                 return rc;
94
95         rc = -ENXIO;
96         mutex_lock(&bd->ops_lock);
97         if (bd->ops) {
98                 pr_debug("backlight: set power to %lu\n", power);
99                 if (bd->props.power != power) {
100                         bd->props.power = power;
101                         backlight_update_status(bd);
102                 }
103                 rc = count;
104         }
105         mutex_unlock(&bd->ops_lock);
106
107         return rc;
108 }
109
110 static ssize_t backlight_show_brightness(struct device *dev,
111                 struct device_attribute *attr, char *buf)
112 {
113         struct backlight_device *bd = to_backlight_device(dev);
114
115         return sprintf(buf, "%d\n", bd->props.brightness);
116 }
117
118 static ssize_t backlight_store_brightness(struct device *dev,
119                 struct device_attribute *attr, const char *buf, size_t count)
120 {
121         int rc;
122         struct backlight_device *bd = to_backlight_device(dev);
123         unsigned long brightness;
124
125         rc = strict_strtoul(buf, 0, &brightness);
126         if (rc)
127                 return rc;
128
129         rc = -ENXIO;
130
131         mutex_lock(&bd->ops_lock);
132         if (bd->ops) {
133                 if (brightness > bd->props.max_brightness)
134                         rc = -EINVAL;
135                 else {
136                         pr_debug("backlight: set brightness to %lu\n",
137                                  brightness);
138                         bd->props.brightness = brightness;
139                         backlight_update_status(bd);
140                         rc = count;
141                 }
142         }
143         mutex_unlock(&bd->ops_lock);
144
145         return rc;
146 }
147
148 static ssize_t backlight_show_max_brightness(struct device *dev,
149                 struct device_attribute *attr, char *buf)
150 {
151         struct backlight_device *bd = to_backlight_device(dev);
152
153         return sprintf(buf, "%d\n", bd->props.max_brightness);
154 }
155
156 static ssize_t backlight_show_actual_brightness(struct device *dev,
157                 struct device_attribute *attr, char *buf)
158 {
159         int rc = -ENXIO;
160         struct backlight_device *bd = to_backlight_device(dev);
161
162         mutex_lock(&bd->ops_lock);
163         if (bd->ops && bd->ops->get_brightness)
164                 rc = sprintf(buf, "%d\n", bd->ops->get_brightness(bd));
165         mutex_unlock(&bd->ops_lock);
166
167         return rc;
168 }
169
170 static struct class *backlight_class;
171
172 static int backlight_suspend(struct device *dev, pm_message_t state)
173 {
174         struct backlight_device *bd = to_backlight_device(dev);
175
176         if (bd->ops->options & BL_CORE_SUSPENDRESUME) {
177                 mutex_lock(&bd->ops_lock);
178                 bd->props.state |= BL_CORE_SUSPENDED;
179                 backlight_update_status(bd);
180                 mutex_unlock(&bd->ops_lock);
181         }
182
183         return 0;
184 }
185
186 static int backlight_resume(struct device *dev)
187 {
188         struct backlight_device *bd = to_backlight_device(dev);
189
190         if (bd->ops->options & BL_CORE_SUSPENDRESUME) {
191                 mutex_lock(&bd->ops_lock);
192                 bd->props.state &= ~BL_CORE_SUSPENDED;
193                 backlight_update_status(bd);
194                 mutex_unlock(&bd->ops_lock);
195         }
196
197         return 0;
198 }
199
200 static void bl_device_release(struct device *dev)
201 {
202         struct backlight_device *bd = to_backlight_device(dev);
203         kfree(bd);
204 }
205
206 static struct device_attribute bl_device_attributes[] = {
207         __ATTR(bl_power, 0644, backlight_show_power, backlight_store_power),
208         __ATTR(brightness, 0644, backlight_show_brightness,
209                      backlight_store_brightness),
210         __ATTR(actual_brightness, 0444, backlight_show_actual_brightness,
211                      NULL),
212         __ATTR(max_brightness, 0444, backlight_show_max_brightness, NULL),
213         __ATTR_NULL,
214 };
215
216 /**
217  * backlight_device_register - create and register a new object of
218  *   backlight_device class.
219  * @name: the name of the new object(must be the same as the name of the
220  *   respective framebuffer device).
221  * @parent: a pointer to the parent device
222  * @devdata: an optional pointer to be stored for private driver use. The
223  *   methods may retrieve it by using bl_get_data(bd).
224  * @ops: the backlight operations structure.
225  *
226  * Creates and registers new backlight device. Returns either an
227  * ERR_PTR() or a pointer to the newly allocated device.
228  */
229 struct backlight_device *backlight_device_register(const char *name,
230                 struct device *parent, void *devdata, struct backlight_ops *ops)
231 {
232         struct backlight_device *new_bd;
233         int rc;
234
235         pr_debug("backlight_device_register: name=%s\n", name);
236
237         new_bd = kzalloc(sizeof(struct backlight_device), GFP_KERNEL);
238         if (!new_bd)
239                 return ERR_PTR(-ENOMEM);
240
241         mutex_init(&new_bd->update_lock);
242         mutex_init(&new_bd->ops_lock);
243
244         new_bd->dev.class = backlight_class;
245         new_bd->dev.parent = parent;
246         new_bd->dev.release = bl_device_release;
247         dev_set_name(&new_bd->dev, name);
248         dev_set_drvdata(&new_bd->dev, devdata);
249
250         rc = device_register(&new_bd->dev);
251         if (rc) {
252                 kfree(new_bd);
253                 return ERR_PTR(rc);
254         }
255
256         rc = backlight_register_fb(new_bd);
257         if (rc) {
258                 device_unregister(&new_bd->dev);
259                 return ERR_PTR(rc);
260         }
261
262         new_bd->ops = ops;
263
264 #ifdef CONFIG_PMAC_BACKLIGHT
265         mutex_lock(&pmac_backlight_mutex);
266         if (!pmac_backlight)
267                 pmac_backlight = new_bd;
268         mutex_unlock(&pmac_backlight_mutex);
269 #endif
270
271         return new_bd;
272 }
273 EXPORT_SYMBOL(backlight_device_register);
274
275 /**
276  * backlight_device_unregister - unregisters a backlight device object.
277  * @bd: the backlight device object to be unregistered and freed.
278  *
279  * Unregisters a previously registered via backlight_device_register object.
280  */
281 void backlight_device_unregister(struct backlight_device *bd)
282 {
283         if (!bd)
284                 return;
285
286 #ifdef CONFIG_PMAC_BACKLIGHT
287         mutex_lock(&pmac_backlight_mutex);
288         if (pmac_backlight == bd)
289                 pmac_backlight = NULL;
290         mutex_unlock(&pmac_backlight_mutex);
291 #endif
292         mutex_lock(&bd->ops_lock);
293         bd->ops = NULL;
294         mutex_unlock(&bd->ops_lock);
295
296         backlight_unregister_fb(bd);
297         device_unregister(&bd->dev);
298 }
299 EXPORT_SYMBOL(backlight_device_unregister);
300
301 static void __exit backlight_class_exit(void)
302 {
303         class_destroy(backlight_class);
304 }
305
306 static int __init backlight_class_init(void)
307 {
308         backlight_class = class_create(THIS_MODULE, "backlight");
309         if (IS_ERR(backlight_class)) {
310                 printk(KERN_WARNING "Unable to create backlight class; errno = %ld\n",
311                                 PTR_ERR(backlight_class));
312                 return PTR_ERR(backlight_class);
313         }
314
315         backlight_class->dev_attrs = bl_device_attributes;
316         backlight_class->suspend = backlight_suspend;
317         backlight_class->resume = backlight_resume;
318         return 0;
319 }
320
321 /*
322  * if this is compiled into the kernel, we need to ensure that the
323  * class is registered before users of the class try to register lcd's
324  */
325 postcore_initcall(backlight_class_init);
326 module_exit(backlight_class_exit);
327
328 MODULE_LICENSE("GPL");
329 MODULE_AUTHOR("Jamey Hicks <jamey.hicks@hp.com>, Andrew Zabolotny <zap@homelink.ru>");
330 MODULE_DESCRIPTION("Backlight Lowlevel Control Abstraction");