7363c1b169e8f5719e5ba9bc1dee3542de468169
[~shefty/rdma-dev.git] / 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 #include <linux/slab.h>
17
18 #ifdef CONFIG_PMAC_BACKLIGHT
19 #include <asm/backlight.h>
20 #endif
21
22 static const char *const backlight_types[] = {
23         [BACKLIGHT_RAW] = "raw",
24         [BACKLIGHT_PLATFORM] = "platform",
25         [BACKLIGHT_FIRMWARE] = "firmware",
26 };
27
28 #if defined(CONFIG_FB) || (defined(CONFIG_FB_MODULE) && \
29                            defined(CONFIG_BACKLIGHT_CLASS_DEVICE_MODULE))
30 /* This callback gets called when something important happens inside a
31  * framebuffer driver. We're looking if that important event is blanking,
32  * and if it is, we're switching backlight power as well ...
33  */
34 static int fb_notifier_callback(struct notifier_block *self,
35                                 unsigned long event, void *data)
36 {
37         struct backlight_device *bd;
38         struct fb_event *evdata = data;
39
40         /* If we aren't interested in this event, skip it immediately ... */
41         if (event != FB_EVENT_BLANK && event != FB_EVENT_CONBLANK)
42                 return 0;
43
44         bd = container_of(self, struct backlight_device, fb_notif);
45         mutex_lock(&bd->ops_lock);
46         if (bd->ops)
47                 if (!bd->ops->check_fb ||
48                     bd->ops->check_fb(bd, evdata->info)) {
49                         bd->props.fb_blank = *(int *)evdata->data;
50                         if (bd->props.fb_blank == FB_BLANK_UNBLANK)
51                                 bd->props.state &= ~BL_CORE_FBBLANK;
52                         else
53                                 bd->props.state |= BL_CORE_FBBLANK;
54                         backlight_update_status(bd);
55                 }
56         mutex_unlock(&bd->ops_lock);
57         return 0;
58 }
59
60 static int backlight_register_fb(struct backlight_device *bd)
61 {
62         memset(&bd->fb_notif, 0, sizeof(bd->fb_notif));
63         bd->fb_notif.notifier_call = fb_notifier_callback;
64
65         return fb_register_client(&bd->fb_notif);
66 }
67
68 static void backlight_unregister_fb(struct backlight_device *bd)
69 {
70         fb_unregister_client(&bd->fb_notif);
71 }
72 #else
73 static inline int backlight_register_fb(struct backlight_device *bd)
74 {
75         return 0;
76 }
77
78 static inline void backlight_unregister_fb(struct backlight_device *bd)
79 {
80 }
81 #endif /* CONFIG_FB */
82
83 static void backlight_generate_event(struct backlight_device *bd,
84                                      enum backlight_update_reason reason)
85 {
86         char *envp[2];
87
88         switch (reason) {
89         case BACKLIGHT_UPDATE_SYSFS:
90                 envp[0] = "SOURCE=sysfs";
91                 break;
92         case BACKLIGHT_UPDATE_HOTKEY:
93                 envp[0] = "SOURCE=hotkey";
94                 break;
95         default:
96                 envp[0] = "SOURCE=unknown";
97                 break;
98         }
99         envp[1] = NULL;
100         kobject_uevent_env(&bd->dev.kobj, KOBJ_CHANGE, envp);
101         sysfs_notify(&bd->dev.kobj, NULL, "actual_brightness");
102 }
103
104 static ssize_t backlight_show_power(struct device *dev,
105                 struct device_attribute *attr,char *buf)
106 {
107         struct backlight_device *bd = to_backlight_device(dev);
108
109         return sprintf(buf, "%d\n", bd->props.power);
110 }
111
112 static ssize_t backlight_store_power(struct device *dev,
113                 struct device_attribute *attr, const char *buf, size_t count)
114 {
115         int rc;
116         struct backlight_device *bd = to_backlight_device(dev);
117         unsigned long power;
118
119         rc = strict_strtoul(buf, 0, &power);
120         if (rc)
121                 return rc;
122
123         rc = -ENXIO;
124         mutex_lock(&bd->ops_lock);
125         if (bd->ops) {
126                 pr_debug("backlight: set power to %lu\n", power);
127                 if (bd->props.power != power) {
128                         bd->props.power = power;
129                         backlight_update_status(bd);
130                 }
131                 rc = count;
132         }
133         mutex_unlock(&bd->ops_lock);
134
135         return rc;
136 }
137
138 static ssize_t backlight_show_brightness(struct device *dev,
139                 struct device_attribute *attr, char *buf)
140 {
141         struct backlight_device *bd = to_backlight_device(dev);
142
143         return sprintf(buf, "%d\n", bd->props.brightness);
144 }
145
146 static ssize_t backlight_store_brightness(struct device *dev,
147                 struct device_attribute *attr, const char *buf, size_t count)
148 {
149         int rc;
150         struct backlight_device *bd = to_backlight_device(dev);
151         unsigned long brightness;
152
153         rc = strict_strtoul(buf, 0, &brightness);
154         if (rc)
155                 return rc;
156
157         rc = -ENXIO;
158
159         mutex_lock(&bd->ops_lock);
160         if (bd->ops) {
161                 if (brightness > bd->props.max_brightness)
162                         rc = -EINVAL;
163                 else {
164                         pr_debug("backlight: set brightness to %lu\n",
165                                  brightness);
166                         bd->props.brightness = brightness;
167                         backlight_update_status(bd);
168                         rc = count;
169                 }
170         }
171         mutex_unlock(&bd->ops_lock);
172
173         backlight_generate_event(bd, BACKLIGHT_UPDATE_SYSFS);
174
175         return rc;
176 }
177
178 static ssize_t backlight_show_type(struct device *dev,
179                 struct device_attribute *attr, char *buf)
180 {
181         struct backlight_device *bd = to_backlight_device(dev);
182
183         return sprintf(buf, "%s\n", backlight_types[bd->props.type]);
184 }
185
186 static ssize_t backlight_show_max_brightness(struct device *dev,
187                 struct device_attribute *attr, char *buf)
188 {
189         struct backlight_device *bd = to_backlight_device(dev);
190
191         return sprintf(buf, "%d\n", bd->props.max_brightness);
192 }
193
194 static ssize_t backlight_show_actual_brightness(struct device *dev,
195                 struct device_attribute *attr, char *buf)
196 {
197         int rc = -ENXIO;
198         struct backlight_device *bd = to_backlight_device(dev);
199
200         mutex_lock(&bd->ops_lock);
201         if (bd->ops && bd->ops->get_brightness)
202                 rc = sprintf(buf, "%d\n", bd->ops->get_brightness(bd));
203         mutex_unlock(&bd->ops_lock);
204
205         return rc;
206 }
207
208 static struct class *backlight_class;
209
210 static int backlight_suspend(struct device *dev, pm_message_t state)
211 {
212         struct backlight_device *bd = to_backlight_device(dev);
213
214         mutex_lock(&bd->ops_lock);
215         if (bd->ops && bd->ops->options & BL_CORE_SUSPENDRESUME) {
216                 bd->props.state |= BL_CORE_SUSPENDED;
217                 backlight_update_status(bd);
218         }
219         mutex_unlock(&bd->ops_lock);
220
221         return 0;
222 }
223
224 static int backlight_resume(struct device *dev)
225 {
226         struct backlight_device *bd = to_backlight_device(dev);
227
228         mutex_lock(&bd->ops_lock);
229         if (bd->ops && bd->ops->options & BL_CORE_SUSPENDRESUME) {
230                 bd->props.state &= ~BL_CORE_SUSPENDED;
231                 backlight_update_status(bd);
232         }
233         mutex_unlock(&bd->ops_lock);
234
235         return 0;
236 }
237
238 static void bl_device_release(struct device *dev)
239 {
240         struct backlight_device *bd = to_backlight_device(dev);
241         kfree(bd);
242 }
243
244 static struct device_attribute bl_device_attributes[] = {
245         __ATTR(bl_power, 0644, backlight_show_power, backlight_store_power),
246         __ATTR(brightness, 0644, backlight_show_brightness,
247                      backlight_store_brightness),
248         __ATTR(actual_brightness, 0444, backlight_show_actual_brightness,
249                      NULL),
250         __ATTR(max_brightness, 0444, backlight_show_max_brightness, NULL),
251         __ATTR(type, 0444, backlight_show_type, NULL),
252         __ATTR_NULL,
253 };
254
255 /**
256  * backlight_force_update - tell the backlight subsystem that hardware state
257  *   has changed
258  * @bd: the backlight device to update
259  *
260  * Updates the internal state of the backlight in response to a hardware event,
261  * and generate a uevent to notify userspace
262  */
263 void backlight_force_update(struct backlight_device *bd,
264                             enum backlight_update_reason reason)
265 {
266         mutex_lock(&bd->ops_lock);
267         if (bd->ops && bd->ops->get_brightness)
268                 bd->props.brightness = bd->ops->get_brightness(bd);
269         mutex_unlock(&bd->ops_lock);
270         backlight_generate_event(bd, reason);
271 }
272 EXPORT_SYMBOL(backlight_force_update);
273
274 /**
275  * backlight_device_register - create and register a new object of
276  *   backlight_device class.
277  * @name: the name of the new object(must be the same as the name of the
278  *   respective framebuffer device).
279  * @parent: a pointer to the parent device
280  * @devdata: an optional pointer to be stored for private driver use. The
281  *   methods may retrieve it by using bl_get_data(bd).
282  * @ops: the backlight operations structure.
283  *
284  * Creates and registers new backlight device. Returns either an
285  * ERR_PTR() or a pointer to the newly allocated device.
286  */
287 struct backlight_device *backlight_device_register(const char *name,
288         struct device *parent, void *devdata, const struct backlight_ops *ops,
289         const struct backlight_properties *props)
290 {
291         struct backlight_device *new_bd;
292         int rc;
293
294         pr_debug("backlight_device_register: name=%s\n", name);
295
296         new_bd = kzalloc(sizeof(struct backlight_device), GFP_KERNEL);
297         if (!new_bd)
298                 return ERR_PTR(-ENOMEM);
299
300         mutex_init(&new_bd->update_lock);
301         mutex_init(&new_bd->ops_lock);
302
303         new_bd->dev.class = backlight_class;
304         new_bd->dev.parent = parent;
305         new_bd->dev.release = bl_device_release;
306         dev_set_name(&new_bd->dev, name);
307         dev_set_drvdata(&new_bd->dev, devdata);
308
309         /* Set default properties */
310         if (props) {
311                 memcpy(&new_bd->props, props,
312                        sizeof(struct backlight_properties));
313                 if (props->type <= 0 || props->type >= BACKLIGHT_TYPE_MAX) {
314                         WARN(1, "%s: invalid backlight type", name);
315                         new_bd->props.type = BACKLIGHT_RAW;
316                 }
317         } else {
318                 new_bd->props.type = BACKLIGHT_RAW;
319         }
320
321         rc = device_register(&new_bd->dev);
322         if (rc) {
323                 kfree(new_bd);
324                 return ERR_PTR(rc);
325         }
326
327         rc = backlight_register_fb(new_bd);
328         if (rc) {
329                 device_unregister(&new_bd->dev);
330                 return ERR_PTR(rc);
331         }
332
333         new_bd->ops = ops;
334
335 #ifdef CONFIG_PMAC_BACKLIGHT
336         mutex_lock(&pmac_backlight_mutex);
337         if (!pmac_backlight)
338                 pmac_backlight = new_bd;
339         mutex_unlock(&pmac_backlight_mutex);
340 #endif
341
342         return new_bd;
343 }
344 EXPORT_SYMBOL(backlight_device_register);
345
346 /**
347  * backlight_device_unregister - unregisters a backlight device object.
348  * @bd: the backlight device object to be unregistered and freed.
349  *
350  * Unregisters a previously registered via backlight_device_register object.
351  */
352 void backlight_device_unregister(struct backlight_device *bd)
353 {
354         if (!bd)
355                 return;
356
357 #ifdef CONFIG_PMAC_BACKLIGHT
358         mutex_lock(&pmac_backlight_mutex);
359         if (pmac_backlight == bd)
360                 pmac_backlight = NULL;
361         mutex_unlock(&pmac_backlight_mutex);
362 #endif
363         mutex_lock(&bd->ops_lock);
364         bd->ops = NULL;
365         mutex_unlock(&bd->ops_lock);
366
367         backlight_unregister_fb(bd);
368         device_unregister(&bd->dev);
369 }
370 EXPORT_SYMBOL(backlight_device_unregister);
371
372 static void __exit backlight_class_exit(void)
373 {
374         class_destroy(backlight_class);
375 }
376
377 static int __init backlight_class_init(void)
378 {
379         backlight_class = class_create(THIS_MODULE, "backlight");
380         if (IS_ERR(backlight_class)) {
381                 printk(KERN_WARNING "Unable to create backlight class; errno = %ld\n",
382                                 PTR_ERR(backlight_class));
383                 return PTR_ERR(backlight_class);
384         }
385
386         backlight_class->dev_attrs = bl_device_attributes;
387         backlight_class->suspend = backlight_suspend;
388         backlight_class->resume = backlight_resume;
389         return 0;
390 }
391
392 /*
393  * if this is compiled into the kernel, we need to ensure that the
394  * class is registered before users of the class try to register lcd's
395  */
396 postcore_initcall(backlight_class_init);
397 module_exit(backlight_class_exit);
398
399 MODULE_LICENSE("GPL");
400 MODULE_AUTHOR("Jamey Hicks <jamey.hicks@hp.com>, Andrew Zabolotny <zap@homelink.ru>");
401 MODULE_DESCRIPTION("Backlight Lowlevel Control Abstraction");