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