2 * Backlight Lowlevel Control Abstraction
4 * Copyright (C) 2003,2004 Hewlett-Packard Company
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>
17 #ifdef CONFIG_PMAC_BACKLIGHT
18 #include <asm/backlight.h>
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 ...
27 static int fb_notifier_callback(struct notifier_block *self,
28 unsigned long event, void *data)
30 struct backlight_device *bd;
31 struct fb_event *evdata = data;
33 /* If we aren't interested in this event, skip it immediately ... */
34 if (event != FB_EVENT_BLANK && event != FB_EVENT_CONBLANK)
37 bd = container_of(self, struct backlight_device, fb_notif);
38 mutex_lock(&bd->props_lock);
40 if (!bd->props->check_fb ||
41 bd->props->check_fb(evdata->info)) {
42 bd->props->fb_blank = *(int *)evdata->data;
43 backlight_update_status(bd);
45 mutex_unlock(&bd->props_lock);
49 static int backlight_register_fb(struct backlight_device *bd)
51 memset(&bd->fb_notif, 0, sizeof(bd->fb_notif));
52 bd->fb_notif.notifier_call = fb_notifier_callback;
54 return fb_register_client(&bd->fb_notif);
57 static void backlight_unregister_fb(struct backlight_device *bd)
59 fb_unregister_client(&bd->fb_notif);
62 static inline int backlight_register_fb(struct backlight_device *bd)
67 static inline void backlight_unregister_fb(struct backlight_device *bd)
70 #endif /* CONFIG_FB */
72 static ssize_t backlight_show_power(struct class_device *cdev, char *buf)
75 struct backlight_device *bd = to_backlight_device(cdev);
77 mutex_lock(&bd->props_lock);
79 rc = sprintf(buf, "%d\n", bd->props->power);
80 mutex_unlock(&bd->props_lock);
85 static ssize_t backlight_store_power(struct class_device *cdev, const char *buf, size_t count)
89 struct backlight_device *bd = to_backlight_device(cdev);
90 int power = simple_strtoul(buf, &endp, 0);
91 size_t size = endp - buf;
93 if (*endp && isspace(*endp))
98 mutex_lock(&bd->props_lock);
100 pr_debug("backlight: set power to %d\n", power);
101 bd->props->power = power;
102 backlight_update_status(bd);
105 mutex_unlock(&bd->props_lock);
110 static ssize_t backlight_show_brightness(struct class_device *cdev, char *buf)
113 struct backlight_device *bd = to_backlight_device(cdev);
115 mutex_lock(&bd->props_lock);
117 rc = sprintf(buf, "%d\n", bd->props->brightness);
118 mutex_unlock(&bd->props_lock);
123 static ssize_t backlight_store_brightness(struct class_device *cdev, const char *buf, size_t count)
127 struct backlight_device *bd = to_backlight_device(cdev);
128 int brightness = simple_strtoul(buf, &endp, 0);
129 size_t size = endp - buf;
131 if (*endp && isspace(*endp))
136 mutex_lock(&bd->props_lock);
138 if (brightness > bd->props->max_brightness)
141 pr_debug("backlight: set brightness to %d\n",
143 bd->props->brightness = brightness;
144 backlight_update_status(bd);
148 mutex_unlock(&bd->props_lock);
153 static ssize_t backlight_show_max_brightness(struct class_device *cdev, char *buf)
156 struct backlight_device *bd = to_backlight_device(cdev);
158 mutex_lock(&bd->props_lock);
160 rc = sprintf(buf, "%d\n", bd->props->max_brightness);
161 mutex_unlock(&bd->props_lock);
166 static ssize_t backlight_show_actual_brightness(struct class_device *cdev,
170 struct backlight_device *bd = to_backlight_device(cdev);
172 mutex_lock(&bd->props_lock);
173 if (bd->props && bd->props->get_brightness)
174 rc = sprintf(buf, "%d\n", bd->props->get_brightness(bd));
175 mutex_unlock(&bd->props_lock);
180 static void backlight_class_release(struct class_device *dev)
182 struct backlight_device *bd = to_backlight_device(dev);
186 static struct class backlight_class = {
188 .release = backlight_class_release,
191 #define DECLARE_ATTR(_name,_mode,_show,_store) \
193 .attr = { .name = __stringify(_name), .mode = _mode, .owner = THIS_MODULE }, \
198 static const struct class_device_attribute bl_class_device_attributes[] = {
199 DECLARE_ATTR(power, 0644, backlight_show_power, backlight_store_power),
200 DECLARE_ATTR(brightness, 0644, backlight_show_brightness,
201 backlight_store_brightness),
202 DECLARE_ATTR(actual_brightness, 0444, backlight_show_actual_brightness,
204 DECLARE_ATTR(max_brightness, 0444, backlight_show_max_brightness, NULL),
208 * backlight_device_register - create and register a new object of
209 * backlight_device class.
210 * @name: the name of the new object(must be the same as the name of the
211 * respective framebuffer device).
212 * @devdata: an optional pointer to be stored in the class_device. The
213 * methods may retrieve it by using class_get_devdata(&bd->class_dev).
214 * @bp: the backlight properties structure.
216 * Creates and registers new backlight class_device. Returns either an
217 * ERR_PTR() or a pointer to the newly allocated device.
219 struct backlight_device *backlight_device_register(const char *name,
222 struct backlight_properties *bp)
225 struct backlight_device *new_bd;
227 pr_debug("backlight_device_alloc: name=%s\n", name);
229 new_bd = kmalloc(sizeof(struct backlight_device), GFP_KERNEL);
231 return ERR_PTR(-ENOMEM);
233 mutex_init(&new_bd->update_lock);
234 mutex_init(&new_bd->props_lock);
236 memset(&new_bd->class_dev, 0, sizeof(new_bd->class_dev));
237 new_bd->class_dev.class = &backlight_class;
238 new_bd->class_dev.dev = dev;
239 strlcpy(new_bd->class_dev.class_id, name, KOBJ_NAME_LEN);
240 class_set_devdata(&new_bd->class_dev, devdata);
242 rc = class_device_register(&new_bd->class_dev);
248 rc = backlight_register_fb(new_bd);
250 class_device_unregister(&new_bd->class_dev);
255 for (i = 0; i < ARRAY_SIZE(bl_class_device_attributes); i++) {
256 rc = class_device_create_file(&new_bd->class_dev,
257 &bl_class_device_attributes[i]);
260 class_device_remove_file(&new_bd->class_dev,
261 &bl_class_device_attributes[i]);
262 class_device_unregister(&new_bd->class_dev);
263 /* No need to kfree(new_bd) since release() method was called */
268 #ifdef CONFIG_PMAC_BACKLIGHT
269 mutex_lock(&pmac_backlight_mutex);
271 pmac_backlight = new_bd;
272 mutex_unlock(&pmac_backlight_mutex);
277 EXPORT_SYMBOL(backlight_device_register);
280 * backlight_device_unregister - unregisters a backlight device object.
281 * @bd: the backlight device object to be unregistered and freed.
283 * Unregisters a previously registered via backlight_device_register object.
285 void backlight_device_unregister(struct backlight_device *bd)
292 pr_debug("backlight_device_unregister: name=%s\n", bd->class_dev.class_id);
294 #ifdef CONFIG_PMAC_BACKLIGHT
295 mutex_lock(&pmac_backlight_mutex);
296 if (pmac_backlight == bd)
297 pmac_backlight = NULL;
298 mutex_unlock(&pmac_backlight_mutex);
301 for (i = 0; i < ARRAY_SIZE(bl_class_device_attributes); i++)
302 class_device_remove_file(&bd->class_dev,
303 &bl_class_device_attributes[i]);
305 mutex_lock(&bd->props_lock);
307 mutex_unlock(&bd->props_lock);
309 backlight_unregister_fb(bd);
311 class_device_unregister(&bd->class_dev);
313 EXPORT_SYMBOL(backlight_device_unregister);
315 static void __exit backlight_class_exit(void)
317 class_unregister(&backlight_class);
320 static int __init backlight_class_init(void)
322 return class_register(&backlight_class);
326 * if this is compiled into the kernel, we need to ensure that the
327 * class is registered before users of the class try to register lcd's
329 postcore_initcall(backlight_class_init);
330 module_exit(backlight_class_exit);
332 MODULE_LICENSE("GPL");
333 MODULE_AUTHOR("Jamey Hicks <jamey.hicks@hp.com>, Andrew Zabolotny <zap@homelink.ru>");
334 MODULE_DESCRIPTION("Backlight Lowlevel Control Abstraction");