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 if (!lock_fb_info(evdata
->info
))
40 mutex_lock(&bd
->ops_lock
);
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
;
48 bd
->props
.state
|= BL_CORE_FBBLANK
;
49 backlight_update_status(bd
);
51 mutex_unlock(&bd
->ops_lock
);
52 unlock_fb_info(evdata
->info
);
56 static int backlight_register_fb(struct backlight_device
*bd
)
58 memset(&bd
->fb_notif
, 0, sizeof(bd
->fb_notif
));
59 bd
->fb_notif
.notifier_call
= fb_notifier_callback
;
61 return fb_register_client(&bd
->fb_notif
);
64 static void backlight_unregister_fb(struct backlight_device
*bd
)
66 fb_unregister_client(&bd
->fb_notif
);
69 static inline int backlight_register_fb(struct backlight_device
*bd
)
74 static inline void backlight_unregister_fb(struct backlight_device
*bd
)
77 #endif /* CONFIG_FB */
79 static ssize_t
backlight_show_power(struct device
*dev
,
80 struct device_attribute
*attr
,char *buf
)
82 struct backlight_device
*bd
= to_backlight_device(dev
);
84 return sprintf(buf
, "%d\n", bd
->props
.power
);
87 static ssize_t
backlight_store_power(struct device
*dev
,
88 struct device_attribute
*attr
, const char *buf
, size_t count
)
91 struct backlight_device
*bd
= to_backlight_device(dev
);
94 rc
= strict_strtoul(buf
, 0, &power
);
99 mutex_lock(&bd
->ops_lock
);
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
);
108 mutex_unlock(&bd
->ops_lock
);
113 static ssize_t
backlight_show_brightness(struct device
*dev
,
114 struct device_attribute
*attr
, char *buf
)
116 struct backlight_device
*bd
= to_backlight_device(dev
);
118 return sprintf(buf
, "%d\n", bd
->props
.brightness
);
121 static ssize_t
backlight_store_brightness(struct device
*dev
,
122 struct device_attribute
*attr
, const char *buf
, size_t count
)
125 struct backlight_device
*bd
= to_backlight_device(dev
);
126 unsigned long brightness
;
128 rc
= strict_strtoul(buf
, 0, &brightness
);
134 mutex_lock(&bd
->ops_lock
);
136 if (brightness
> bd
->props
.max_brightness
)
139 pr_debug("backlight: set brightness to %lu\n",
141 bd
->props
.brightness
= brightness
;
142 backlight_update_status(bd
);
146 mutex_unlock(&bd
->ops_lock
);
151 static ssize_t
backlight_show_max_brightness(struct device
*dev
,
152 struct device_attribute
*attr
, char *buf
)
154 struct backlight_device
*bd
= to_backlight_device(dev
);
156 return sprintf(buf
, "%d\n", bd
->props
.max_brightness
);
159 static ssize_t
backlight_show_actual_brightness(struct device
*dev
,
160 struct device_attribute
*attr
, char *buf
)
163 struct backlight_device
*bd
= to_backlight_device(dev
);
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
);
173 static struct class *backlight_class
;
175 static int backlight_suspend(struct device
*dev
, pm_message_t state
)
177 struct backlight_device
*bd
= to_backlight_device(dev
);
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
);
189 static int backlight_resume(struct device
*dev
)
191 struct backlight_device
*bd
= to_backlight_device(dev
);
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
);
203 static void bl_device_release(struct device
*dev
)
205 struct backlight_device
*bd
= to_backlight_device(dev
);
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
,
215 __ATTR(max_brightness
, 0444, backlight_show_max_brightness
, NULL
),
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.
229 * Creates and registers new backlight device. Returns either an
230 * ERR_PTR() or a pointer to the newly allocated device.
232 struct backlight_device
*backlight_device_register(const char *name
,
233 struct device
*parent
, void *devdata
, struct backlight_ops
*ops
)
235 struct backlight_device
*new_bd
;
238 pr_debug("backlight_device_register: name=%s\n", name
);
240 new_bd
= kzalloc(sizeof(struct backlight_device
), GFP_KERNEL
);
242 return ERR_PTR(-ENOMEM
);
244 mutex_init(&new_bd
->update_lock
);
245 mutex_init(&new_bd
->ops_lock
);
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
);
253 rc
= device_register(&new_bd
->dev
);
259 rc
= backlight_register_fb(new_bd
);
261 device_unregister(&new_bd
->dev
);
267 #ifdef CONFIG_PMAC_BACKLIGHT
268 mutex_lock(&pmac_backlight_mutex
);
270 pmac_backlight
= new_bd
;
271 mutex_unlock(&pmac_backlight_mutex
);
276 EXPORT_SYMBOL(backlight_device_register
);
279 * backlight_device_unregister - unregisters a backlight device object.
280 * @bd: the backlight device object to be unregistered and freed.
282 * Unregisters a previously registered via backlight_device_register object.
284 void backlight_device_unregister(struct backlight_device
*bd
)
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
);
295 mutex_lock(&bd
->ops_lock
);
297 mutex_unlock(&bd
->ops_lock
);
299 backlight_unregister_fb(bd
);
300 device_unregister(&bd
->dev
);
302 EXPORT_SYMBOL(backlight_device_unregister
);
304 static void __exit
backlight_class_exit(void)
306 class_destroy(backlight_class
);
309 static int __init
backlight_class_init(void)
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
);
318 backlight_class
->dev_attrs
= bl_device_attributes
;
319 backlight_class
->suspend
= backlight_suspend
;
320 backlight_class
->resume
= backlight_resume
;
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
328 postcore_initcall(backlight_class_init
);
329 module_exit(backlight_class_exit
);
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");