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
->ops_lock
);
40 if (!bd
->ops
->check_fb
||
41 bd
->ops
->check_fb(evdata
->info
)) {
42 bd
->props
.fb_blank
= *(int *)evdata
->data
;
43 backlight_update_status(bd
);
45 mutex_unlock(&bd
->ops_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
)
74 struct backlight_device
*bd
= to_backlight_device(cdev
);
76 return sprintf(buf
, "%d\n", bd
->props
.power
);
79 static ssize_t
backlight_store_power(struct class_device
*cdev
, const char *buf
, size_t count
)
83 struct backlight_device
*bd
= to_backlight_device(cdev
);
84 int power
= simple_strtoul(buf
, &endp
, 0);
85 size_t size
= endp
- buf
;
87 if (*endp
&& isspace(*endp
))
92 mutex_lock(&bd
->ops_lock
);
94 pr_debug("backlight: set power to %d\n", power
);
95 bd
->props
.power
= power
;
96 backlight_update_status(bd
);
99 mutex_unlock(&bd
->ops_lock
);
104 static ssize_t
backlight_show_brightness(struct class_device
*cdev
, char *buf
)
106 struct backlight_device
*bd
= to_backlight_device(cdev
);
108 return sprintf(buf
, "%d\n", bd
->props
.brightness
);
111 static ssize_t
backlight_store_brightness(struct class_device
*cdev
, const char *buf
, size_t count
)
115 struct backlight_device
*bd
= to_backlight_device(cdev
);
116 int brightness
= simple_strtoul(buf
, &endp
, 0);
117 size_t size
= endp
- buf
;
119 if (*endp
&& isspace(*endp
))
124 mutex_lock(&bd
->ops_lock
);
126 if (brightness
> bd
->props
.max_brightness
)
129 pr_debug("backlight: set brightness to %d\n",
131 bd
->props
.brightness
= brightness
;
132 backlight_update_status(bd
);
136 mutex_unlock(&bd
->ops_lock
);
141 static ssize_t
backlight_show_max_brightness(struct class_device
*cdev
, char *buf
)
143 struct backlight_device
*bd
= to_backlight_device(cdev
);
145 return sprintf(buf
, "%d\n", bd
->props
.max_brightness
);
148 static ssize_t
backlight_show_actual_brightness(struct class_device
*cdev
,
152 struct backlight_device
*bd
= to_backlight_device(cdev
);
154 mutex_lock(&bd
->ops_lock
);
155 if (bd
->ops
&& bd
->ops
->get_brightness
)
156 rc
= sprintf(buf
, "%d\n", bd
->ops
->get_brightness(bd
));
157 mutex_unlock(&bd
->ops_lock
);
162 static void backlight_class_release(struct class_device
*dev
)
164 struct backlight_device
*bd
= to_backlight_device(dev
);
168 static struct class backlight_class
= {
170 .release
= backlight_class_release
,
173 #define DECLARE_ATTR(_name,_mode,_show,_store) \
175 .attr = { .name = __stringify(_name), .mode = _mode }, \
180 static const struct class_device_attribute bl_class_device_attributes
[] = {
181 DECLARE_ATTR(power
, 0644, backlight_show_power
, backlight_store_power
),
182 DECLARE_ATTR(brightness
, 0644, backlight_show_brightness
,
183 backlight_store_brightness
),
184 DECLARE_ATTR(actual_brightness
, 0444, backlight_show_actual_brightness
,
186 DECLARE_ATTR(max_brightness
, 0444, backlight_show_max_brightness
, NULL
),
190 * backlight_device_register - create and register a new object of
191 * backlight_device class.
192 * @name: the name of the new object(must be the same as the name of the
193 * respective framebuffer device).
194 * @devdata: an optional pointer to be stored in the class_device. The
195 * methods may retrieve it by using class_get_devdata(&bd->class_dev).
196 * @ops: the backlight operations structure.
198 * Creates and registers new backlight class_device. Returns either an
199 * ERR_PTR() or a pointer to the newly allocated device.
201 struct backlight_device
*backlight_device_register(const char *name
,
204 struct backlight_ops
*ops
)
207 struct backlight_device
*new_bd
;
209 pr_debug("backlight_device_alloc: name=%s\n", name
);
211 new_bd
= kzalloc(sizeof(struct backlight_device
), GFP_KERNEL
);
213 return ERR_PTR(-ENOMEM
);
215 mutex_init(&new_bd
->update_lock
);
216 mutex_init(&new_bd
->ops_lock
);
218 new_bd
->class_dev
.class = &backlight_class
;
219 new_bd
->class_dev
.dev
= dev
;
220 strlcpy(new_bd
->class_dev
.class_id
, name
, KOBJ_NAME_LEN
);
221 class_set_devdata(&new_bd
->class_dev
, devdata
);
223 rc
= class_device_register(&new_bd
->class_dev
);
229 rc
= backlight_register_fb(new_bd
);
231 class_device_unregister(&new_bd
->class_dev
);
236 for (i
= 0; i
< ARRAY_SIZE(bl_class_device_attributes
); i
++) {
237 rc
= class_device_create_file(&new_bd
->class_dev
,
238 &bl_class_device_attributes
[i
]);
241 class_device_remove_file(&new_bd
->class_dev
,
242 &bl_class_device_attributes
[i
]);
243 class_device_unregister(&new_bd
->class_dev
);
244 /* No need to kfree(new_bd) since release() method was called */
249 #ifdef CONFIG_PMAC_BACKLIGHT
250 mutex_lock(&pmac_backlight_mutex
);
252 pmac_backlight
= new_bd
;
253 mutex_unlock(&pmac_backlight_mutex
);
258 EXPORT_SYMBOL(backlight_device_register
);
261 * backlight_device_unregister - unregisters a backlight device object.
262 * @bd: the backlight device object to be unregistered and freed.
264 * Unregisters a previously registered via backlight_device_register object.
266 void backlight_device_unregister(struct backlight_device
*bd
)
273 pr_debug("backlight_device_unregister: name=%s\n", bd
->class_dev
.class_id
);
275 #ifdef CONFIG_PMAC_BACKLIGHT
276 mutex_lock(&pmac_backlight_mutex
);
277 if (pmac_backlight
== bd
)
278 pmac_backlight
= NULL
;
279 mutex_unlock(&pmac_backlight_mutex
);
282 for (i
= 0; i
< ARRAY_SIZE(bl_class_device_attributes
); i
++)
283 class_device_remove_file(&bd
->class_dev
,
284 &bl_class_device_attributes
[i
]);
286 mutex_lock(&bd
->ops_lock
);
288 mutex_unlock(&bd
->ops_lock
);
290 backlight_unregister_fb(bd
);
292 class_device_unregister(&bd
->class_dev
);
294 EXPORT_SYMBOL(backlight_device_unregister
);
296 static void __exit
backlight_class_exit(void)
298 class_unregister(&backlight_class
);
301 static int __init
backlight_class_init(void)
303 return class_register(&backlight_class
);
307 * if this is compiled into the kernel, we need to ensure that the
308 * class is registered before users of the class try to register lcd's
310 postcore_initcall(backlight_class_init
);
311 module_exit(backlight_class_exit
);
313 MODULE_LICENSE("GPL");
314 MODULE_AUTHOR("Jamey Hicks <jamey.hicks@hp.com>, Andrew Zabolotny <zap@homelink.ru>");
315 MODULE_DESCRIPTION("Backlight Lowlevel Control Abstraction");