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 static ssize_t
backlight_show_power(struct class_device
*cdev
, char *buf
)
20 struct backlight_device
*bd
= to_backlight_device(cdev
);
23 if (likely(bd
->props
))
24 rc
= sprintf(buf
, "%d\n", bd
->props
->power
);
30 static ssize_t
backlight_store_power(struct class_device
*cdev
, const char *buf
, size_t count
)
32 int rc
= -ENXIO
, power
;
34 struct backlight_device
*bd
= to_backlight_device(cdev
);
36 power
= simple_strtoul(buf
, &endp
, 0);
37 if (*endp
&& !isspace(*endp
))
41 if (likely(bd
->props
)) {
42 pr_debug("backlight: set power to %d\n", power
);
43 bd
->props
->power
= power
;
44 if (likely(bd
->props
->update_status
))
45 bd
->props
->update_status(bd
);
53 static ssize_t
backlight_show_brightness(struct class_device
*cdev
, char *buf
)
56 struct backlight_device
*bd
= to_backlight_device(cdev
);
59 if (likely(bd
->props
))
60 rc
= sprintf(buf
, "%d\n", bd
->props
->brightness
);
66 static ssize_t
backlight_store_brightness(struct class_device
*cdev
, const char *buf
, size_t count
)
68 int rc
= -ENXIO
, brightness
;
70 struct backlight_device
*bd
= to_backlight_device(cdev
);
72 brightness
= simple_strtoul(buf
, &endp
, 0);
73 if (*endp
&& !isspace(*endp
))
77 if (likely(bd
->props
)) {
78 if (brightness
> bd
->props
->max_brightness
)
81 pr_debug("backlight: set brightness to %d\n",
83 bd
->props
->brightness
= brightness
;
84 if (likely(bd
->props
->update_status
))
85 bd
->props
->update_status(bd
);
94 static ssize_t
backlight_show_max_brightness(struct class_device
*cdev
, char *buf
)
97 struct backlight_device
*bd
= to_backlight_device(cdev
);
100 if (likely(bd
->props
))
101 rc
= sprintf(buf
, "%d\n", bd
->props
->max_brightness
);
107 static ssize_t
backlight_show_actual_brightness(struct class_device
*cdev
,
111 struct backlight_device
*bd
= to_backlight_device(cdev
);
114 if (likely(bd
->props
&& bd
->props
->get_brightness
))
115 rc
= sprintf(buf
, "%d\n", bd
->props
->get_brightness(bd
));
121 static void backlight_class_release(struct class_device
*dev
)
123 struct backlight_device
*bd
= to_backlight_device(dev
);
127 static struct class backlight_class
= {
129 .release
= backlight_class_release
,
132 #define DECLARE_ATTR(_name,_mode,_show,_store) \
134 .attr = { .name = __stringify(_name), .mode = _mode, .owner = THIS_MODULE }, \
139 static struct class_device_attribute bl_class_device_attributes
[] = {
140 DECLARE_ATTR(power
, 0644, backlight_show_power
, backlight_store_power
),
141 DECLARE_ATTR(brightness
, 0644, backlight_show_brightness
,
142 backlight_store_brightness
),
143 DECLARE_ATTR(actual_brightness
, 0444, backlight_show_actual_brightness
,
145 DECLARE_ATTR(max_brightness
, 0444, backlight_show_max_brightness
, NULL
),
148 /* This callback gets called when something important happens inside a
149 * framebuffer driver. We're looking if that important event is blanking,
150 * and if it is, we're switching backlight power as well ...
152 static int fb_notifier_callback(struct notifier_block
*self
,
153 unsigned long event
, void *data
)
155 struct backlight_device
*bd
;
156 struct fb_event
*evdata
=(struct fb_event
*)data
;
158 /* If we aren't interested in this event, skip it immediately ... */
159 if (event
!= FB_EVENT_BLANK
)
162 bd
= container_of(self
, struct backlight_device
, fb_notif
);
165 if (!bd
->props
->check_fb
||
166 bd
->props
->check_fb(evdata
->info
)) {
167 bd
->props
->fb_blank
= *(int *)evdata
->data
;
168 if (likely(bd
->props
&& bd
->props
->update_status
))
169 bd
->props
->update_status(bd
);
176 * backlight_device_register - create and register a new object of
177 * backlight_device class.
178 * @name: the name of the new object(must be the same as the name of the
179 * respective framebuffer device).
180 * @devdata: an optional pointer to be stored in the class_device. The
181 * methods may retrieve it by using class_get_devdata(&bd->class_dev).
182 * @bp: the backlight properties structure.
184 * Creates and registers new backlight class_device. Returns either an
185 * ERR_PTR() or a pointer to the newly allocated device.
187 struct backlight_device
*backlight_device_register(const char *name
, void *devdata
,
188 struct backlight_properties
*bp
)
191 struct backlight_device
*new_bd
;
193 pr_debug("backlight_device_alloc: name=%s\n", name
);
195 new_bd
= kmalloc(sizeof(struct backlight_device
), GFP_KERNEL
);
196 if (unlikely(!new_bd
))
197 return ERR_PTR(-ENOMEM
);
199 init_MUTEX(&new_bd
->sem
);
201 memset(&new_bd
->class_dev
, 0, sizeof(new_bd
->class_dev
));
202 new_bd
->class_dev
.class = &backlight_class
;
203 strlcpy(new_bd
->class_dev
.class_id
, name
, KOBJ_NAME_LEN
);
204 class_set_devdata(&new_bd
->class_dev
, devdata
);
206 rc
= class_device_register(&new_bd
->class_dev
);
208 error
: kfree(new_bd
);
212 memset(&new_bd
->fb_notif
, 0, sizeof(new_bd
->fb_notif
));
213 new_bd
->fb_notif
.notifier_call
= fb_notifier_callback
;
215 rc
= fb_register_client(&new_bd
->fb_notif
);
219 for (i
= 0; i
< ARRAY_SIZE(bl_class_device_attributes
); i
++) {
220 rc
= class_device_create_file(&new_bd
->class_dev
,
221 &bl_class_device_attributes
[i
]);
224 class_device_remove_file(&new_bd
->class_dev
,
225 &bl_class_device_attributes
[i
]);
226 class_device_unregister(&new_bd
->class_dev
);
227 /* No need to kfree(new_bd) since release() method was called */
234 EXPORT_SYMBOL(backlight_device_register
);
237 * backlight_device_unregister - unregisters a backlight device object.
238 * @bd: the backlight device object to be unregistered and freed.
240 * Unregisters a previously registered via backlight_device_register object.
242 void backlight_device_unregister(struct backlight_device
*bd
)
249 pr_debug("backlight_device_unregister: name=%s\n", bd
->class_dev
.class_id
);
251 for (i
= 0; i
< ARRAY_SIZE(bl_class_device_attributes
); i
++)
252 class_device_remove_file(&bd
->class_dev
,
253 &bl_class_device_attributes
[i
]);
256 if (likely(bd
->props
&& bd
->props
->update_status
)) {
257 bd
->props
->brightness
= 0;
258 bd
->props
->power
= 0;
259 bd
->props
->update_status(bd
);
265 fb_unregister_client(&bd
->fb_notif
);
267 class_device_unregister(&bd
->class_dev
);
269 EXPORT_SYMBOL(backlight_device_unregister
);
271 static void __exit
backlight_class_exit(void)
273 class_unregister(&backlight_class
);
276 static int __init
backlight_class_init(void)
278 return class_register(&backlight_class
);
282 * if this is compiled into the kernel, we need to ensure that the
283 * class is registered before users of the class try to register lcd's
285 postcore_initcall(backlight_class_init
);
286 module_exit(backlight_class_exit
);
288 MODULE_LICENSE("GPL");
289 MODULE_AUTHOR("Jamey Hicks <jamey.hicks@hp.com>, Andrew Zabolotny <zap@homelink.ru>");
290 MODULE_DESCRIPTION("Backlight Lowlevel Control Abstraction");