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
&& bd
->props
->get_power
))
24 rc
= sprintf(buf
, "%d\n", bd
->props
->get_power(bd
));
32 static ssize_t
backlight_store_power(struct class_device
*cdev
, const char *buf
, size_t count
)
36 struct backlight_device
*bd
= to_backlight_device(cdev
);
38 power
= simple_strtoul(buf
, &endp
, 0);
39 if (*endp
&& !isspace(*endp
))
43 if (likely(bd
->props
&& bd
->props
->set_power
)) {
44 pr_debug("backlight: set power to %d\n", power
);
45 bd
->props
->set_power(bd
, power
);
54 static ssize_t
backlight_show_brightness(struct class_device
*cdev
, char *buf
)
57 struct backlight_device
*bd
= to_backlight_device(cdev
);
60 if (likely(bd
->props
&& bd
->props
->get_brightness
))
61 rc
= sprintf(buf
, "%d\n", bd
->props
->get_brightness(bd
));
69 static ssize_t
backlight_store_brightness(struct class_device
*cdev
, const char *buf
, size_t count
)
73 struct backlight_device
*bd
= to_backlight_device(cdev
);
75 brightness
= simple_strtoul(buf
, &endp
, 0);
76 if (*endp
&& !isspace(*endp
))
80 if (likely(bd
->props
&& bd
->props
->set_brightness
)) {
81 pr_debug("backlight: set brightness to %d\n", brightness
);
82 bd
->props
->set_brightness(bd
, brightness
);
91 static ssize_t
backlight_show_max_brightness(struct class_device
*cdev
, char *buf
)
94 struct backlight_device
*bd
= to_backlight_device(cdev
);
97 if (likely(bd
->props
))
98 rc
= sprintf(buf
, "%d\n", bd
->props
->max_brightness
);
106 static void backlight_class_release(struct class_device
*dev
)
108 struct backlight_device
*bd
= to_backlight_device(dev
);
112 static struct class backlight_class
= {
114 .release
= backlight_class_release
,
117 #define DECLARE_ATTR(_name,_mode,_show,_store) \
119 .attr = { .name = __stringify(_name), .mode = _mode, .owner = THIS_MODULE }, \
124 static struct class_device_attribute bl_class_device_attributes
[] = {
125 DECLARE_ATTR(power
, 0644, backlight_show_power
, backlight_store_power
),
126 DECLARE_ATTR(brightness
, 0644, backlight_show_brightness
, backlight_store_brightness
),
127 DECLARE_ATTR(max_brightness
, 0444, backlight_show_max_brightness
, NULL
),
130 /* This callback gets called when something important happens inside a
131 * framebuffer driver. We're looking if that important event is blanking,
132 * and if it is, we're switching backlight power as well ...
134 static int fb_notifier_callback(struct notifier_block
*self
,
135 unsigned long event
, void *data
)
137 struct backlight_device
*bd
;
138 struct fb_event
*evdata
=(struct fb_event
*)data
;
140 /* If we aren't interested in this event, skip it immediately ... */
141 if (event
!= FB_EVENT_BLANK
)
144 bd
= container_of(self
, struct backlight_device
, fb_notif
);
147 if (!bd
->props
->check_fb
|| bd
->props
->check_fb(evdata
->info
))
148 bd
->props
->set_power(bd
, *(int *)evdata
->data
);
154 * backlight_device_register - create and register a new object of
155 * backlight_device class.
156 * @name: the name of the new object(must be the same as the name of the
157 * respective framebuffer device).
158 * @devdata: an optional pointer to be stored in the class_device. The
159 * methods may retrieve it by using class_get_devdata(&bd->class_dev).
160 * @bp: the backlight properties structure.
162 * Creates and registers new backlight class_device. Returns either an
163 * ERR_PTR() or a pointer to the newly allocated device.
165 struct backlight_device
*backlight_device_register(const char *name
, void *devdata
,
166 struct backlight_properties
*bp
)
169 struct backlight_device
*new_bd
;
171 pr_debug("backlight_device_alloc: name=%s\n", name
);
173 new_bd
= kmalloc(sizeof(struct backlight_device
), GFP_KERNEL
);
174 if (unlikely(!new_bd
))
175 return ERR_PTR(ENOMEM
);
177 init_MUTEX(&new_bd
->sem
);
179 memset(&new_bd
->class_dev
, 0, sizeof(new_bd
->class_dev
));
180 new_bd
->class_dev
.class = &backlight_class
;
181 strlcpy(new_bd
->class_dev
.class_id
, name
, KOBJ_NAME_LEN
);
182 class_set_devdata(&new_bd
->class_dev
, devdata
);
184 rc
= class_device_register(&new_bd
->class_dev
);
186 error
: kfree(new_bd
);
190 memset(&new_bd
->fb_notif
, 0, sizeof(new_bd
->fb_notif
));
191 new_bd
->fb_notif
.notifier_call
= fb_notifier_callback
;
193 rc
= fb_register_client(&new_bd
->fb_notif
);
197 for (i
= 0; i
< ARRAY_SIZE(bl_class_device_attributes
); i
++) {
198 rc
= class_device_create_file(&new_bd
->class_dev
,
199 &bl_class_device_attributes
[i
]);
202 class_device_remove_file(&new_bd
->class_dev
,
203 &bl_class_device_attributes
[i
]);
204 class_device_unregister(&new_bd
->class_dev
);
205 /* No need to kfree(new_bd) since release() method was called */
212 EXPORT_SYMBOL(backlight_device_register
);
215 * backlight_device_unregister - unregisters a backlight device object.
216 * @bd: the backlight device object to be unregistered and freed.
218 * Unregisters a previously registered via backlight_device_register object.
220 void backlight_device_unregister(struct backlight_device
*bd
)
227 pr_debug("backlight_device_unregister: name=%s\n", bd
->class_dev
.class_id
);
229 for (i
= 0; i
< ARRAY_SIZE(bl_class_device_attributes
); i
++)
230 class_device_remove_file(&bd
->class_dev
,
231 &bl_class_device_attributes
[i
]);
237 fb_unregister_client(&bd
->fb_notif
);
239 class_device_unregister(&bd
->class_dev
);
241 EXPORT_SYMBOL(backlight_device_unregister
);
243 static void __exit
backlight_class_exit(void)
245 class_unregister(&backlight_class
);
248 static int __init
backlight_class_init(void)
250 return class_register(&backlight_class
);
254 * if this is compiled into the kernel, we need to ensure that the
255 * class is registered before users of the class try to register lcd's
257 postcore_initcall(backlight_class_init
);
258 module_exit(backlight_class_exit
);
260 MODULE_LICENSE("GPL");
261 MODULE_AUTHOR("Jamey Hicks <jamey.hicks@hp.com>, Andrew Zabolotny <zap@homelink.ru>");
262 MODULE_DESCRIPTION("Backlight Lowlevel Control Abstraction");