2 * Backlight Lowlevel Control Abstraction
4 * Copyright (C) 2003,2004 Hewlett-Packard Company
8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10 #include <linux/module.h>
11 #include <linux/init.h>
12 #include <linux/device.h>
13 #include <linux/backlight.h>
14 #include <linux/notifier.h>
15 #include <linux/ctype.h>
16 #include <linux/err.h>
18 #include <linux/slab.h>
20 #ifdef CONFIG_PMAC_BACKLIGHT
21 #include <asm/backlight.h>
24 static struct list_head backlight_dev_list
;
25 static struct mutex backlight_dev_list_mutex
;
27 static const char *const backlight_types
[] = {
28 [BACKLIGHT_RAW
] = "raw",
29 [BACKLIGHT_PLATFORM
] = "platform",
30 [BACKLIGHT_FIRMWARE
] = "firmware",
33 #if defined(CONFIG_FB) || (defined(CONFIG_FB_MODULE) && \
34 defined(CONFIG_BACKLIGHT_CLASS_DEVICE_MODULE))
35 /* This callback gets called when something important happens inside a
36 * framebuffer driver. We're looking if that important event is blanking,
37 * and if it is and necessary, we're switching backlight power as well ...
39 static int fb_notifier_callback(struct notifier_block
*self
,
40 unsigned long event
, void *data
)
42 struct backlight_device
*bd
;
43 struct fb_event
*evdata
= data
;
44 int node
= evdata
->info
->node
;
47 /* If we aren't interested in this event, skip it immediately ... */
48 if (event
!= FB_EVENT_BLANK
&& event
!= FB_EVENT_CONBLANK
)
51 bd
= container_of(self
, struct backlight_device
, fb_notif
);
52 mutex_lock(&bd
->ops_lock
);
54 if (!bd
->ops
->check_fb
||
55 bd
->ops
->check_fb(bd
, evdata
->info
)) {
56 fb_blank
= *(int *)evdata
->data
;
57 if (fb_blank
== FB_BLANK_UNBLANK
&&
58 !bd
->fb_bl_on
[node
]) {
59 bd
->fb_bl_on
[node
] = true;
60 if (!bd
->use_count
++) {
61 bd
->props
.state
&= ~BL_CORE_FBBLANK
;
62 bd
->props
.fb_blank
= FB_BLANK_UNBLANK
;
63 backlight_update_status(bd
);
65 } else if (fb_blank
!= FB_BLANK_UNBLANK
&&
67 bd
->fb_bl_on
[node
] = false;
68 if (!(--bd
->use_count
)) {
69 bd
->props
.state
|= BL_CORE_FBBLANK
;
70 bd
->props
.fb_blank
= fb_blank
;
71 backlight_update_status(bd
);
75 mutex_unlock(&bd
->ops_lock
);
79 static int backlight_register_fb(struct backlight_device
*bd
)
81 memset(&bd
->fb_notif
, 0, sizeof(bd
->fb_notif
));
82 bd
->fb_notif
.notifier_call
= fb_notifier_callback
;
84 return fb_register_client(&bd
->fb_notif
);
87 static void backlight_unregister_fb(struct backlight_device
*bd
)
89 fb_unregister_client(&bd
->fb_notif
);
92 static inline int backlight_register_fb(struct backlight_device
*bd
)
97 static inline void backlight_unregister_fb(struct backlight_device
*bd
)
100 #endif /* CONFIG_FB */
102 static void backlight_generate_event(struct backlight_device
*bd
,
103 enum backlight_update_reason reason
)
108 case BACKLIGHT_UPDATE_SYSFS
:
109 envp
[0] = "SOURCE=sysfs";
111 case BACKLIGHT_UPDATE_HOTKEY
:
112 envp
[0] = "SOURCE=hotkey";
115 envp
[0] = "SOURCE=unknown";
119 kobject_uevent_env(&bd
->dev
.kobj
, KOBJ_CHANGE
, envp
);
120 sysfs_notify(&bd
->dev
.kobj
, NULL
, "actual_brightness");
123 static ssize_t
bl_power_show(struct device
*dev
, struct device_attribute
*attr
,
126 struct backlight_device
*bd
= to_backlight_device(dev
);
128 return sprintf(buf
, "%d\n", bd
->props
.power
);
131 static ssize_t
bl_power_store(struct device
*dev
, struct device_attribute
*attr
,
132 const char *buf
, size_t count
)
135 struct backlight_device
*bd
= to_backlight_device(dev
);
138 rc
= kstrtoul(buf
, 0, &power
);
143 mutex_lock(&bd
->ops_lock
);
145 pr_debug("set power to %lu\n", power
);
146 if (bd
->props
.power
!= power
) {
147 bd
->props
.power
= power
;
148 backlight_update_status(bd
);
152 mutex_unlock(&bd
->ops_lock
);
156 static DEVICE_ATTR_RW(bl_power
);
158 static ssize_t
brightness_show(struct device
*dev
,
159 struct device_attribute
*attr
, char *buf
)
161 struct backlight_device
*bd
= to_backlight_device(dev
);
163 return sprintf(buf
, "%d\n", bd
->props
.brightness
);
166 static ssize_t
brightness_store(struct device
*dev
,
167 struct device_attribute
*attr
, const char *buf
, size_t count
)
170 struct backlight_device
*bd
= to_backlight_device(dev
);
171 unsigned long brightness
;
173 rc
= kstrtoul(buf
, 0, &brightness
);
179 mutex_lock(&bd
->ops_lock
);
181 if (brightness
> bd
->props
.max_brightness
)
184 pr_debug("set brightness to %lu\n", brightness
);
185 bd
->props
.brightness
= brightness
;
186 backlight_update_status(bd
);
190 mutex_unlock(&bd
->ops_lock
);
192 backlight_generate_event(bd
, BACKLIGHT_UPDATE_SYSFS
);
196 static DEVICE_ATTR_RW(brightness
);
198 static ssize_t
type_show(struct device
*dev
, struct device_attribute
*attr
,
201 struct backlight_device
*bd
= to_backlight_device(dev
);
203 return sprintf(buf
, "%s\n", backlight_types
[bd
->props
.type
]);
205 static DEVICE_ATTR_RO(type
);
207 static ssize_t
max_brightness_show(struct device
*dev
,
208 struct device_attribute
*attr
, char *buf
)
210 struct backlight_device
*bd
= to_backlight_device(dev
);
212 return sprintf(buf
, "%d\n", bd
->props
.max_brightness
);
214 static DEVICE_ATTR_RO(max_brightness
);
216 static ssize_t
actual_brightness_show(struct device
*dev
,
217 struct device_attribute
*attr
, char *buf
)
220 struct backlight_device
*bd
= to_backlight_device(dev
);
222 mutex_lock(&bd
->ops_lock
);
223 if (bd
->ops
&& bd
->ops
->get_brightness
)
224 rc
= sprintf(buf
, "%d\n", bd
->ops
->get_brightness(bd
));
225 mutex_unlock(&bd
->ops_lock
);
229 static DEVICE_ATTR_RO(actual_brightness
);
231 static struct class *backlight_class
;
233 #ifdef CONFIG_PM_SLEEP
234 static int backlight_suspend(struct device
*dev
)
236 struct backlight_device
*bd
= to_backlight_device(dev
);
238 mutex_lock(&bd
->ops_lock
);
239 if (bd
->ops
&& bd
->ops
->options
& BL_CORE_SUSPENDRESUME
) {
240 bd
->props
.state
|= BL_CORE_SUSPENDED
;
241 backlight_update_status(bd
);
243 mutex_unlock(&bd
->ops_lock
);
248 static int backlight_resume(struct device
*dev
)
250 struct backlight_device
*bd
= to_backlight_device(dev
);
252 mutex_lock(&bd
->ops_lock
);
253 if (bd
->ops
&& bd
->ops
->options
& BL_CORE_SUSPENDRESUME
) {
254 bd
->props
.state
&= ~BL_CORE_SUSPENDED
;
255 backlight_update_status(bd
);
257 mutex_unlock(&bd
->ops_lock
);
263 static SIMPLE_DEV_PM_OPS(backlight_class_dev_pm_ops
, backlight_suspend
,
266 static void bl_device_release(struct device
*dev
)
268 struct backlight_device
*bd
= to_backlight_device(dev
);
272 static struct attribute
*bl_device_attrs
[] = {
273 &dev_attr_bl_power
.attr
,
274 &dev_attr_brightness
.attr
,
275 &dev_attr_actual_brightness
.attr
,
276 &dev_attr_max_brightness
.attr
,
280 ATTRIBUTE_GROUPS(bl_device
);
283 * backlight_force_update - tell the backlight subsystem that hardware state
285 * @bd: the backlight device to update
287 * Updates the internal state of the backlight in response to a hardware event,
288 * and generate a uevent to notify userspace
290 void backlight_force_update(struct backlight_device
*bd
,
291 enum backlight_update_reason reason
)
293 mutex_lock(&bd
->ops_lock
);
294 if (bd
->ops
&& bd
->ops
->get_brightness
)
295 bd
->props
.brightness
= bd
->ops
->get_brightness(bd
);
296 mutex_unlock(&bd
->ops_lock
);
297 backlight_generate_event(bd
, reason
);
299 EXPORT_SYMBOL(backlight_force_update
);
302 * backlight_device_register - create and register a new object of
303 * backlight_device class.
304 * @name: the name of the new object(must be the same as the name of the
305 * respective framebuffer device).
306 * @parent: a pointer to the parent device
307 * @devdata: an optional pointer to be stored for private driver use. The
308 * methods may retrieve it by using bl_get_data(bd).
309 * @ops: the backlight operations structure.
311 * Creates and registers new backlight device. Returns either an
312 * ERR_PTR() or a pointer to the newly allocated device.
314 struct backlight_device
*backlight_device_register(const char *name
,
315 struct device
*parent
, void *devdata
, const struct backlight_ops
*ops
,
316 const struct backlight_properties
*props
)
318 struct backlight_device
*new_bd
;
321 pr_debug("backlight_device_register: name=%s\n", name
);
323 new_bd
= kzalloc(sizeof(struct backlight_device
), GFP_KERNEL
);
325 return ERR_PTR(-ENOMEM
);
327 mutex_init(&new_bd
->update_lock
);
328 mutex_init(&new_bd
->ops_lock
);
330 new_bd
->dev
.class = backlight_class
;
331 new_bd
->dev
.parent
= parent
;
332 new_bd
->dev
.release
= bl_device_release
;
333 dev_set_name(&new_bd
->dev
, "%s", name
);
334 dev_set_drvdata(&new_bd
->dev
, devdata
);
336 /* Set default properties */
338 memcpy(&new_bd
->props
, props
,
339 sizeof(struct backlight_properties
));
340 if (props
->type
<= 0 || props
->type
>= BACKLIGHT_TYPE_MAX
) {
341 WARN(1, "%s: invalid backlight type", name
);
342 new_bd
->props
.type
= BACKLIGHT_RAW
;
345 new_bd
->props
.type
= BACKLIGHT_RAW
;
348 rc
= device_register(&new_bd
->dev
);
350 put_device(&new_bd
->dev
);
354 rc
= backlight_register_fb(new_bd
);
356 device_unregister(&new_bd
->dev
);
362 #ifdef CONFIG_PMAC_BACKLIGHT
363 mutex_lock(&pmac_backlight_mutex
);
365 pmac_backlight
= new_bd
;
366 mutex_unlock(&pmac_backlight_mutex
);
369 mutex_lock(&backlight_dev_list_mutex
);
370 list_add(&new_bd
->entry
, &backlight_dev_list
);
371 mutex_unlock(&backlight_dev_list_mutex
);
375 EXPORT_SYMBOL(backlight_device_register
);
377 bool backlight_device_registered(enum backlight_type type
)
380 struct backlight_device
*bd
;
382 mutex_lock(&backlight_dev_list_mutex
);
383 list_for_each_entry(bd
, &backlight_dev_list
, entry
) {
384 if (bd
->props
.type
== type
) {
389 mutex_unlock(&backlight_dev_list_mutex
);
393 EXPORT_SYMBOL(backlight_device_registered
);
396 * backlight_device_unregister - unregisters a backlight device object.
397 * @bd: the backlight device object to be unregistered and freed.
399 * Unregisters a previously registered via backlight_device_register object.
401 void backlight_device_unregister(struct backlight_device
*bd
)
406 mutex_lock(&backlight_dev_list_mutex
);
407 list_del(&bd
->entry
);
408 mutex_unlock(&backlight_dev_list_mutex
);
410 #ifdef CONFIG_PMAC_BACKLIGHT
411 mutex_lock(&pmac_backlight_mutex
);
412 if (pmac_backlight
== bd
)
413 pmac_backlight
= NULL
;
414 mutex_unlock(&pmac_backlight_mutex
);
416 mutex_lock(&bd
->ops_lock
);
418 mutex_unlock(&bd
->ops_lock
);
420 backlight_unregister_fb(bd
);
421 device_unregister(&bd
->dev
);
423 EXPORT_SYMBOL(backlight_device_unregister
);
425 static void devm_backlight_device_release(struct device
*dev
, void *res
)
427 struct backlight_device
*backlight
= *(struct backlight_device
**)res
;
429 backlight_device_unregister(backlight
);
432 static int devm_backlight_device_match(struct device
*dev
, void *res
,
435 struct backlight_device
**r
= res
;
441 * devm_backlight_device_register - resource managed backlight_device_register()
442 * @dev: the device to register
443 * @name: the name of the device
444 * @parent: a pointer to the parent device
445 * @devdata: an optional pointer to be stored for private driver use
446 * @ops: the backlight operations structure
447 * @props: the backlight properties
449 * @return a struct backlight on success, or an ERR_PTR on error
451 * Managed backlight_device_register(). The backlight_device returned
452 * from this function are automatically freed on driver detach.
453 * See backlight_device_register() for more information.
455 struct backlight_device
*devm_backlight_device_register(struct device
*dev
,
456 const char *name
, struct device
*parent
, void *devdata
,
457 const struct backlight_ops
*ops
,
458 const struct backlight_properties
*props
)
460 struct backlight_device
**ptr
, *backlight
;
462 ptr
= devres_alloc(devm_backlight_device_release
, sizeof(*ptr
),
465 return ERR_PTR(-ENOMEM
);
467 backlight
= backlight_device_register(name
, parent
, devdata
, ops
,
469 if (!IS_ERR(backlight
)) {
471 devres_add(dev
, ptr
);
478 EXPORT_SYMBOL(devm_backlight_device_register
);
481 * devm_backlight_device_unregister - resource managed backlight_device_unregister()
482 * @dev: the device to unregister
483 * @bd: the backlight device to unregister
485 * Deallocated a backlight allocated with devm_backlight_device_register().
486 * Normally this function will not need to be called and the resource management
487 * code will ensure that the resource is freed.
489 void devm_backlight_device_unregister(struct device
*dev
,
490 struct backlight_device
*bd
)
494 rc
= devres_release(dev
, devm_backlight_device_release
,
495 devm_backlight_device_match
, bd
);
498 EXPORT_SYMBOL(devm_backlight_device_unregister
);
501 static int of_parent_match(struct device
*dev
, const void *data
)
503 return dev
->parent
&& dev
->parent
->of_node
== data
;
507 * of_find_backlight_by_node() - find backlight device by device-tree node
508 * @node: device-tree node of the backlight device
510 * Returns a pointer to the backlight device corresponding to the given DT
511 * node or NULL if no such backlight device exists or if the device hasn't
514 * This function obtains a reference on the backlight device and it is the
515 * caller's responsibility to drop the reference by calling put_device() on
516 * the backlight device's .dev field.
518 struct backlight_device
*of_find_backlight_by_node(struct device_node
*node
)
522 dev
= class_find_device(backlight_class
, NULL
, node
, of_parent_match
);
524 return dev
? to_backlight_device(dev
) : NULL
;
526 EXPORT_SYMBOL(of_find_backlight_by_node
);
529 static void __exit
backlight_class_exit(void)
531 class_destroy(backlight_class
);
534 static int __init
backlight_class_init(void)
536 backlight_class
= class_create(THIS_MODULE
, "backlight");
537 if (IS_ERR(backlight_class
)) {
538 pr_warn("Unable to create backlight class; errno = %ld\n",
539 PTR_ERR(backlight_class
));
540 return PTR_ERR(backlight_class
);
543 backlight_class
->dev_groups
= bl_device_groups
;
544 backlight_class
->pm
= &backlight_class_dev_pm_ops
;
545 INIT_LIST_HEAD(&backlight_dev_list
);
546 mutex_init(&backlight_dev_list_mutex
);
551 * if this is compiled into the kernel, we need to ensure that the
552 * class is registered before users of the class try to register lcd's
554 postcore_initcall(backlight_class_init
);
555 module_exit(backlight_class_exit
);
557 MODULE_LICENSE("GPL");
558 MODULE_AUTHOR("Jamey Hicks <jamey.hicks@hp.com>, Andrew Zabolotny <zap@homelink.ru>");
559 MODULE_DESCRIPTION("Backlight Lowlevel Control Abstraction");