[deliverable/linux.git] / drivers / video / backlight / backlight.c

/*
 * Backlight Lowlevel Control Abstraction
 *
 * Copyright (C) 2003,2004 Hewlett-Packard Company
 *
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/backlight.h>
#include <linux/notifier.h>
#include <linux/ctype.h>
#include <linux/err.h>
#include <linux/fb.h>

#ifdef CONFIG_PMAC_BACKLIGHT
#include <asm/backlight.h>
#endif

#if defined(CONFIG_FB) || (defined(CONFIG_FB_MODULE) && \
			   defined(CONFIG_BACKLIGHT_CLASS_DEVICE_MODULE))
/* This callback gets called when something important happens inside a
 * framebuffer driver. We're looking if that important event is blanking,
 * and if it is, we're switching backlight power as well ...
 */
static int fb_notifier_callback(struct notifier_block *self,
				unsigned long event, void *data)
{
	struct backlight_device *bd;
	struct fb_event *evdata = data;

	/* If we aren't interested in this event, skip it immediately ... */
	if (event != FB_EVENT_BLANK && event != FB_EVENT_CONBLANK)
		return 0;

	bd = container_of(self, struct backlight_device, fb_notif);
	mutex_lock(&bd->ops_lock);
	if (bd->ops)
		if (!bd->ops->check_fb ||
		    bd->ops->check_fb(evdata->info)) {
			bd->props.fb_blank = *(int *)evdata->data;
			if (bd->props.fb_blank == FB_BLANK_UNBLANK)
				bd->props.state &= ~BL_CORE_FBBLANK;
			else
				bd->props.state |= BL_CORE_FBBLANK;
			backlight_update_status(bd);
		}
	mutex_unlock(&bd->ops_lock);
	return 0;
}

static int backlight_register_fb(struct backlight_device *bd)
{
	memset(&bd->fb_notif, 0, sizeof(bd->fb_notif));
	bd->fb_notif.notifier_call = fb_notifier_callback;

	return fb_register_client(&bd->fb_notif);
}

static void backlight_unregister_fb(struct backlight_device *bd)
{
	fb_unregister_client(&bd->fb_notif);
}
#else
static inline int backlight_register_fb(struct backlight_device *bd)
{
	return 0;
}

static inline void backlight_unregister_fb(struct backlight_device *bd)
{
}
#endif /* CONFIG_FB */

static void backlight_generate_event(struct backlight_device *bd,
				     enum backlight_update_reason reason)
{
	char *envp[2];

	switch (reason) {
	case BACKLIGHT_UPDATE_SYSFS:
		envp[0] = "SOURCE=sysfs";
		break;
	case BACKLIGHT_UPDATE_HOTKEY:
		envp[0] = "SOURCE=hotkey";
		break;
	default:
		envp[0] = "SOURCE=unknown";
		break;
	}
	envp[1] = NULL;
	kobject_uevent_env(&bd->dev.kobj, KOBJ_CHANGE, envp);
}

static ssize_t backlight_show_power(struct device *dev,
		struct device_attribute *attr,char *buf)
{
	struct backlight_device *bd = to_backlight_device(dev);

	return sprintf(buf, "%d\n", bd->props.power);
}

static ssize_t backlight_store_power(struct device *dev,
		struct device_attribute *attr, const char *buf, size_t count)
{
	int rc;
	struct backlight_device *bd = to_backlight_device(dev);
	unsigned long power;

	rc = strict_strtoul(buf, 0, &power);
	if (rc)
		return rc;

	rc = -ENXIO;
	mutex_lock(&bd->ops_lock);
	if (bd->ops) {
		pr_debug("backlight: set power to %lu\n", power);
		if (bd->props.power != power) {
			bd->props.power = power;
			backlight_update_status(bd);
		}
		rc = count;
	}
	mutex_unlock(&bd->ops_lock);

	return rc;
}

static ssize_t backlight_show_brightness(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct backlight_device *bd = to_backlight_device(dev);

	return sprintf(buf, "%d\n", bd->props.brightness);
}

static ssize_t backlight_store_brightness(struct device *dev,
		struct device_attribute *attr, const char *buf, size_t count)
{
	int rc;
	struct backlight_device *bd = to_backlight_device(dev);
	unsigned long brightness;

	rc = strict_strtoul(buf, 0, &brightness);
	if (rc)
		return rc;

	rc = -ENXIO;

	mutex_lock(&bd->ops_lock);
	if (bd->ops) {
		if (brightness > bd->props.max_brightness)
			rc = -EINVAL;
		else {
			pr_debug("backlight: set brightness to %lu\n",
				 brightness);
			bd->props.brightness = brightness;
			backlight_update_status(bd);
			rc = count;
		}
	}
	mutex_unlock(&bd->ops_lock);

	backlight_generate_event(bd, BACKLIGHT_UPDATE_SYSFS);

	return rc;
}

static ssize_t backlight_show_max_brightness(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct backlight_device *bd = to_backlight_device(dev);

	return sprintf(buf, "%d\n", bd->props.max_brightness);
}

static ssize_t backlight_show_actual_brightness(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	int rc = -ENXIO;
	struct backlight_device *bd = to_backlight_device(dev);

	mutex_lock(&bd->ops_lock);
	if (bd->ops && bd->ops->get_brightness)
		rc = sprintf(buf, "%d\n", bd->ops->get_brightness(bd));
	mutex_unlock(&bd->ops_lock);

	return rc;
}

static struct class *backlight_class;

static int backlight_suspend(struct device *dev, pm_message_t state)
{
	struct backlight_device *bd = to_backlight_device(dev);

	if (bd->ops->options & BL_CORE_SUSPENDRESUME) {
		mutex_lock(&bd->ops_lock);
		bd->props.state |= BL_CORE_SUSPENDED;
		backlight_update_status(bd);
		mutex_unlock(&bd->ops_lock);
	}

	return 0;
}

static int backlight_resume(struct device *dev)
{
	struct backlight_device *bd = to_backlight_device(dev);

	if (bd->ops->options & BL_CORE_SUSPENDRESUME) {
		mutex_lock(&bd->ops_lock);
		bd->props.state &= ~BL_CORE_SUSPENDED;
		backlight_update_status(bd);
		mutex_unlock(&bd->ops_lock);
	}

	return 0;
}

static void bl_device_release(struct device *dev)
{
	struct backlight_device *bd = to_backlight_device(dev);
	kfree(bd);
}

static struct device_attribute bl_device_attributes[] = {
	__ATTR(bl_power, 0644, backlight_show_power, backlight_store_power),
	__ATTR(brightness, 0644, backlight_show_brightness,
		     backlight_store_brightness),
	__ATTR(actual_brightness, 0444, backlight_show_actual_brightness,
		     NULL),
	__ATTR(max_brightness, 0444, backlight_show_max_brightness, NULL),
	__ATTR_NULL,
};

/**
 * backlight_force_update - tell the backlight subsystem that hardware state
 *   has changed
 * @bd: the backlight device to update
 *
 * Updates the internal state of the backlight in response to a hardware event,
 * and generate a uevent to notify userspace
 */
void backlight_force_update(struct backlight_device *bd,
			    enum backlight_update_reason reason)
{
	mutex_lock(&bd->ops_lock);
	if (bd->ops && bd->ops->get_brightness)
		bd->props.brightness = bd->ops->get_brightness(bd);
	mutex_unlock(&bd->ops_lock);
	backlight_generate_event(bd, reason);
}
EXPORT_SYMBOL(backlight_force_update);

/**
 * backlight_device_register - create and register a new object of
 *   backlight_device class.
 * @name: the name of the new object(must be the same as the name of the
 *   respective framebuffer device).
 * @parent: a pointer to the parent device
 * @devdata: an optional pointer to be stored for private driver use. The
 *   methods may retrieve it by using bl_get_data(bd).
 * @ops: the backlight operations structure.
 *
 * Creates and registers new backlight device. Returns either an
 * ERR_PTR() or a pointer to the newly allocated device.
 */
struct backlight_device *backlight_device_register(const char *name,
		struct device *parent, void *devdata, struct backlight_ops *ops)
{
	struct backlight_device *new_bd;
	int rc;

	pr_debug("backlight_device_register: name=%s\n", name);

	new_bd = kzalloc(sizeof(struct backlight_device), GFP_KERNEL);
	if (!new_bd)
		return ERR_PTR(-ENOMEM);

	mutex_init(&new_bd->update_lock);
	mutex_init(&new_bd->ops_lock);

	new_bd->dev.class = backlight_class;
	new_bd->dev.parent = parent;
	new_bd->dev.release = bl_device_release;
	dev_set_name(&new_bd->dev, name);
	dev_set_drvdata(&new_bd->dev, devdata);

	rc = device_register(&new_bd->dev);
	if (rc) {
		kfree(new_bd);
		return ERR_PTR(rc);
	}

	rc = backlight_register_fb(new_bd);
	if (rc) {
		device_unregister(&new_bd->dev);
		return ERR_PTR(rc);
	}

	new_bd->ops = ops;

#ifdef CONFIG_PMAC_BACKLIGHT
	mutex_lock(&pmac_backlight_mutex);
	if (!pmac_backlight)
		pmac_backlight = new_bd;
	mutex_unlock(&pmac_backlight_mutex);
#endif

	return new_bd;
}
EXPORT_SYMBOL(backlight_device_register);

/**
 * backlight_device_unregister - unregisters a backlight device object.
 * @bd: the backlight device object to be unregistered and freed.
 *
 * Unregisters a previously registered via backlight_device_register object.
 */
void backlight_device_unregister(struct backlight_device *bd)
{
	if (!bd)
		return;

#ifdef CONFIG_PMAC_BACKLIGHT
	mutex_lock(&pmac_backlight_mutex);
	if (pmac_backlight == bd)
		pmac_backlight = NULL;
	mutex_unlock(&pmac_backlight_mutex);
#endif
	mutex_lock(&bd->ops_lock);
	bd->ops = NULL;
	mutex_unlock(&bd->ops_lock);

	backlight_unregister_fb(bd);
	device_unregister(&bd->dev);
}
EXPORT_SYMBOL(backlight_device_unregister);

static void __exit backlight_class_exit(void)
{
	class_destroy(backlight_class);
}

static int __init backlight_class_init(void)
{
	backlight_class = class_create(THIS_MODULE, "backlight");
	if (IS_ERR(backlight_class)) {
		printk(KERN_WARNING "Unable to create backlight class; errno = %ld\n",
				PTR_ERR(backlight_class));
		return PTR_ERR(backlight_class);
	}

	backlight_class->dev_attrs = bl_device_attributes;
	backlight_class->suspend = backlight_suspend;
	backlight_class->resume = backlight_resume;
	return 0;
}

/*
 * if this is compiled into the kernel, we need to ensure that the
 * class is registered before users of the class try to register lcd's
 */
postcore_initcall(backlight_class_init);
module_exit(backlight_class_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Jamey Hicks <jamey.hicks@hp.com>, Andrew Zabolotny <zap@homelink.ru>");
MODULE_DESCRIPTION("Backlight Lowlevel Control Abstraction");
Commit	Line	Data
1da177e4 LT	1	/*
	2	* Backlight Lowlevel Control Abstraction
	3	*
	4	* Copyright (C) 2003,2004 Hewlett-Packard Company
	5	*
	6	*/
	7
1da177e4 LT	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>
	15	#include <linux/fb.h>
1da177e4	16
321709c5 RP	17	#ifdef CONFIG_PMAC_BACKLIGHT
	18	#include <asm/backlight.h>
	19	#endif
3d5eeadd JS	20
	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 ...
	26	*/
	27	static int fb_notifier_callback(struct notifier_block *self,
	28	unsigned long event, void *data)
	29	{
	30	struct backlight_device *bd;
	31	struct fb_event *evdata = data;
	32
	33	/* If we aren't interested in this event, skip it immediately ... */
994efacd	34	if (event != FB_EVENT_BLANK && event != FB_EVENT_CONBLANK)
3d5eeadd JS	35	return 0;
	36
	37	bd = container_of(self, struct backlight_device, fb_notif);
599a52d1 RP	38	mutex_lock(&bd->ops_lock);
	39	if (bd->ops)
	40	if (!bd->ops->check_fb \|\|
	41	bd->ops->check_fb(evdata->info)) {
	42	bd->props.fb_blank = (int )evdata->data;
c835ee7f RP	43	if (bd->props.fb_blank == FB_BLANK_UNBLANK)
	44	bd->props.state &= ~BL_CORE_FBBLANK;
	45	else
	46	bd->props.state \|= BL_CORE_FBBLANK;
28ee086d	47	backlight_update_status(bd);
3d5eeadd	48	}
599a52d1	49	mutex_unlock(&bd->ops_lock);
3d5eeadd JS	50	return 0;
	51	}
	52
	53	static int backlight_register_fb(struct backlight_device *bd)
	54	{
	55	memset(&bd->fb_notif, 0, sizeof(bd->fb_notif));
	56	bd->fb_notif.notifier_call = fb_notifier_callback;
	57
	58	return fb_register_client(&bd->fb_notif);
	59	}
	60
	61	static void backlight_unregister_fb(struct backlight_device *bd)
	62	{
	63	fb_unregister_client(&bd->fb_notif);
	64	}
	65	#else
	66	static inline int backlight_register_fb(struct backlight_device *bd)
	67	{
	68	return 0;
	69	}
	70
	71	static inline void backlight_unregister_fb(struct backlight_device *bd)
	72	{
	73	}
	74	#endif /* CONFIG_FB */
	75
325253a6 MG	76	static void backlight_generate_event(struct backlight_device *bd,
	77	enum backlight_update_reason reason)
	78	{
	79	char *envp[2];
	80
	81	switch (reason) {
	82	case BACKLIGHT_UPDATE_SYSFS:
	83	envp[0] = "SOURCE=sysfs";
	84	break;
	85	case BACKLIGHT_UPDATE_HOTKEY:
	86	envp[0] = "SOURCE=hotkey";
	87	break;
	88	default:
	89	envp[0] = "SOURCE=unknown";
	90	break;
	91	}
	92	envp[1] = NULL;
	93	kobject_uevent_env(&bd->dev.kobj, KOBJ_CHANGE, envp);
	94	}
	95
655bfd7a RP	96	static ssize_t backlight_show_power(struct device *dev,
655bfd7a RP	97	struct device_attribute attr,char buf)
1da177e4	98	{
655bfd7a	99	struct backlight_device *bd = to_backlight_device(dev);
1da177e4	100
599a52d1	101	return sprintf(buf, "%d\n", bd->props.power);
1da177e4 LT	102	}
1da177e4 LT	103
655bfd7a RP	104	static ssize_t backlight_store_power(struct device *dev,
655bfd7a RP	105	struct device_attribute attr, const char buf, size_t count)
1da177e4	106	{
9a2c61a9	107	int rc;
655bfd7a	108	struct backlight_device *bd = to_backlight_device(dev);
9a2c61a9	109	unsigned long power;
1da177e4	110
9a2c61a9 PM	111	rc = strict_strtoul(buf, 0, &power);
	112	if (rc)
	113	return rc;
1da177e4	114
9a2c61a9	115	rc = -ENXIO;
599a52d1 RP	116	mutex_lock(&bd->ops_lock);
599a52d1 RP	117	if (bd->ops) {
9a2c61a9	118	pr_debug("backlight: set power to %lu\n", power);
51552453 HD	119	if (bd->props.power != power) {
	120	bd->props.power = power;
	121	backlight_update_status(bd);
	122	}
1da177e4	123	rc = count;
6ca01765	124	}
599a52d1	125	mutex_unlock(&bd->ops_lock);
1da177e4 LT	126
	127	return rc;
	128	}
	129
655bfd7a RP	130	static ssize_t backlight_show_brightness(struct device *dev,
655bfd7a RP	131	struct device_attribute attr, char buf)
1da177e4	132	{
655bfd7a	133	struct backlight_device *bd = to_backlight_device(dev);
1da177e4	134
599a52d1	135	return sprintf(buf, "%d\n", bd->props.brightness);
1da177e4 LT	136	}
1da177e4 LT	137
655bfd7a RP	138	static ssize_t backlight_store_brightness(struct device *dev,
655bfd7a RP	139	struct device_attribute attr, const char buf, size_t count)
1da177e4	140	{
9a2c61a9	141	int rc;
655bfd7a	142	struct backlight_device *bd = to_backlight_device(dev);
9a2c61a9	143	unsigned long brightness;
1da177e4	144
9a2c61a9 PM	145	rc = strict_strtoul(buf, 0, &brightness);
	146	if (rc)
	147	return rc;
	148
	149	rc = -ENXIO;
1da177e4	150
599a52d1 RP	151	mutex_lock(&bd->ops_lock);
	152	if (bd->ops) {
	153	if (brightness > bd->props.max_brightness)
6ca01765 RP	154	rc = -EINVAL;
6ca01765 RP	155	else {
9a2c61a9	156	pr_debug("backlight: set brightness to %lu\n",
6ca01765	157	brightness);
9be1df98 ZR	158	bd->props.brightness = brightness;
9be1df98 ZR	159	backlight_update_status(bd);
6ca01765 RP	160	rc = count;
	161	}
	162	}
599a52d1	163	mutex_unlock(&bd->ops_lock);
1da177e4	164
325253a6 MG	165	backlight_generate_event(bd, BACKLIGHT_UPDATE_SYSFS);
325253a6 MG	166
1da177e4 LT	167	return rc;
	168	}
	169
655bfd7a RP	170	static ssize_t backlight_show_max_brightness(struct device *dev,
655bfd7a RP	171	struct device_attribute attr, char buf)
1da177e4	172	{
655bfd7a	173	struct backlight_device *bd = to_backlight_device(dev);
1da177e4	174
599a52d1	175	return sprintf(buf, "%d\n", bd->props.max_brightness);
6ca01765 RP	176	}
6ca01765 RP	177
655bfd7a RP	178	static ssize_t backlight_show_actual_brightness(struct device *dev,
655bfd7a RP	179	struct device_attribute attr, char buf)
6ca01765 RP	180	{
6ca01765 RP	181	int rc = -ENXIO;
655bfd7a	182	struct backlight_device *bd = to_backlight_device(dev);
6ca01765	183
599a52d1 RP	184	mutex_lock(&bd->ops_lock);
	185	if (bd->ops && bd->ops->get_brightness)
	186	rc = sprintf(buf, "%d\n", bd->ops->get_brightness(bd));
	187	mutex_unlock(&bd->ops_lock);
1da177e4 LT	188
	189	return rc;
	190	}
	191
0ad90efd	192	static struct class *backlight_class;
655bfd7a	193
c835ee7f RP	194	static int backlight_suspend(struct device *dev, pm_message_t state)
	195	{
	196	struct backlight_device *bd = to_backlight_device(dev);
	197
	198	if (bd->ops->options & BL_CORE_SUSPENDRESUME) {
	199	mutex_lock(&bd->ops_lock);
	200	bd->props.state \|= BL_CORE_SUSPENDED;
	201	backlight_update_status(bd);
	202	mutex_unlock(&bd->ops_lock);
	203	}
	204
	205	return 0;
	206	}
	207
	208	static int backlight_resume(struct device *dev)
	209	{
	210	struct backlight_device *bd = to_backlight_device(dev);
	211
	212	if (bd->ops->options & BL_CORE_SUSPENDRESUME) {
	213	mutex_lock(&bd->ops_lock);
	214	bd->props.state &= ~BL_CORE_SUSPENDED;
	215	backlight_update_status(bd);
	216	mutex_unlock(&bd->ops_lock);
	217	}
	218
	219	return 0;
	220	}
	221
655bfd7a	222	static void bl_device_release(struct device *dev)
1da177e4 LT	223	{
	224	struct backlight_device *bd = to_backlight_device(dev);
	225	kfree(bd);
	226	}
	227
655bfd7a RP	228	static struct device_attribute bl_device_attributes[] = {
	229	__ATTR(bl_power, 0644, backlight_show_power, backlight_store_power),
	230	__ATTR(brightness, 0644, backlight_show_brightness,
6ca01765	231	backlight_store_brightness),
655bfd7a	232	__ATTR(actual_brightness, 0444, backlight_show_actual_brightness,
6ca01765	233	NULL),
655bfd7a RP	234	__ATTR(max_brightness, 0444, backlight_show_max_brightness, NULL),
655bfd7a RP	235	__ATTR_NULL,
1da177e4 LT	236	};
1da177e4 LT	237
325253a6 MG	238	/**
	239	* backlight_force_update - tell the backlight subsystem that hardware state
	240	* has changed
	241	* @bd: the backlight device to update
	242	*
	243	* Updates the internal state of the backlight in response to a hardware event,
	244	* and generate a uevent to notify userspace
	245	*/
	246	void backlight_force_update(struct backlight_device *bd,
	247	enum backlight_update_reason reason)
	248	{
	249	mutex_lock(&bd->ops_lock);
	250	if (bd->ops && bd->ops->get_brightness)
	251	bd->props.brightness = bd->ops->get_brightness(bd);
	252	mutex_unlock(&bd->ops_lock);
	253	backlight_generate_event(bd, reason);
	254	}
	255	EXPORT_SYMBOL(backlight_force_update);
	256
1da177e4 LT	257	/**
	258	* backlight_device_register - create and register a new object of
	259	* backlight_device class.
	260	* @name: the name of the new object(must be the same as the name of the
	261	* respective framebuffer device).
f6ec2d96	262	* @parent: a pointer to the parent device
655bfd7a RP	263	* @devdata: an optional pointer to be stored for private driver use. The
655bfd7a RP	264	* methods may retrieve it by using bl_get_data(bd).
599a52d1	265	* @ops: the backlight operations structure.
1da177e4	266	*
655bfd7a	267	* Creates and registers new backlight device. Returns either an
1da177e4 LT	268	* ERR_PTR() or a pointer to the newly allocated device.
1da177e4 LT	269	*/
519ab5f2	270	struct backlight_device backlight_device_register(const char name,
655bfd7a	271	struct device parent, void devdata, struct backlight_ops *ops)
1da177e4	272	{
1da177e4	273	struct backlight_device *new_bd;
655bfd7a	274	int rc;
1da177e4	275
655bfd7a	276	pr_debug("backlight_device_register: name=%s\n", name);
1da177e4	277
599a52d1	278	new_bd = kzalloc(sizeof(struct backlight_device), GFP_KERNEL);
90968e8e	279	if (!new_bd)
10ad1b73	280	return ERR_PTR(-ENOMEM);
1da177e4	281
28ee086d	282	mutex_init(&new_bd->update_lock);
599a52d1	283	mutex_init(&new_bd->ops_lock);
1da177e4	284
655bfd7a RP	285	new_bd->dev.class = backlight_class;
	286	new_bd->dev.parent = parent;
	287	new_bd->dev.release = bl_device_release;
64dba9a9	288	dev_set_name(&new_bd->dev, name);
655bfd7a RP	289	dev_set_drvdata(&new_bd->dev, devdata);
	290
	291	rc = device_register(&new_bd->dev);
90968e8e	292	if (rc) {
2fd5a154	293	kfree(new_bd);
1da177e4 LT	294	return ERR_PTR(rc);
	295	}
	296
3d5eeadd	297	rc = backlight_register_fb(new_bd);
2fd5a154	298	if (rc) {
655bfd7a	299	device_unregister(&new_bd->dev);
2fd5a154 DT	300	return ERR_PTR(rc);
	301	}
	302
655bfd7a	303	new_bd->ops = ops;
1da177e4	304
321709c5 RP	305	#ifdef CONFIG_PMAC_BACKLIGHT
	306	mutex_lock(&pmac_backlight_mutex);
	307	if (!pmac_backlight)
	308	pmac_backlight = new_bd;
	309	mutex_unlock(&pmac_backlight_mutex);
	310	#endif
	311
1da177e4 LT	312	return new_bd;
	313	}
	314	EXPORT_SYMBOL(backlight_device_register);
	315
	316	/**
	317	* backlight_device_unregister - unregisters a backlight device object.
	318	* @bd: the backlight device object to be unregistered and freed.
	319	*
	320	* Unregisters a previously registered via backlight_device_register object.
	321	*/
	322	void backlight_device_unregister(struct backlight_device *bd)
	323	{
1da177e4 LT	324	if (!bd)
	325	return;
	326
321709c5 RP	327	#ifdef CONFIG_PMAC_BACKLIGHT
	328	mutex_lock(&pmac_backlight_mutex);
	329	if (pmac_backlight == bd)
	330	pmac_backlight = NULL;
	331	mutex_unlock(&pmac_backlight_mutex);
	332	#endif
599a52d1 RP	333	mutex_lock(&bd->ops_lock);
	334	bd->ops = NULL;
	335	mutex_unlock(&bd->ops_lock);
1da177e4	336
3d5eeadd	337	backlight_unregister_fb(bd);
655bfd7a	338	device_unregister(&bd->dev);
1da177e4 LT	339	}
	340	EXPORT_SYMBOL(backlight_device_unregister);
	341
	342	static void __exit backlight_class_exit(void)
	343	{
655bfd7a	344	class_destroy(backlight_class);
1da177e4 LT	345	}
	346
	347	static int __init backlight_class_init(void)
	348	{
655bfd7a RP	349	backlight_class = class_create(THIS_MODULE, "backlight");
	350	if (IS_ERR(backlight_class)) {
	351	printk(KERN_WARNING "Unable to create backlight class; errno = %ld\n",
	352	PTR_ERR(backlight_class));
	353	return PTR_ERR(backlight_class);
	354	}
	355
	356	backlight_class->dev_attrs = bl_device_attributes;
c835ee7f RP	357	backlight_class->suspend = backlight_suspend;
c835ee7f RP	358	backlight_class->resume = backlight_resume;
655bfd7a	359	return 0;
1da177e4 LT	360	}
	361
	362	/*
	363	* if this is compiled into the kernel, we need to ensure that the
	364	* class is registered before users of the class try to register lcd's
	365	*/
	366	postcore_initcall(backlight_class_init);
	367	module_exit(backlight_class_exit);
	368
	369	MODULE_LICENSE("GPL");
	370	MODULE_AUTHOR("Jamey Hicks <jamey.hicks@hp.com>, Andrew Zabolotny <zap@homelink.ru>");
	371	MODULE_DESCRIPTION("Backlight Lowlevel Control Abstraction");