[GitHub/mt8127/android_kernel_alcatel_ttab.git] / drivers / video / backlight / backlight.c

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

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#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>
#include <linux/slab.h>

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

static const char *const backlight_types[] = {
	[BACKLIGHT_RAW] = "raw",
	[BACKLIGHT_PLATFORM] = "platform",
	[BACKLIGHT_FIRMWARE] = "firmware",
};

#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(bd, 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);
	sysfs_notify(&bd->dev.kobj, NULL, "actual_brightness");
}

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

	rc = -ENXIO;
	mutex_lock(&bd->ops_lock);
	if (bd->ops) {
		pr_debug("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 = kstrtoul(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("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_type(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct backlight_device *bd = to_backlight_device(dev);

	return sprintf(buf, "%s\n", backlight_types[bd->props.type]);
}

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);

	mutex_lock(&bd->ops_lock);
	if (bd->ops && bd->ops->options & BL_CORE_SUSPENDRESUME) {
		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);

	mutex_lock(&bd->ops_lock);
	if (bd->ops && bd->ops->options & BL_CORE_SUSPENDRESUME) {
		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(type, 0444, backlight_show_type, 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, const struct backlight_ops *ops,
	const struct backlight_properties *props)
{
	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);

	/* Set default properties */
	if (props) {
		memcpy(&new_bd->props, props,
		       sizeof(struct backlight_properties));
		if (props->type <= 0 || props->type >= BACKLIGHT_TYPE_MAX) {
			WARN(1, "%s: invalid backlight type", name);
			new_bd->props.type = BACKLIGHT_RAW;
		}
	} else {
		new_bd->props.type = BACKLIGHT_RAW;
	}

	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);

#ifdef CONFIG_OF
static int of_parent_match(struct device *dev, const void *data)
{
	return dev->parent && dev->parent->of_node == data;
}

/**
 * of_find_backlight_by_node() - find backlight device by device-tree node
 * @node: device-tree node of the backlight device
 *
 * Returns a pointer to the backlight device corresponding to the given DT
 * node or NULL if no such backlight device exists or if the device hasn't
 * been probed yet.
 *
 * This function obtains a reference on the backlight device and it is the
 * caller's responsibility to drop the reference by calling put_device() on
 * the backlight device's .dev field.
 */
struct backlight_device *of_find_backlight_by_node(struct device_node *node)
{
	struct device *dev;

	dev = class_find_device(backlight_class, NULL, node, of_parent_match);

	return dev ? to_backlight_device(dev) : NULL;
}
EXPORT_SYMBOL(of_find_backlight_by_node);
#endif

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)) {
		pr_warn("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
35f96162 JH	8	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
35f96162 JH	9
1da177e4 LT	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>
	17	#include <linux/fb.h>
5a0e3ad6	18	#include <linux/slab.h>
1da177e4	19
321709c5 RP	20	#ifdef CONFIG_PMAC_BACKLIGHT
	21	#include <asm/backlight.h>
	22	#endif
3d5eeadd	23
c338bfb5	24	static const char *const backlight_types[] = {
bb7ca747 MG	25	[BACKLIGHT_RAW] = "raw",
	26	[BACKLIGHT_PLATFORM] = "platform",
	27	[BACKLIGHT_FIRMWARE] = "firmware",
	28	};
	29
3d5eeadd JS	30	#if defined(CONFIG_FB) \|\| (defined(CONFIG_FB_MODULE) && \
	31	defined(CONFIG_BACKLIGHT_CLASS_DEVICE_MODULE))
	32	/* This callback gets called when something important happens inside a
	33	* framebuffer driver. We're looking if that important event is blanking,
	34	* and if it is, we're switching backlight power as well ...
	35	*/
	36	static int fb_notifier_callback(struct notifier_block *self,
	37	unsigned long event, void *data)
	38	{
	39	struct backlight_device *bd;
	40	struct fb_event *evdata = data;
	41
	42	/* If we aren't interested in this event, skip it immediately ... */
994efacd	43	if (event != FB_EVENT_BLANK && event != FB_EVENT_CONBLANK)
3d5eeadd JS	44	return 0;
	45
	46	bd = container_of(self, struct backlight_device, fb_notif);
599a52d1 RP	47	mutex_lock(&bd->ops_lock);
	48	if (bd->ops)
	49	if (!bd->ops->check_fb \|\|
57e148b6	50	bd->ops->check_fb(bd, evdata->info)) {
599a52d1	51	bd->props.fb_blank = (int )evdata->data;
c835ee7f RP	52	if (bd->props.fb_blank == FB_BLANK_UNBLANK)
	53	bd->props.state &= ~BL_CORE_FBBLANK;
	54	else
	55	bd->props.state \|= BL_CORE_FBBLANK;
28ee086d	56	backlight_update_status(bd);
3d5eeadd	57	}
599a52d1	58	mutex_unlock(&bd->ops_lock);
3d5eeadd JS	59	return 0;
	60	}
	61
	62	static int backlight_register_fb(struct backlight_device *bd)
	63	{
	64	memset(&bd->fb_notif, 0, sizeof(bd->fb_notif));
	65	bd->fb_notif.notifier_call = fb_notifier_callback;
	66
	67	return fb_register_client(&bd->fb_notif);
	68	}
	69
	70	static void backlight_unregister_fb(struct backlight_device *bd)
	71	{
	72	fb_unregister_client(&bd->fb_notif);
	73	}
	74	#else
	75	static inline int backlight_register_fb(struct backlight_device *bd)
	76	{
	77	return 0;
	78	}
	79
	80	static inline void backlight_unregister_fb(struct backlight_device *bd)
	81	{
	82	}
	83	#endif /* CONFIG_FB */
	84
325253a6 MG	85	static void backlight_generate_event(struct backlight_device *bd,
	86	enum backlight_update_reason reason)
	87	{
	88	char *envp[2];
	89
	90	switch (reason) {
	91	case BACKLIGHT_UPDATE_SYSFS:
	92	envp[0] = "SOURCE=sysfs";
	93	break;
	94	case BACKLIGHT_UPDATE_HOTKEY:
	95	envp[0] = "SOURCE=hotkey";
	96	break;
	97	default:
	98	envp[0] = "SOURCE=unknown";
	99	break;
	100	}
	101	envp[1] = NULL;
	102	kobject_uevent_env(&bd->dev.kobj, KOBJ_CHANGE, envp);
89dfc28c	103	sysfs_notify(&bd->dev.kobj, NULL, "actual_brightness");
325253a6 MG	104	}
325253a6 MG	105
655bfd7a	106	static ssize_t backlight_show_power(struct device *dev,
66655760	107	struct device_attribute attr, char buf)
1da177e4	108	{
655bfd7a	109	struct backlight_device *bd = to_backlight_device(dev);
1da177e4	110
599a52d1	111	return sprintf(buf, "%d\n", bd->props.power);
1da177e4 LT	112	}
1da177e4 LT	113
655bfd7a RP	114	static ssize_t backlight_store_power(struct device *dev,
655bfd7a RP	115	struct device_attribute attr, const char buf, size_t count)
1da177e4	116	{
9a2c61a9	117	int rc;
655bfd7a	118	struct backlight_device *bd = to_backlight_device(dev);
9a2c61a9	119	unsigned long power;
1da177e4	120
66655760	121	rc = kstrtoul(buf, 0, &power);
9a2c61a9 PM	122	if (rc)
9a2c61a9 PM	123	return rc;
1da177e4	124
9a2c61a9	125	rc = -ENXIO;
599a52d1 RP	126	mutex_lock(&bd->ops_lock);
599a52d1 RP	127	if (bd->ops) {
35f96162	128	pr_debug("set power to %lu\n", power);
51552453 HD	129	if (bd->props.power != power) {
	130	bd->props.power = power;
	131	backlight_update_status(bd);
	132	}
1da177e4	133	rc = count;
6ca01765	134	}
599a52d1	135	mutex_unlock(&bd->ops_lock);
1da177e4 LT	136
	137	return rc;
	138	}
	139
655bfd7a RP	140	static ssize_t backlight_show_brightness(struct device *dev,
655bfd7a RP	141	struct device_attribute attr, char buf)
1da177e4	142	{
655bfd7a	143	struct backlight_device *bd = to_backlight_device(dev);
1da177e4	144
599a52d1	145	return sprintf(buf, "%d\n", bd->props.brightness);
1da177e4 LT	146	}
1da177e4 LT	147
655bfd7a RP	148	static ssize_t backlight_store_brightness(struct device *dev,
655bfd7a RP	149	struct device_attribute attr, const char buf, size_t count)
1da177e4	150	{
9a2c61a9	151	int rc;
655bfd7a	152	struct backlight_device *bd = to_backlight_device(dev);
9a2c61a9	153	unsigned long brightness;
1da177e4	154
66655760	155	rc = kstrtoul(buf, 0, &brightness);
9a2c61a9 PM	156	if (rc)
	157	return rc;
	158
	159	rc = -ENXIO;
1da177e4	160
599a52d1 RP	161	mutex_lock(&bd->ops_lock);
	162	if (bd->ops) {
	163	if (brightness > bd->props.max_brightness)
6ca01765 RP	164	rc = -EINVAL;
6ca01765 RP	165	else {
35f96162	166	pr_debug("set brightness to %lu\n", brightness);
9be1df98 ZR	167	bd->props.brightness = brightness;
9be1df98 ZR	168	backlight_update_status(bd);
6ca01765 RP	169	rc = count;
	170	}
	171	}
599a52d1	172	mutex_unlock(&bd->ops_lock);
1da177e4	173
325253a6 MG	174	backlight_generate_event(bd, BACKLIGHT_UPDATE_SYSFS);
325253a6 MG	175
1da177e4 LT	176	return rc;
	177	}
	178
bb7ca747 MG	179	static ssize_t backlight_show_type(struct device *dev,
	180	struct device_attribute attr, char buf)
	181	{
	182	struct backlight_device *bd = to_backlight_device(dev);
	183
	184	return sprintf(buf, "%s\n", backlight_types[bd->props.type]);
	185	}
	186
655bfd7a RP	187	static ssize_t backlight_show_max_brightness(struct device *dev,
655bfd7a RP	188	struct device_attribute attr, char buf)
1da177e4	189	{
655bfd7a	190	struct backlight_device *bd = to_backlight_device(dev);
1da177e4	191
599a52d1	192	return sprintf(buf, "%d\n", bd->props.max_brightness);
6ca01765 RP	193	}
6ca01765 RP	194
655bfd7a RP	195	static ssize_t backlight_show_actual_brightness(struct device *dev,
655bfd7a RP	196	struct device_attribute attr, char buf)
6ca01765 RP	197	{
6ca01765 RP	198	int rc = -ENXIO;
655bfd7a	199	struct backlight_device *bd = to_backlight_device(dev);
6ca01765	200
599a52d1 RP	201	mutex_lock(&bd->ops_lock);
	202	if (bd->ops && bd->ops->get_brightness)
	203	rc = sprintf(buf, "%d\n", bd->ops->get_brightness(bd));
	204	mutex_unlock(&bd->ops_lock);
1da177e4 LT	205
	206	return rc;
	207	}
	208
0ad90efd	209	static struct class *backlight_class;
655bfd7a	210
c835ee7f RP	211	static int backlight_suspend(struct device *dev, pm_message_t state)
	212	{
	213	struct backlight_device *bd = to_backlight_device(dev);
	214
d1d73578 UKK	215	mutex_lock(&bd->ops_lock);
d1d73578 UKK	216	if (bd->ops && bd->ops->options & BL_CORE_SUSPENDRESUME) {
c835ee7f RP	217	bd->props.state \|= BL_CORE_SUSPENDED;
c835ee7f RP	218	backlight_update_status(bd);
c835ee7f	219	}
d1d73578	220	mutex_unlock(&bd->ops_lock);
c835ee7f RP	221
	222	return 0;
	223	}
	224
	225	static int backlight_resume(struct device *dev)
	226	{
	227	struct backlight_device *bd = to_backlight_device(dev);
	228
d1d73578 UKK	229	mutex_lock(&bd->ops_lock);
d1d73578 UKK	230	if (bd->ops && bd->ops->options & BL_CORE_SUSPENDRESUME) {
c835ee7f RP	231	bd->props.state &= ~BL_CORE_SUSPENDED;
c835ee7f RP	232	backlight_update_status(bd);
c835ee7f	233	}
d1d73578	234	mutex_unlock(&bd->ops_lock);
c835ee7f RP	235
	236	return 0;
	237	}
	238
655bfd7a	239	static void bl_device_release(struct device *dev)
1da177e4 LT	240	{
	241	struct backlight_device *bd = to_backlight_device(dev);
	242	kfree(bd);
	243	}
	244
655bfd7a RP	245	static struct device_attribute bl_device_attributes[] = {
	246	__ATTR(bl_power, 0644, backlight_show_power, backlight_store_power),
	247	__ATTR(brightness, 0644, backlight_show_brightness,
6ca01765	248	backlight_store_brightness),
655bfd7a	249	__ATTR(actual_brightness, 0444, backlight_show_actual_brightness,
6ca01765	250	NULL),
655bfd7a	251	__ATTR(max_brightness, 0444, backlight_show_max_brightness, NULL),
bb7ca747	252	__ATTR(type, 0444, backlight_show_type, NULL),
655bfd7a	253	__ATTR_NULL,
1da177e4 LT	254	};
1da177e4 LT	255
325253a6 MG	256	/**
	257	* backlight_force_update - tell the backlight subsystem that hardware state
	258	* has changed
	259	* @bd: the backlight device to update
	260	*
	261	* Updates the internal state of the backlight in response to a hardware event,
	262	* and generate a uevent to notify userspace
	263	*/
	264	void backlight_force_update(struct backlight_device *bd,
	265	enum backlight_update_reason reason)
	266	{
	267	mutex_lock(&bd->ops_lock);
	268	if (bd->ops && bd->ops->get_brightness)
	269	bd->props.brightness = bd->ops->get_brightness(bd);
	270	mutex_unlock(&bd->ops_lock);
	271	backlight_generate_event(bd, reason);
	272	}
	273	EXPORT_SYMBOL(backlight_force_update);
	274
1da177e4 LT	275	/**
	276	* backlight_device_register - create and register a new object of
	277	* backlight_device class.
	278	* @name: the name of the new object(must be the same as the name of the
	279	* respective framebuffer device).
f6ec2d96	280	* @parent: a pointer to the parent device
655bfd7a RP	281	* @devdata: an optional pointer to be stored for private driver use. The
655bfd7a RP	282	* methods may retrieve it by using bl_get_data(bd).
599a52d1	283	* @ops: the backlight operations structure.
1da177e4	284	*
655bfd7a	285	* Creates and registers new backlight device. Returns either an
1da177e4 LT	286	* ERR_PTR() or a pointer to the newly allocated device.
1da177e4 LT	287	*/
519ab5f2	288	struct backlight_device backlight_device_register(const char name,
a19a6ee6 MG	289	struct device parent, void devdata, const struct backlight_ops *ops,
a19a6ee6 MG	290	const struct backlight_properties *props)
1da177e4	291	{
1da177e4	292	struct backlight_device *new_bd;
655bfd7a	293	int rc;
1da177e4	294
655bfd7a	295	pr_debug("backlight_device_register: name=%s\n", name);
1da177e4	296
599a52d1	297	new_bd = kzalloc(sizeof(struct backlight_device), GFP_KERNEL);
90968e8e	298	if (!new_bd)
10ad1b73	299	return ERR_PTR(-ENOMEM);
1da177e4	300
28ee086d	301	mutex_init(&new_bd->update_lock);
599a52d1	302	mutex_init(&new_bd->ops_lock);
1da177e4	303
655bfd7a RP	304	new_bd->dev.class = backlight_class;
	305	new_bd->dev.parent = parent;
	306	new_bd->dev.release = bl_device_release;
64dba9a9	307	dev_set_name(&new_bd->dev, name);
655bfd7a RP	308	dev_set_drvdata(&new_bd->dev, devdata);
655bfd7a RP	309
a19a6ee6	310	/* Set default properties */
bb7ca747	311	if (props) {
a19a6ee6 MG	312	memcpy(&new_bd->props, props,
a19a6ee6 MG	313	sizeof(struct backlight_properties));
bb7ca747 MG	314	if (props->type <= 0 \|\| props->type >= BACKLIGHT_TYPE_MAX) {
	315	WARN(1, "%s: invalid backlight type", name);
	316	new_bd->props.type = BACKLIGHT_RAW;
	317	}
	318	} else {
	319	new_bd->props.type = BACKLIGHT_RAW;
	320	}
a19a6ee6	321
655bfd7a	322	rc = device_register(&new_bd->dev);
90968e8e	323	if (rc) {
2fd5a154	324	kfree(new_bd);
1da177e4 LT	325	return ERR_PTR(rc);
	326	}
	327
3d5eeadd	328	rc = backlight_register_fb(new_bd);
2fd5a154	329	if (rc) {
655bfd7a	330	device_unregister(&new_bd->dev);
2fd5a154 DT	331	return ERR_PTR(rc);
	332	}
	333
655bfd7a	334	new_bd->ops = ops;
1da177e4	335
321709c5 RP	336	#ifdef CONFIG_PMAC_BACKLIGHT
	337	mutex_lock(&pmac_backlight_mutex);
	338	if (!pmac_backlight)
	339	pmac_backlight = new_bd;
	340	mutex_unlock(&pmac_backlight_mutex);
	341	#endif
	342
1da177e4 LT	343	return new_bd;
	344	}
	345	EXPORT_SYMBOL(backlight_device_register);
	346
	347	/**
	348	* backlight_device_unregister - unregisters a backlight device object.
	349	* @bd: the backlight device object to be unregistered and freed.
	350	*
	351	* Unregisters a previously registered via backlight_device_register object.
	352	*/
	353	void backlight_device_unregister(struct backlight_device *bd)
	354	{
1da177e4 LT	355	if (!bd)
	356	return;
	357
321709c5 RP	358	#ifdef CONFIG_PMAC_BACKLIGHT
	359	mutex_lock(&pmac_backlight_mutex);
	360	if (pmac_backlight == bd)
	361	pmac_backlight = NULL;
	362	mutex_unlock(&pmac_backlight_mutex);
	363	#endif
599a52d1 RP	364	mutex_lock(&bd->ops_lock);
	365	bd->ops = NULL;
	366	mutex_unlock(&bd->ops_lock);
1da177e4	367
3d5eeadd	368	backlight_unregister_fb(bd);
655bfd7a	369	device_unregister(&bd->dev);
1da177e4 LT	370	}
	371	EXPORT_SYMBOL(backlight_device_unregister);
	372
762a936f	373	#ifdef CONFIG_OF
3213f631	374	static int of_parent_match(struct device dev, const void data)
762a936f TR	375	{
	376	return dev->parent && dev->parent->of_node == data;
	377	}
	378
	379	/**
	380	* of_find_backlight_by_node() - find backlight device by device-tree node
	381	* @node: device-tree node of the backlight device
	382	*
	383	* Returns a pointer to the backlight device corresponding to the given DT
	384	* node or NULL if no such backlight device exists or if the device hasn't
	385	* been probed yet.
	386	*
	387	* This function obtains a reference on the backlight device and it is the
	388	* caller's responsibility to drop the reference by calling put_device() on
	389	* the backlight device's .dev field.
	390	*/
	391	struct backlight_device of_find_backlight_by_node(struct device_node node)
	392	{
	393	struct device *dev;
	394
	395	dev = class_find_device(backlight_class, NULL, node, of_parent_match);
	396
	397	return dev ? to_backlight_device(dev) : NULL;
	398	}
	399	EXPORT_SYMBOL(of_find_backlight_by_node);
	400	#endif
	401
1da177e4 LT	402	static void __exit backlight_class_exit(void)
1da177e4 LT	403	{
655bfd7a	404	class_destroy(backlight_class);
1da177e4 LT	405	}
	406
	407	static int __init backlight_class_init(void)
	408	{
655bfd7a RP	409	backlight_class = class_create(THIS_MODULE, "backlight");
655bfd7a RP	410	if (IS_ERR(backlight_class)) {
35f96162 JH	411	pr_warn("Unable to create backlight class; errno = %ld\n",
35f96162 JH	412	PTR_ERR(backlight_class));
655bfd7a RP	413	return PTR_ERR(backlight_class);
	414	}
	415
	416	backlight_class->dev_attrs = bl_device_attributes;
c835ee7f RP	417	backlight_class->suspend = backlight_suspend;
c835ee7f RP	418	backlight_class->resume = backlight_resume;
655bfd7a	419	return 0;
1da177e4 LT	420	}
	421
	422	/*
	423	* if this is compiled into the kernel, we need to ensure that the
	424	* class is registered before users of the class try to register lcd's
	425	*/
	426	postcore_initcall(backlight_class_init);
	427	module_exit(backlight_class_exit);
	428
	429	MODULE_LICENSE("GPL");
	430	MODULE_AUTHOR("Jamey Hicks <jamey.hicks@hp.com>, Andrew Zabolotny <zap@homelink.ru>");
	431	MODULE_DESCRIPTION("Backlight Lowlevel Control Abstraction");