[linux-2.6-block.git] / include / linux / backlight.h

/* SPDX-License-Identifier: GPL-2.0 */
/*
 * Backlight Lowlevel Control Abstraction
 *
 * Copyright (C) 2003,2004 Hewlett-Packard Company
 *
 */

#ifndef _LINUX_BACKLIGHT_H
#define _LINUX_BACKLIGHT_H

#include <linux/device.h>
#include <linux/fb.h>
#include <linux/mutex.h>
#include <linux/notifier.h>
#include <linux/types.h>

/**
 * enum backlight_update_reason - what method was used to update backlight
 *
 * A driver indicates the method (reason) used for updating the backlight
 * when calling backlight_force_update().
 */
enum backlight_update_reason {
	/**
	 * @BACKLIGHT_UPDATE_HOTKEY: The backlight was updated using a hot-key.
	 */
	BACKLIGHT_UPDATE_HOTKEY,

	/**
	 * @BACKLIGHT_UPDATE_SYSFS: The backlight was updated using sysfs.
	 */
	BACKLIGHT_UPDATE_SYSFS,
};

/**
 * enum backlight_type - the type of backlight control
 *
 * The type of interface used to control the backlight.
 */
enum backlight_type {
	/**
	 * @BACKLIGHT_RAW:
	 *
	 * The backlight is controlled using hardware registers.
	 */
	BACKLIGHT_RAW = 1,

	/**
	 * @BACKLIGHT_PLATFORM:
	 *
	 * The backlight is controlled using a platform-specific interface.
	 */
	BACKLIGHT_PLATFORM,

	/**
	 * @BACKLIGHT_FIRMWARE:
	 *
	 * The backlight is controlled using a standard firmware interface.
	 */
	BACKLIGHT_FIRMWARE,

	/**
	 * @BACKLIGHT_TYPE_MAX: Number of entries.
	 */
	BACKLIGHT_TYPE_MAX,
};

/**
 * enum backlight_notification - the type of notification
 *
 * The notifications that is used for notification sent to the receiver
 * that registered notifications using backlight_register_notifier().
 */
enum backlight_notification {
	/**
	 * @BACKLIGHT_REGISTERED: The backlight device is registered.
	 */
	BACKLIGHT_REGISTERED,

	/**
	 * @BACKLIGHT_UNREGISTERED: The backlight revice is unregistered.
	 */
	BACKLIGHT_UNREGISTERED,
};

/** enum backlight_scale - the type of scale used for brightness values
 *
 * The type of scale used for brightness values.
 */
enum backlight_scale {
	/**
	 * @BACKLIGHT_SCALE_UNKNOWN: The scale is unknown.
	 */
	BACKLIGHT_SCALE_UNKNOWN = 0,

	/**
	 * @BACKLIGHT_SCALE_LINEAR: The scale is linear.
	 *
	 * The linear scale will increase brightness the same for each step.
	 */
	BACKLIGHT_SCALE_LINEAR,

	/**
	 * @BACKLIGHT_SCALE_NON_LINEAR: The scale is not linear.
	 *
	 * This is often used when the brightness values tries to adjust to
	 * the relative perception of the eye demanding a non-linear scale.
	 */
	BACKLIGHT_SCALE_NON_LINEAR,
};

struct backlight_device;

/**
 * struct backlight_ops - backlight operations
 *
 * The backlight operations are specified when the backlight device is registered.
 */
struct backlight_ops {
	/**
	 * @options: Configure how operations are called from the core.
	 *
	 * The options parameter is used to adjust the behaviour of the core.
	 * Set BL_CORE_SUSPENDRESUME to get the update_status() operation called
	 * upon suspend and resume.
	 */
	unsigned int options;

#define BL_CORE_SUSPENDRESUME	(1 << 0)

	/**
	 * @update_status: Operation called when properties have changed.
	 *
	 * Notify the backlight driver some property has changed.
	 * The update_status operation is protected by the update_lock.
	 *
	 * The backlight driver is expected to use backlight_is_blank()
	 * to check if the display is blanked and set brightness accordingly.
	 * update_status() is called when any of the properties has changed.
	 *
	 * RETURNS:
	 *
	 * 0 on success, negative error code if any failure occurred.
	 */
	int (*update_status)(struct backlight_device *);

	/**
	 * @get_brightness: Return the current backlight brightness.
	 *
	 * The driver may implement this as a readback from the HW.
	 * This operation is optional and if not present then the current
	 * brightness property value is used.
	 *
	 * RETURNS:
	 *
	 * A brightness value which is 0 or a positive number.
	 * On failure a negative error code is returned.
	 */
	int (*get_brightness)(struct backlight_device *);

	/**
	 * @controls_device: Check against the display device
	 *
	 * Check if the backlight controls the given display device. This
	 * operation is optional and if not implemented it is assumed that
	 * the display is always the one controlled by the backlight.
	 *
	 * RETURNS:
	 *
	 * If display_dev is NULL or display_dev matches the device controlled by
	 * the backlight, return true. Otherwise return false.
	 */
	bool (*controls_device)(struct backlight_device *bd, struct device *display_dev);
};

/**
 * struct backlight_properties - backlight properties
 *
 * This structure defines all the properties of a backlight.
 */
struct backlight_properties {
	/**
	 * @brightness: The current brightness requested by the user.
	 *
	 * The backlight core makes sure the range is (0 to max_brightness)
	 * when the brightness is set via the sysfs attribute:
	 * /sys/class/backlight/<backlight>/brightness.
	 *
	 * This value can be set in the backlight_properties passed
	 * to devm_backlight_device_register() to set a default brightness
	 * value.
	 */
	int brightness;

	/**
	 * @max_brightness: The maximum brightness value.
	 *
	 * This value must be set in the backlight_properties passed to
	 * devm_backlight_device_register() and shall not be modified by the
	 * driver after registration.
	 */
	int max_brightness;

	/**
	 * @power: The current power mode.
	 *
	 * User space can configure the power mode using the sysfs
	 * attribute: /sys/class/backlight/<backlight>/bl_power
	 * When the power property is updated update_status() is called.
	 *
	 * The possible values are: (0: full on, 1 to 3: power saving
	 * modes; 4: full off), see FB_BLANK_XXX.
	 *
	 * When the backlight device is enabled @power is set
	 * to FB_BLANK_UNBLANK. When the backlight device is disabled
	 * @power is set to FB_BLANK_POWERDOWN.
	 */
	int power;

	/**
	 * @type: The type of backlight supported.
	 *
	 * The backlight type allows userspace to make appropriate
	 * policy decisions based on the backlight type.
	 *
	 * This value must be set in the backlight_properties
	 * passed to devm_backlight_device_register().
	 */
	enum backlight_type type;

	/**
	 * @state: The state of the backlight core.
	 *
	 * The state is a bitmask. BL_CORE_FBBLANK is set when the display
	 * is expected to be blank. BL_CORE_SUSPENDED is set when the
	 * driver is suspended.
	 *
	 * backlight drivers are expected to use backlight_is_blank()
	 * in their update_status() operation rather than reading the
	 * state property.
	 *
	 * The state is maintained by the core and drivers may not modify it.
	 */
	unsigned int state;

#define BL_CORE_SUSPENDED	(1 << 0)	/* backlight is suspended */
#define BL_CORE_FBBLANK		(1 << 1)	/* backlight is under an fb blank event */

	/**
	 * @scale: The type of the brightness scale.
	 */
	enum backlight_scale scale;
};

/**
 * struct backlight_device - backlight device data
 *
 * This structure holds all data required by a backlight device.
 */
struct backlight_device {
	/**
	 * @props: Backlight properties
	 */
	struct backlight_properties props;

	/**
	 * @update_lock: The lock used when calling the update_status() operation.
	 *
	 * update_lock is an internal backlight lock that serialise access
	 * to the update_status() operation. The backlight core holds the update_lock
	 * when calling the update_status() operation. The update_lock shall not
	 * be used by backlight drivers.
	 */
	struct mutex update_lock;

	/**
	 * @ops_lock: The lock used around everything related to backlight_ops.
	 *
	 * ops_lock is an internal backlight lock that protects the ops pointer
	 * and is used around all accesses to ops and when the operations are
	 * invoked. The ops_lock shall not be used by backlight drivers.
	 */
	struct mutex ops_lock;

	/**
	 * @ops: Pointer to the backlight operations.
	 *
	 * If ops is NULL, the driver that registered this device has been unloaded,
	 * and if class_get_devdata() points to something in the body of that driver,
	 * it is also invalid.
	 */
	const struct backlight_ops *ops;

	/**
	 * @fb_notif: The framebuffer notifier block
	 */
	struct notifier_block fb_notif;

	/**
	 * @entry: List entry of all registered backlight devices
	 */
	struct list_head entry;

	/**
	 * @dev: Parent device.
	 */
	struct device dev;

	/**
	 * @fb_bl_on: The state of individual fbdev's.
	 *
	 * Multiple fbdev's may share one backlight device. The fb_bl_on
	 * records the state of the individual fbdev.
	 */
	bool fb_bl_on[FB_MAX];

	/**
	 * @use_count: The number of uses of fb_bl_on.
	 */
	int use_count;
};

/**
 * backlight_update_status - force an update of the backlight device status
 * @bd: the backlight device
 */
static inline int backlight_update_status(struct backlight_device *bd)
{
	int ret = -ENOENT;

	mutex_lock(&bd->update_lock);
	if (bd->ops && bd->ops->update_status)
		ret = bd->ops->update_status(bd);
	mutex_unlock(&bd->update_lock);

	return ret;
}

/**
 * backlight_enable - Enable backlight
 * @bd: the backlight device to enable
 */
static inline int backlight_enable(struct backlight_device *bd)
{
	if (!bd)
		return 0;

	bd->props.power = FB_BLANK_UNBLANK;
	bd->props.state &= ~BL_CORE_FBBLANK;

	return backlight_update_status(bd);
}

/**
 * backlight_disable - Disable backlight
 * @bd: the backlight device to disable
 */
static inline int backlight_disable(struct backlight_device *bd)
{
	if (!bd)
		return 0;

	bd->props.power = FB_BLANK_POWERDOWN;
	bd->props.state |= BL_CORE_FBBLANK;

	return backlight_update_status(bd);
}

/**
 * backlight_is_blank - Return true if display is expected to be blank
 * @bd: the backlight device
 *
 * Display is expected to be blank if any of these is true::
 *
 *   1) if power in not UNBLANK
 *   2) if state indicate BLANK or SUSPENDED
 *
 * Returns true if display is expected to be blank, false otherwise.
 */
static inline bool backlight_is_blank(const struct backlight_device *bd)
{
	return bd->props.power != FB_BLANK_UNBLANK ||
	       bd->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK);
}

/**
 * backlight_get_brightness - Returns the current brightness value
 * @bd: the backlight device
 *
 * Returns the current brightness value, taking in consideration the current
 * state. If backlight_is_blank() returns true then return 0 as brightness
 * otherwise return the current brightness property value.
 *
 * Backlight drivers are expected to use this function in their update_status()
 * operation to get the brightness value.
 */
static inline int backlight_get_brightness(const struct backlight_device *bd)
{
	if (backlight_is_blank(bd))
		return 0;
	else
		return bd->props.brightness;
}

struct backlight_device *
backlight_device_register(const char *name, struct device *dev, void *devdata,
			  const struct backlight_ops *ops,
			  const struct backlight_properties *props);
struct backlight_device *
devm_backlight_device_register(struct device *dev, const char *name,
			       struct device *parent, void *devdata,
			       const struct backlight_ops *ops,
			       const struct backlight_properties *props);
void backlight_device_unregister(struct backlight_device *bd);
void devm_backlight_device_unregister(struct device *dev,
				      struct backlight_device *bd);
void backlight_force_update(struct backlight_device *bd,
			    enum backlight_update_reason reason);
int backlight_register_notifier(struct notifier_block *nb);
int backlight_unregister_notifier(struct notifier_block *nb);
struct backlight_device *backlight_device_get_by_name(const char *name);
struct backlight_device *backlight_device_get_by_type(enum backlight_type type);
int backlight_device_set_brightness(struct backlight_device *bd,
				    unsigned long brightness);

#define to_backlight_device(obj) container_of(obj, struct backlight_device, dev)

/**
 * bl_get_data - access devdata
 * @bl_dev: pointer to backlight device
 *
 * When a backlight device is registered the driver has the possibility
 * to supply a void * devdata. bl_get_data() return a pointer to the
 * devdata.
 *
 * RETURNS:
 *
 * pointer to devdata stored while registering the backlight device.
 */
static inline void * bl_get_data(struct backlight_device *bl_dev)
{
	return dev_get_drvdata(&bl_dev->dev);
}

#ifdef CONFIG_OF
struct backlight_device *of_find_backlight_by_node(struct device_node *node);
#else
static inline struct backlight_device *
of_find_backlight_by_node(struct device_node *node)
{
	return NULL;
}
#endif

#if IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE)
struct backlight_device *devm_of_find_backlight(struct device *dev);
#else
static inline struct backlight_device *
devm_of_find_backlight(struct device *dev)
{
	return NULL;
}
#endif

#endif
Commit	Line	Data
b2441318	1	/* SPDX-License-Identifier: GPL-2.0 */
1da177e4 LT	2	/*
	3	* Backlight Lowlevel Control Abstraction
	4	*
	5	* Copyright (C) 2003,2004 Hewlett-Packard Company
	6	*
	7	*/
	8
	9	#ifndef _LINUX_BACKLIGHT_H
	10	#define _LINUX_BACKLIGHT_H
	11
	12	#include <linux/device.h>
a55944ca	13	#include <linux/fb.h>
28ee086d	14	#include <linux/mutex.h>
1da177e4	15	#include <linux/notifier.h>
0a4be726	16	#include <linux/types.h>
1da177e4	17
2d15bb47 SR	18	/**
	19	* enum backlight_update_reason - what method was used to update backlight
	20	*
	21	* A driver indicates the method (reason) used for updating the backlight
	22	* when calling backlight_force_update().
	23	*/
325253a6	24	enum backlight_update_reason {
2d15bb47 SR	25	/**
	26	* @BACKLIGHT_UPDATE_HOTKEY: The backlight was updated using a hot-key.
	27	*/
325253a6	28	BACKLIGHT_UPDATE_HOTKEY,
2d15bb47 SR	29
	30	/**
	31	* @BACKLIGHT_UPDATE_SYSFS: The backlight was updated using sysfs.
	32	*/
325253a6 MG	33	BACKLIGHT_UPDATE_SYSFS,
	34	};
	35
2d15bb47 SR	36	/**
	37	* enum backlight_type - the type of backlight control
	38	*
	39	* The type of interface used to control the backlight.
	40	*/
bb7ca747	41	enum backlight_type {
2d15bb47 SR	42	/**
	43	* @BACKLIGHT_RAW:
	44	*
	45	* The backlight is controlled using hardware registers.
	46	*/
bb7ca747	47	BACKLIGHT_RAW = 1,
2d15bb47 SR	48
	49	/**
	50	* @BACKLIGHT_PLATFORM:
	51	*
	52	* The backlight is controlled using a platform-specific interface.
	53	*/
bb7ca747	54	BACKLIGHT_PLATFORM,
2d15bb47 SR	55
	56	/**
	57	* @BACKLIGHT_FIRMWARE:
	58	*
	59	* The backlight is controlled using a standard firmware interface.
	60	*/
bb7ca747	61	BACKLIGHT_FIRMWARE,
2d15bb47 SR	62
	63	/**
	64	* @BACKLIGHT_TYPE_MAX: Number of entries.
	65	*/
bb7ca747 MG	66	BACKLIGHT_TYPE_MAX,
	67	};
	68
2d15bb47 SR	69	/**
	70	* enum backlight_notification - the type of notification
	71	*
	72	* The notifications that is used for notification sent to the receiver
	73	* that registered notifications using backlight_register_notifier().
	74	*/
3cc6919b	75	enum backlight_notification {
2d15bb47 SR	76	/**
	77	* @BACKLIGHT_REGISTERED: The backlight device is registered.
	78	*/
3cc6919b	79	BACKLIGHT_REGISTERED,
2d15bb47 SR	80
	81	/**
	82	* @BACKLIGHT_UNREGISTERED: The backlight revice is unregistered.
	83	*/
3cc6919b HG	84	BACKLIGHT_UNREGISTERED,
	85	};
	86
2d15bb47 SR	87	/** enum backlight_scale - the type of scale used for brightness values
	88	*
	89	* The type of scale used for brightness values.
	90	*/
d55c028f	91	enum backlight_scale {
2d15bb47 SR	92	/**
	93	* @BACKLIGHT_SCALE_UNKNOWN: The scale is unknown.
	94	*/
d55c028f	95	BACKLIGHT_SCALE_UNKNOWN = 0,
2d15bb47 SR	96
	97	/**
	98	* @BACKLIGHT_SCALE_LINEAR: The scale is linear.
	99	*
	100	* The linear scale will increase brightness the same for each step.
	101	*/
d55c028f	102	BACKLIGHT_SCALE_LINEAR,
2d15bb47 SR	103
	104	/**
	105	* @BACKLIGHT_SCALE_NON_LINEAR: The scale is not linear.
	106	*
	107	* This is often used when the brightness values tries to adjust to
	108	* the relative perception of the eye demanding a non-linear scale.
	109	*/
d55c028f MK	110	BACKLIGHT_SCALE_NON_LINEAR,
	111	};
	112
1da177e4	113	struct backlight_device;
1da177e4	114
ca7c20b2 SR	115	/**
	116	* struct backlight_ops - backlight operations
	117	*
	118	* The backlight operations are specified when the backlight device is registered.
	119	*/
599a52d1	120	struct backlight_ops {
ca7c20b2 SR	121	/**
	122	* @options: Configure how operations are called from the core.
	123	*
	124	* The options parameter is used to adjust the behaviour of the core.
	125	* Set BL_CORE_SUSPENDRESUME to get the update_status() operation called
	126	* upon suspend and resume.
	127	*/
b4144e4f	128	unsigned int options;
c835ee7f RP	129
	130	#define BL_CORE_SUSPENDRESUME (1 << 0)
	131
ca7c20b2 SR	132	/**
	133	* @update_status: Operation called when properties have changed.
	134	*
	135	* Notify the backlight driver some property has changed.
	136	* The update_status operation is protected by the update_lock.
	137	*
	138	* The backlight driver is expected to use backlight_is_blank()
	139	* to check if the display is blanked and set brightness accordingly.
	140	* update_status() is called when any of the properties has changed.
	141	*
	142	* RETURNS:
	143	*
	144	* 0 on success, negative error code if any failure occurred.
	145	*/
b4144e4f	146	int (update_status)(struct backlight_device );
ca7c20b2 SR	147
	148	/**
	149	* @get_brightness: Return the current backlight brightness.
	150	*
	151	* The driver may implement this as a readback from the HW.
	152	* This operation is optional and if not present then the current
	153	* brightness property value is used.
	154	*
	155	* RETURNS:
	156	*
	157	* A brightness value which is 0 or a positive number.
	158	* On failure a negative error code is returned.
	159	*/
b4144e4f	160	int (get_brightness)(struct backlight_device );
ca7c20b2 SR	161
ca7c20b2 SR	162	/**
0a4be726	163	* @controls_device: Check against the display device
ca7c20b2	164	*
0a4be726 TZ	165	* Check if the backlight controls the given display device. This
	166	* operation is optional and if not implemented it is assumed that
	167	* the display is always the one controlled by the backlight.
ca7c20b2 SR	168	*
	169	* RETURNS:
	170	*
0a4be726 TZ	171	* If display_dev is NULL or display_dev matches the device controlled by
0a4be726 TZ	172	* the backlight, return true. Otherwise return false.
ca7c20b2	173	*/
0a4be726	174	bool (controls_device)(struct backlight_device bd, struct device *display_dev);
599a52d1	175	};
6ca01765	176
cabf1613 SR	177	/**
	178	* struct backlight_properties - backlight properties
	179	*
	180	* This structure defines all the properties of a backlight.
	181	*/
599a52d1	182	struct backlight_properties {
cabf1613 SR	183	/**
	184	* @brightness: The current brightness requested by the user.
	185	*
	186	* The backlight core makes sure the range is (0 to max_brightness)
	187	* when the brightness is set via the sysfs attribute:
	188	* /sys/class/backlight/<backlight>/brightness.
	189	*
	190	* This value can be set in the backlight_properties passed
	191	* to devm_backlight_device_register() to set a default brightness
	192	* value.
	193	*/
6ca01765	194	int brightness;
cabf1613 SR	195
	196	/**
	197	* @max_brightness: The maximum brightness value.
	198	*
	199	* This value must be set in the backlight_properties passed to
	200	* devm_backlight_device_register() and shall not be modified by the
	201	* driver after registration.
	202	*/
6ca01765	203	int max_brightness;
cabf1613 SR	204
	205	/**
	206	* @power: The current power mode.
	207	*
	208	* User space can configure the power mode using the sysfs
	209	* attribute: /sys/class/backlight/<backlight>/bl_power
	210	* When the power property is updated update_status() is called.
	211	*
	212	* The possible values are: (0: full on, 1 to 3: power saving
	213	* modes; 4: full off), see FB_BLANK_XXX.
	214	*
	215	* When the backlight device is enabled @power is set
	216	* to FB_BLANK_UNBLANK. When the backlight device is disabled
	217	* @power is set to FB_BLANK_POWERDOWN.
	218	*/
6ca01765	219	int power;
cabf1613	220
cabf1613 SR	221	/**
	222	* @type: The type of backlight supported.
	223	*
	224	* The backlight type allows userspace to make appropriate
	225	* policy decisions based on the backlight type.
	226	*
	227	* This value must be set in the backlight_properties
	228	* passed to devm_backlight_device_register().
	229	*/
bb7ca747	230	enum backlight_type type;
cabf1613 SR	231
	232	/**
	233	* @state: The state of the backlight core.
	234	*
	235	* The state is a bitmask. BL_CORE_FBBLANK is set when the display
	236	* is expected to be blank. BL_CORE_SUSPENDED is set when the
	237	* driver is suspended.
	238	*
	239	* backlight drivers are expected to use backlight_is_blank()
	240	* in their update_status() operation rather than reading the
	241	* state property.
	242	*
	243	* The state is maintained by the core and drivers may not modify it.
	244	*/
c835ee7f RP	245	unsigned int state;
	246
	247	#define BL_CORE_SUSPENDED (1 << 0) /* backlight is suspended */
	248	#define BL_CORE_FBBLANK (1 << 1) /* backlight is under an fb blank event */
c835ee7f	249
cabf1613 SR	250	/**
	251	* @scale: The type of the brightness scale.
	252	*/
	253	enum backlight_scale scale;
1da177e4 LT	254	};
1da177e4 LT	255
6f10cd12 SR	256	/**
	257	* struct backlight_device - backlight device data
	258	*
	259	* This structure holds all data required by a backlight device.
	260	*/
1da177e4	261	struct backlight_device {
6f10cd12 SR	262	/**
	263	* @props: Backlight properties
	264	*/
599a52d1 RP	265	struct backlight_properties props;
599a52d1 RP	266
6f10cd12 SR	267	/**
	268	* @update_lock: The lock used when calling the update_status() operation.
	269	*
	270	* update_lock is an internal backlight lock that serialise access
	271	* to the update_status() operation. The backlight core holds the update_lock
	272	* when calling the update_status() operation. The update_lock shall not
	273	* be used by backlight drivers.
	274	*/
28ee086d	275	struct mutex update_lock;
599a52d1	276
6f10cd12 SR	277	/**
	278	* @ops_lock: The lock used around everything related to backlight_ops.
	279	*
	280	* ops_lock is an internal backlight lock that protects the ops pointer
	281	* and is used around all accesses to ops and when the operations are
	282	* invoked. The ops_lock shall not be used by backlight drivers.
	283	*/
599a52d1	284	struct mutex ops_lock;
6f10cd12 SR	285
	286	/**
	287	* @ops: Pointer to the backlight operations.
	288	*
	289	* If ops is NULL, the driver that registered this device has been unloaded,
	290	* and if class_get_devdata() points to something in the body of that driver,
	291	* it is also invalid.
	292	*/
9905a43b	293	const struct backlight_ops *ops;
599a52d1	294
6f10cd12 SR	295	/**
	296	* @fb_notif: The framebuffer notifier block
	297	*/
1da177e4	298	struct notifier_block fb_notif;
655bfd7a	299
6f10cd12 SR	300	/**
	301	* @entry: List entry of all registered backlight devices
	302	*/
5915a3db AL	303	struct list_head entry;
5915a3db AL	304
6f10cd12 SR	305	/**
	306	* @dev: Parent device.
	307	*/
655bfd7a	308	struct device dev;
a55944ca	309
6f10cd12 SR	310	/**
	311	* @fb_bl_on: The state of individual fbdev's.
	312	*
	313	* Multiple fbdev's may share one backlight device. The fb_bl_on
	314	* records the state of the individual fbdev.
	315	*/
a55944ca LY	316	bool fb_bl_on[FB_MAX];
a55944ca LY	317
6f10cd12 SR	318	/**
	319	* @use_count: The number of uses of fb_bl_on.
	320	*/
a55944ca	321	int use_count;
1da177e4 LT	322	};
1da177e4 LT	323
d160fd4e SR	324	/**
	325	* backlight_update_status - force an update of the backlight device status
	326	* @bd: the backlight device
	327	*/
cca0ba2d	328	static inline int backlight_update_status(struct backlight_device *bd)
28ee086d	329	{
cca0ba2d HH	330	int ret = -ENOENT;
cca0ba2d HH	331
28ee086d	332	mutex_lock(&bd->update_lock);
599a52d1	333	if (bd->ops && bd->ops->update_status)
cca0ba2d	334	ret = bd->ops->update_status(bd);
28ee086d	335	mutex_unlock(&bd->update_lock);
cca0ba2d HH	336
cca0ba2d HH	337	return ret;
28ee086d RP	338	}
28ee086d RP	339
5b698be0 MM	340	/**
	341	* backlight_enable - Enable backlight
	342	* @bd: the backlight device to enable
	343	*/
	344	static inline int backlight_enable(struct backlight_device *bd)
	345	{
	346	if (!bd)
	347	return 0;
	348
	349	bd->props.power = FB_BLANK_UNBLANK;
5b698be0 MM	350	bd->props.state &= ~BL_CORE_FBBLANK;
	351
	352	return backlight_update_status(bd);
	353	}
	354
	355	/**
	356	* backlight_disable - Disable backlight
	357	* @bd: the backlight device to disable
	358	*/
	359	static inline int backlight_disable(struct backlight_device *bd)
	360	{
	361	if (!bd)
	362	return 0;
	363
	364	bd->props.power = FB_BLANK_POWERDOWN;
5b698be0 MM	365	bd->props.state \|= BL_CORE_FBBLANK;
	366
	367	return backlight_update_status(bd);
	368	}
	369
1c91b465 SR	370	/**
	371	* backlight_is_blank - Return true if display is expected to be blank
	372	* @bd: the backlight device
	373	*
	374	* Display is expected to be blank if any of these is true::
	375	*
	376	* 1) if power in not UNBLANK
4551978b	377	* 2) if state indicate BLANK or SUSPENDED
1c91b465 SR	378	*
	379	* Returns true if display is expected to be blank, false otherwise.
	380	*/
	381	static inline bool backlight_is_blank(const struct backlight_device *bd)
	382	{
	383	return bd->props.power != FB_BLANK_UNBLANK \|\|
1c91b465 SR	384	bd->props.state & (BL_CORE_SUSPENDED \| BL_CORE_FBBLANK);
	385	}
	386
2144d00e SR	387	/**
	388	* backlight_get_brightness - Returns the current brightness value
	389	* @bd: the backlight device
	390	*
	391	* Returns the current brightness value, taking in consideration the current
	392	* state. If backlight_is_blank() returns true then return 0 as brightness
	393	* otherwise return the current brightness property value.
	394	*
	395	* Backlight drivers are expected to use this function in their update_status()
	396	* operation to get the brightness value.
	397	*/
	398	static inline int backlight_get_brightness(const struct backlight_device *bd)
	399	{
	400	if (backlight_is_blank(bd))
	401	return 0;
	402	else
	403	return bd->props.brightness;
	404	}
	405
9c4aa311 SR	406	struct backlight_device *
	407	backlight_device_register(const char name, struct device dev, void *devdata,
	408	const struct backlight_ops *ops,
	409	const struct backlight_properties *props);
	410	struct backlight_device *
	411	devm_backlight_device_register(struct device dev, const char name,
	412	struct device parent, void devdata,
	413	const struct backlight_ops *ops,
	414	const struct backlight_properties *props);
	415	void backlight_device_unregister(struct backlight_device *bd);
	416	void devm_backlight_device_unregister(struct device *dev,
	417	struct backlight_device *bd);
	418	void backlight_force_update(struct backlight_device *bd,
	419	enum backlight_update_reason reason);
	420	int backlight_register_notifier(struct notifier_block *nb);
	421	int backlight_unregister_notifier(struct notifier_block *nb);
479da1f5	422	struct backlight_device backlight_device_get_by_name(const char name);
9c4aa311 SR	423	struct backlight_device *backlight_device_get_by_type(enum backlight_type type);
	424	int backlight_device_set_brightness(struct backlight_device *bd,
	425	unsigned long brightness);
1da177e4	426
655bfd7a RP	427	#define to_backlight_device(obj) container_of(obj, struct backlight_device, dev)
655bfd7a RP	428
d160fd4e SR	429	/**
	430	* bl_get_data - access devdata
	431	* @bl_dev: pointer to backlight device
	432	*
	433	* When a backlight device is registered the driver has the possibility
	434	* to supply a void * devdata. bl_get_data() return a pointer to the
	435	* devdata.
	436	*
	437	* RETURNS:
	438	*
	439	* pointer to devdata stored while registering the backlight device.
	440	*/
655bfd7a RP	441	static inline void * bl_get_data(struct backlight_device *bl_dev)
	442	{
	443	return dev_get_drvdata(&bl_dev->dev);
	444	}
1da177e4	445
762a936f TR	446	#ifdef CONFIG_OF
	447	struct backlight_device of_find_backlight_by_node(struct device_node node);
	448	#else
	449	static inline struct backlight_device *
	450	of_find_backlight_by_node(struct device_node *node)
	451	{
	452	return NULL;
	453	}
	454	#endif
	455
c2adda27	456	#if IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE)
2e4ef334	457	struct backlight_device devm_of_find_backlight(struct device dev);
c2adda27	458	#else
2e4ef334 MM	459	static inline struct backlight_device *
	460	devm_of_find_backlight(struct device *dev)
	461	{
	462	return NULL;
	463	}
c2adda27 MM	464	#endif
c2adda27 MM	465
1da177e4	466	#endif