[mirror_ubuntu-jammy-kernel.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>

/**
 * 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 fb_info;

/**
 * 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 *);

	/**
	 * @check_fb: Check the framebuffer device.
	 *
	 * Check if given framebuffer device is the one bound to this backlight.
	 * This operation is optional and if not implemented it is assumed that the
	 * fbdev is always the one bound to the backlight.
	 *
	 * RETURNS:
	 *
	 * If info is NULL or the info matches the fbdev bound to the backlight return true.
	 * If info does not match the fbdev bound to the backlight return false.
	 */
	int (*check_fb)(struct backlight_device *bd, struct fb_info *info);
};

/**
 * 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;

	/**
	 * @fb_blank: The power state from the FBIOBLANK ioctl.
	 *
	 * When the FBIOBLANK ioctl is called @fb_blank is set to the
	 * blank parameter and the update_status() operation is called.
	 *
	 * When the backlight device is enabled @fb_blank is set
	 * to FB_BLANK_UNBLANK. When the backlight device is disabled
	 * @fb_blank is set to FB_BLANK_POWERDOWN.
	 *
	 * Backlight drivers should avoid using this property. It has been
	 * replaced by state & BL_CORE_FBLANK (although most drivers should
	 * use backlight_is_blank() as the preferred means to get the blank
	 * state).
	 *
	 * fb_blank is deprecated and will be removed.
	 */
	int fb_blank;

	/**
	 * @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.fb_blank = 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.fb_blank = 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 fb_blank is not UNBLANK
 *   3) 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.fb_blank != 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 LT	15	#include <linux/notifier.h>
1da177e4 LT	16
2d15bb47 SR	17	/**
	18	* enum backlight_update_reason - what method was used to update backlight
	19	*
	20	* A driver indicates the method (reason) used for updating the backlight
	21	* when calling backlight_force_update().
	22	*/
325253a6	23	enum backlight_update_reason {
2d15bb47 SR	24	/**
	25	* @BACKLIGHT_UPDATE_HOTKEY: The backlight was updated using a hot-key.
	26	*/
325253a6	27	BACKLIGHT_UPDATE_HOTKEY,
2d15bb47 SR	28
	29	/**
	30	* @BACKLIGHT_UPDATE_SYSFS: The backlight was updated using sysfs.
	31	*/
325253a6 MG	32	BACKLIGHT_UPDATE_SYSFS,
	33	};
	34
2d15bb47 SR	35	/**
	36	* enum backlight_type - the type of backlight control
	37	*
	38	* The type of interface used to control the backlight.
	39	*/
bb7ca747	40	enum backlight_type {
2d15bb47 SR	41	/**
	42	* @BACKLIGHT_RAW:
	43	*
	44	* The backlight is controlled using hardware registers.
	45	*/
bb7ca747	46	BACKLIGHT_RAW = 1,
2d15bb47 SR	47
	48	/**
	49	* @BACKLIGHT_PLATFORM:
	50	*
	51	* The backlight is controlled using a platform-specific interface.
	52	*/
bb7ca747	53	BACKLIGHT_PLATFORM,
2d15bb47 SR	54
	55	/**
	56	* @BACKLIGHT_FIRMWARE:
	57	*
	58	* The backlight is controlled using a standard firmware interface.
	59	*/
bb7ca747	60	BACKLIGHT_FIRMWARE,
2d15bb47 SR	61
	62	/**
	63	* @BACKLIGHT_TYPE_MAX: Number of entries.
	64	*/
bb7ca747 MG	65	BACKLIGHT_TYPE_MAX,
	66	};
	67
2d15bb47 SR	68	/**
	69	* enum backlight_notification - the type of notification
	70	*
	71	* The notifications that is used for notification sent to the receiver
	72	* that registered notifications using backlight_register_notifier().
	73	*/
3cc6919b	74	enum backlight_notification {
2d15bb47 SR	75	/**
	76	* @BACKLIGHT_REGISTERED: The backlight device is registered.
	77	*/
3cc6919b	78	BACKLIGHT_REGISTERED,
2d15bb47 SR	79
	80	/**
	81	* @BACKLIGHT_UNREGISTERED: The backlight revice is unregistered.
	82	*/
3cc6919b HG	83	BACKLIGHT_UNREGISTERED,
	84	};
	85
2d15bb47 SR	86	/** enum backlight_scale - the type of scale used for brightness values
	87	*
	88	* The type of scale used for brightness values.
	89	*/
d55c028f	90	enum backlight_scale {
2d15bb47 SR	91	/**
	92	* @BACKLIGHT_SCALE_UNKNOWN: The scale is unknown.
	93	*/
d55c028f	94	BACKLIGHT_SCALE_UNKNOWN = 0,
2d15bb47 SR	95
	96	/**
	97	* @BACKLIGHT_SCALE_LINEAR: The scale is linear.
	98	*
	99	* The linear scale will increase brightness the same for each step.
	100	*/
d55c028f	101	BACKLIGHT_SCALE_LINEAR,
2d15bb47 SR	102
	103	/**
	104	* @BACKLIGHT_SCALE_NON_LINEAR: The scale is not linear.
	105	*
	106	* This is often used when the brightness values tries to adjust to
	107	* the relative perception of the eye demanding a non-linear scale.
	108	*/
d55c028f MK	109	BACKLIGHT_SCALE_NON_LINEAR,
	110	};
	111
1da177e4 LT	112	struct backlight_device;
	113	struct fb_info;
	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
	162	/**
	163	* @check_fb: Check the framebuffer device.
	164	*
	165	* Check if given framebuffer device is the one bound to this backlight.
	166	* This operation is optional and if not implemented it is assumed that the
	167	* fbdev is always the one bound to the backlight.
	168	*
	169	* RETURNS:
	170	*
	171	* If info is NULL or the info matches the fbdev bound to the backlight return true.
	172	* If info does not match the fbdev bound to the backlight return false.
	173	*/
	174	int (check_fb)(struct backlight_device bd, struct fb_info *info);
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 SR	220
	221	/**
	222	* @fb_blank: The power state from the FBIOBLANK ioctl.
	223	*
	224	* When the FBIOBLANK ioctl is called @fb_blank is set to the
	225	* blank parameter and the update_status() operation is called.
	226	*
	227	* When the backlight device is enabled @fb_blank is set
	228	* to FB_BLANK_UNBLANK. When the backlight device is disabled
	229	* @fb_blank is set to FB_BLANK_POWERDOWN.
	230	*
	231	* Backlight drivers should avoid using this property. It has been
	232	* replaced by state & BL_CORE_FBLANK (although most drivers should
	233	* use backlight_is_blank() as the preferred means to get the blank
	234	* state).
	235	*
	236	* fb_blank is deprecated and will be removed.
	237	*/
6ca01765	238	int fb_blank;
cabf1613 SR	239
	240	/**
	241	* @type: The type of backlight supported.
	242	*
	243	* The backlight type allows userspace to make appropriate
	244	* policy decisions based on the backlight type.
	245	*
	246	* This value must be set in the backlight_properties
	247	* passed to devm_backlight_device_register().
	248	*/
bb7ca747	249	enum backlight_type type;
cabf1613 SR	250
	251	/**
	252	* @state: The state of the backlight core.
	253	*
	254	* The state is a bitmask. BL_CORE_FBBLANK is set when the display
	255	* is expected to be blank. BL_CORE_SUSPENDED is set when the
	256	* driver is suspended.
	257	*
	258	* backlight drivers are expected to use backlight_is_blank()
	259	* in their update_status() operation rather than reading the
	260	* state property.
	261	*
	262	* The state is maintained by the core and drivers may not modify it.
	263	*/
c835ee7f RP	264	unsigned int state;
	265
	266	#define BL_CORE_SUSPENDED (1 << 0) /* backlight is suspended */
	267	#define BL_CORE_FBBLANK (1 << 1) /* backlight is under an fb blank event */
c835ee7f	268
cabf1613 SR	269	/**
	270	* @scale: The type of the brightness scale.
	271	*/
	272	enum backlight_scale scale;
1da177e4 LT	273	};
1da177e4 LT	274
6f10cd12 SR	275	/**
	276	* struct backlight_device - backlight device data
	277	*
	278	* This structure holds all data required by a backlight device.
	279	*/
1da177e4	280	struct backlight_device {
6f10cd12 SR	281	/**
	282	* @props: Backlight properties
	283	*/
599a52d1 RP	284	struct backlight_properties props;
599a52d1 RP	285
6f10cd12 SR	286	/**
	287	* @update_lock: The lock used when calling the update_status() operation.
	288	*
	289	* update_lock is an internal backlight lock that serialise access
	290	* to the update_status() operation. The backlight core holds the update_lock
	291	* when calling the update_status() operation. The update_lock shall not
	292	* be used by backlight drivers.
	293	*/
28ee086d	294	struct mutex update_lock;
599a52d1	295
6f10cd12 SR	296	/**
	297	* @ops_lock: The lock used around everything related to backlight_ops.
	298	*
	299	* ops_lock is an internal backlight lock that protects the ops pointer
	300	* and is used around all accesses to ops and when the operations are
	301	* invoked. The ops_lock shall not be used by backlight drivers.
	302	*/
599a52d1	303	struct mutex ops_lock;
6f10cd12 SR	304
	305	/**
	306	* @ops: Pointer to the backlight operations.
	307	*
	308	* If ops is NULL, the driver that registered this device has been unloaded,
	309	* and if class_get_devdata() points to something in the body of that driver,
	310	* it is also invalid.
	311	*/
9905a43b	312	const struct backlight_ops *ops;
599a52d1	313
6f10cd12 SR	314	/**
	315	* @fb_notif: The framebuffer notifier block
	316	*/
1da177e4	317	struct notifier_block fb_notif;
655bfd7a	318
6f10cd12 SR	319	/**
	320	* @entry: List entry of all registered backlight devices
	321	*/
5915a3db AL	322	struct list_head entry;
5915a3db AL	323
6f10cd12 SR	324	/**
	325	* @dev: Parent device.
	326	*/
655bfd7a	327	struct device dev;
a55944ca	328
6f10cd12 SR	329	/**
	330	* @fb_bl_on: The state of individual fbdev's.
	331	*
	332	* Multiple fbdev's may share one backlight device. The fb_bl_on
	333	* records the state of the individual fbdev.
	334	*/
a55944ca LY	335	bool fb_bl_on[FB_MAX];
a55944ca LY	336
6f10cd12 SR	337	/**
	338	* @use_count: The number of uses of fb_bl_on.
	339	*/
a55944ca	340	int use_count;
1da177e4 LT	341	};
1da177e4 LT	342
d160fd4e SR	343	/**
	344	* backlight_update_status - force an update of the backlight device status
	345	* @bd: the backlight device
	346	*/
cca0ba2d	347	static inline int backlight_update_status(struct backlight_device *bd)
28ee086d	348	{
cca0ba2d HH	349	int ret = -ENOENT;
cca0ba2d HH	350
28ee086d	351	mutex_lock(&bd->update_lock);
599a52d1	352	if (bd->ops && bd->ops->update_status)
cca0ba2d	353	ret = bd->ops->update_status(bd);
28ee086d	354	mutex_unlock(&bd->update_lock);
cca0ba2d HH	355
cca0ba2d HH	356	return ret;
28ee086d RP	357	}
28ee086d RP	358
5b698be0 MM	359	/**
	360	* backlight_enable - Enable backlight
	361	* @bd: the backlight device to enable
	362	*/
	363	static inline int backlight_enable(struct backlight_device *bd)
	364	{
	365	if (!bd)
	366	return 0;
	367
	368	bd->props.power = FB_BLANK_UNBLANK;
	369	bd->props.fb_blank = FB_BLANK_UNBLANK;
	370	bd->props.state &= ~BL_CORE_FBBLANK;
	371
	372	return backlight_update_status(bd);
	373	}
	374
	375	/**
	376	* backlight_disable - Disable backlight
	377	* @bd: the backlight device to disable
	378	*/
	379	static inline int backlight_disable(struct backlight_device *bd)
	380	{
	381	if (!bd)
	382	return 0;
	383
	384	bd->props.power = FB_BLANK_POWERDOWN;
	385	bd->props.fb_blank = FB_BLANK_POWERDOWN;
	386	bd->props.state \|= BL_CORE_FBBLANK;
	387
	388	return backlight_update_status(bd);
	389	}
	390
1c91b465 SR	391	/**
	392	* backlight_is_blank - Return true if display is expected to be blank
	393	* @bd: the backlight device
	394	*
	395	* Display is expected to be blank if any of these is true::
	396	*
	397	* 1) if power in not UNBLANK
	398	* 2) if fb_blank is not UNBLANK
	399	* 3) if state indicate BLANK or SUSPENDED
	400	*
	401	* Returns true if display is expected to be blank, false otherwise.
	402	*/
	403	static inline bool backlight_is_blank(const struct backlight_device *bd)
	404	{
	405	return bd->props.power != FB_BLANK_UNBLANK \|\|
	406	bd->props.fb_blank != FB_BLANK_UNBLANK \|\|
	407	bd->props.state & (BL_CORE_SUSPENDED \| BL_CORE_FBBLANK);
	408	}
	409
2144d00e SR	410	/**
	411	* backlight_get_brightness - Returns the current brightness value
	412	* @bd: the backlight device
	413	*
	414	* Returns the current brightness value, taking in consideration the current
	415	* state. If backlight_is_blank() returns true then return 0 as brightness
	416	* otherwise return the current brightness property value.
	417	*
	418	* Backlight drivers are expected to use this function in their update_status()
	419	* operation to get the brightness value.
	420	*/
	421	static inline int backlight_get_brightness(const struct backlight_device *bd)
	422	{
	423	if (backlight_is_blank(bd))
	424	return 0;
	425	else
	426	return bd->props.brightness;
	427	}
	428
9c4aa311 SR	429	struct backlight_device *
	430	backlight_device_register(const char name, struct device dev, void *devdata,
	431	const struct backlight_ops *ops,
	432	const struct backlight_properties *props);
	433	struct backlight_device *
	434	devm_backlight_device_register(struct device dev, const char name,
	435	struct device parent, void devdata,
	436	const struct backlight_ops *ops,
	437	const struct backlight_properties *props);
	438	void backlight_device_unregister(struct backlight_device *bd);
	439	void devm_backlight_device_unregister(struct device *dev,
	440	struct backlight_device *bd);
	441	void backlight_force_update(struct backlight_device *bd,
	442	enum backlight_update_reason reason);
	443	int backlight_register_notifier(struct notifier_block *nb);
	444	int backlight_unregister_notifier(struct notifier_block *nb);
479da1f5	445	struct backlight_device backlight_device_get_by_name(const char name);
9c4aa311 SR	446	struct backlight_device *backlight_device_get_by_type(enum backlight_type type);
	447	int backlight_device_set_brightness(struct backlight_device *bd,
	448	unsigned long brightness);
1da177e4	449
655bfd7a RP	450	#define to_backlight_device(obj) container_of(obj, struct backlight_device, dev)
655bfd7a RP	451
d160fd4e SR	452	/**
	453	* bl_get_data - access devdata
	454	* @bl_dev: pointer to backlight device
	455	*
	456	* When a backlight device is registered the driver has the possibility
	457	* to supply a void * devdata. bl_get_data() return a pointer to the
	458	* devdata.
	459	*
	460	* RETURNS:
	461	*
	462	* pointer to devdata stored while registering the backlight device.
	463	*/
655bfd7a RP	464	static inline void * bl_get_data(struct backlight_device *bl_dev)
	465	{
	466	return dev_get_drvdata(&bl_dev->dev);
	467	}
1da177e4	468
762a936f TR	469	#ifdef CONFIG_OF
	470	struct backlight_device of_find_backlight_by_node(struct device_node node);
	471	#else
	472	static inline struct backlight_device *
	473	of_find_backlight_by_node(struct device_node *node)
	474	{
	475	return NULL;
	476	}
	477	#endif
	478
c2adda27	479	#if IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE)
2e4ef334	480	struct backlight_device devm_of_find_backlight(struct device dev);
c2adda27	481	#else
2e4ef334 MM	482	static inline struct backlight_device *
	483	devm_of_find_backlight(struct device *dev)
	484	{
	485	return NULL;
	486	}
c2adda27 MM	487	#endif
c2adda27 MM	488
1da177e4	489	#endif