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489 lines
13 KiB
489 lines
13 KiB
/* SPDX-License-Identifier: GPL-2.0 */ |
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/* |
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* Backlight Lowlevel Control Abstraction |
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* |
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* Copyright (C) 2003,2004 Hewlett-Packard Company |
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* |
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*/ |
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#ifndef _LINUX_BACKLIGHT_H |
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#define _LINUX_BACKLIGHT_H |
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#include <linux/device.h> |
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#include <linux/fb.h> |
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#include <linux/mutex.h> |
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#include <linux/notifier.h> |
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/** |
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* enum backlight_update_reason - what method was used to update backlight |
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* |
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* A driver indicates the method (reason) used for updating the backlight |
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* when calling backlight_force_update(). |
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*/ |
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enum backlight_update_reason { |
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/** |
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* @BACKLIGHT_UPDATE_HOTKEY: The backlight was updated using a hot-key. |
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*/ |
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BACKLIGHT_UPDATE_HOTKEY, |
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/** |
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* @BACKLIGHT_UPDATE_SYSFS: The backlight was updated using sysfs. |
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*/ |
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BACKLIGHT_UPDATE_SYSFS, |
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}; |
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/** |
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* enum backlight_type - the type of backlight control |
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* |
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* The type of interface used to control the backlight. |
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*/ |
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enum backlight_type { |
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/** |
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* @BACKLIGHT_RAW: |
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* |
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* The backlight is controlled using hardware registers. |
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*/ |
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BACKLIGHT_RAW = 1, |
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/** |
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* @BACKLIGHT_PLATFORM: |
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* |
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* The backlight is controlled using a platform-specific interface. |
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*/ |
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BACKLIGHT_PLATFORM, |
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/** |
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* @BACKLIGHT_FIRMWARE: |
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* |
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* The backlight is controlled using a standard firmware interface. |
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*/ |
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BACKLIGHT_FIRMWARE, |
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/** |
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* @BACKLIGHT_TYPE_MAX: Number of entries. |
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*/ |
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BACKLIGHT_TYPE_MAX, |
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}; |
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/** |
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* enum backlight_notification - the type of notification |
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* |
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* The notifications that is used for notification sent to the receiver |
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* that registered notifications using backlight_register_notifier(). |
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*/ |
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enum backlight_notification { |
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/** |
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* @BACKLIGHT_REGISTERED: The backlight device is registered. |
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*/ |
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BACKLIGHT_REGISTERED, |
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/** |
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* @BACKLIGHT_UNREGISTERED: The backlight revice is unregistered. |
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*/ |
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BACKLIGHT_UNREGISTERED, |
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}; |
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/** enum backlight_scale - the type of scale used for brightness values |
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* |
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* The type of scale used for brightness values. |
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*/ |
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enum backlight_scale { |
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/** |
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* @BACKLIGHT_SCALE_UNKNOWN: The scale is unknown. |
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*/ |
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BACKLIGHT_SCALE_UNKNOWN = 0, |
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/** |
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* @BACKLIGHT_SCALE_LINEAR: The scale is linear. |
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* |
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* The linear scale will increase brightness the same for each step. |
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*/ |
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BACKLIGHT_SCALE_LINEAR, |
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/** |
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* @BACKLIGHT_SCALE_NON_LINEAR: The scale is not linear. |
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* |
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* This is often used when the brightness values tries to adjust to |
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* the relative perception of the eye demanding a non-linear scale. |
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*/ |
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BACKLIGHT_SCALE_NON_LINEAR, |
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}; |
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struct backlight_device; |
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struct fb_info; |
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/** |
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* struct backlight_ops - backlight operations |
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* |
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* The backlight operations are specified when the backlight device is registered. |
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*/ |
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struct backlight_ops { |
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/** |
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* @options: Configure how operations are called from the core. |
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* |
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* The options parameter is used to adjust the behaviour of the core. |
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* Set BL_CORE_SUSPENDRESUME to get the update_status() operation called |
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* upon suspend and resume. |
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*/ |
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unsigned int options; |
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#define BL_CORE_SUSPENDRESUME (1 << 0) |
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/** |
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* @update_status: Operation called when properties have changed. |
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* |
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* Notify the backlight driver some property has changed. |
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* The update_status operation is protected by the update_lock. |
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* |
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* The backlight driver is expected to use backlight_is_blank() |
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* to check if the display is blanked and set brightness accordingly. |
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* update_status() is called when any of the properties has changed. |
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* |
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* RETURNS: |
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* |
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* 0 on success, negative error code if any failure occurred. |
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*/ |
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int (*update_status)(struct backlight_device *); |
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/** |
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* @get_brightness: Return the current backlight brightness. |
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* |
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* The driver may implement this as a readback from the HW. |
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* This operation is optional and if not present then the current |
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* brightness property value is used. |
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* |
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* RETURNS: |
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* |
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* A brightness value which is 0 or a positive number. |
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* On failure a negative error code is returned. |
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*/ |
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int (*get_brightness)(struct backlight_device *); |
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/** |
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* @check_fb: Check the framebuffer device. |
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* |
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* Check if given framebuffer device is the one bound to this backlight. |
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* This operation is optional and if not implemented it is assumed that the |
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* fbdev is always the one bound to the backlight. |
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* |
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* RETURNS: |
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* |
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* If info is NULL or the info matches the fbdev bound to the backlight return true. |
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* If info does not match the fbdev bound to the backlight return false. |
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*/ |
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int (*check_fb)(struct backlight_device *bd, struct fb_info *info); |
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}; |
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/** |
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* struct backlight_properties - backlight properties |
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* |
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* This structure defines all the properties of a backlight. |
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*/ |
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struct backlight_properties { |
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/** |
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* @brightness: The current brightness requested by the user. |
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* |
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* The backlight core makes sure the range is (0 to max_brightness) |
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* when the brightness is set via the sysfs attribute: |
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* /sys/class/backlight/<backlight>/brightness. |
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* |
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* This value can be set in the backlight_properties passed |
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* to devm_backlight_device_register() to set a default brightness |
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* value. |
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*/ |
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int brightness; |
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/** |
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* @max_brightness: The maximum brightness value. |
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* |
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* This value must be set in the backlight_properties passed to |
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* devm_backlight_device_register() and shall not be modified by the |
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* driver after registration. |
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*/ |
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int max_brightness; |
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/** |
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* @power: The current power mode. |
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* |
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* User space can configure the power mode using the sysfs |
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* attribute: /sys/class/backlight/<backlight>/bl_power |
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* When the power property is updated update_status() is called. |
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* |
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* The possible values are: (0: full on, 1 to 3: power saving |
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* modes; 4: full off), see FB_BLANK_XXX. |
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* |
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* When the backlight device is enabled @power is set |
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* to FB_BLANK_UNBLANK. When the backlight device is disabled |
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* @power is set to FB_BLANK_POWERDOWN. |
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*/ |
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int power; |
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/** |
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* @fb_blank: The power state from the FBIOBLANK ioctl. |
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* |
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* When the FBIOBLANK ioctl is called @fb_blank is set to the |
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* blank parameter and the update_status() operation is called. |
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* |
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* When the backlight device is enabled @fb_blank is set |
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* to FB_BLANK_UNBLANK. When the backlight device is disabled |
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* @fb_blank is set to FB_BLANK_POWERDOWN. |
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* |
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* Backlight drivers should avoid using this property. It has been |
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* replaced by state & BL_CORE_FBLANK (although most drivers should |
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* use backlight_is_blank() as the preferred means to get the blank |
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* state). |
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* |
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* fb_blank is deprecated and will be removed. |
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*/ |
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int fb_blank; |
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/** |
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* @type: The type of backlight supported. |
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* |
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* The backlight type allows userspace to make appropriate |
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* policy decisions based on the backlight type. |
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* |
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* This value must be set in the backlight_properties |
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* passed to devm_backlight_device_register(). |
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*/ |
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enum backlight_type type; |
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/** |
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* @state: The state of the backlight core. |
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* |
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* The state is a bitmask. BL_CORE_FBBLANK is set when the display |
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* is expected to be blank. BL_CORE_SUSPENDED is set when the |
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* driver is suspended. |
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* |
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* backlight drivers are expected to use backlight_is_blank() |
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* in their update_status() operation rather than reading the |
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* state property. |
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* |
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* The state is maintained by the core and drivers may not modify it. |
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*/ |
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unsigned int state; |
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#define BL_CORE_SUSPENDED (1 << 0) /* backlight is suspended */ |
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#define BL_CORE_FBBLANK (1 << 1) /* backlight is under an fb blank event */ |
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/** |
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* @scale: The type of the brightness scale. |
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*/ |
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enum backlight_scale scale; |
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}; |
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/** |
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* struct backlight_device - backlight device data |
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* |
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* This structure holds all data required by a backlight device. |
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*/ |
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struct backlight_device { |
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/** |
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* @props: Backlight properties |
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*/ |
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struct backlight_properties props; |
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/** |
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* @update_lock: The lock used when calling the update_status() operation. |
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* |
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* update_lock is an internal backlight lock that serialise access |
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* to the update_status() operation. The backlight core holds the update_lock |
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* when calling the update_status() operation. The update_lock shall not |
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* be used by backlight drivers. |
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*/ |
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struct mutex update_lock; |
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/** |
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* @ops_lock: The lock used around everything related to backlight_ops. |
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* |
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* ops_lock is an internal backlight lock that protects the ops pointer |
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* and is used around all accesses to ops and when the operations are |
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* invoked. The ops_lock shall not be used by backlight drivers. |
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*/ |
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struct mutex ops_lock; |
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/** |
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* @ops: Pointer to the backlight operations. |
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* |
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* If ops is NULL, the driver that registered this device has been unloaded, |
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* and if class_get_devdata() points to something in the body of that driver, |
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* it is also invalid. |
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*/ |
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const struct backlight_ops *ops; |
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/** |
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* @fb_notif: The framebuffer notifier block |
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*/ |
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struct notifier_block fb_notif; |
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/** |
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* @entry: List entry of all registered backlight devices |
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*/ |
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struct list_head entry; |
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/** |
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* @dev: Parent device. |
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*/ |
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struct device dev; |
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/** |
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* @fb_bl_on: The state of individual fbdev's. |
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* |
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* Multiple fbdev's may share one backlight device. The fb_bl_on |
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* records the state of the individual fbdev. |
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*/ |
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bool fb_bl_on[FB_MAX]; |
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/** |
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* @use_count: The number of uses of fb_bl_on. |
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*/ |
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int use_count; |
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}; |
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/** |
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* backlight_update_status - force an update of the backlight device status |
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* @bd: the backlight device |
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*/ |
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static inline int backlight_update_status(struct backlight_device *bd) |
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{ |
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int ret = -ENOENT; |
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mutex_lock(&bd->update_lock); |
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if (bd->ops && bd->ops->update_status) |
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ret = bd->ops->update_status(bd); |
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mutex_unlock(&bd->update_lock); |
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return ret; |
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} |
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/** |
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* backlight_enable - Enable backlight |
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* @bd: the backlight device to enable |
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*/ |
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static inline int backlight_enable(struct backlight_device *bd) |
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{ |
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if (!bd) |
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return 0; |
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bd->props.power = FB_BLANK_UNBLANK; |
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bd->props.fb_blank = FB_BLANK_UNBLANK; |
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bd->props.state &= ~BL_CORE_FBBLANK; |
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return backlight_update_status(bd); |
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} |
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/** |
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* backlight_disable - Disable backlight |
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* @bd: the backlight device to disable |
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*/ |
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static inline int backlight_disable(struct backlight_device *bd) |
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{ |
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if (!bd) |
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return 0; |
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bd->props.power = FB_BLANK_POWERDOWN; |
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bd->props.fb_blank = FB_BLANK_POWERDOWN; |
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bd->props.state |= BL_CORE_FBBLANK; |
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return backlight_update_status(bd); |
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} |
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/** |
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* backlight_is_blank - Return true if display is expected to be blank |
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* @bd: the backlight device |
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* |
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* Display is expected to be blank if any of these is true:: |
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* |
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* 1) if power in not UNBLANK |
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* 2) if fb_blank is not UNBLANK |
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* 3) if state indicate BLANK or SUSPENDED |
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* |
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* Returns true if display is expected to be blank, false otherwise. |
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*/ |
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static inline bool backlight_is_blank(const struct backlight_device *bd) |
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{ |
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return bd->props.power != FB_BLANK_UNBLANK || |
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bd->props.fb_blank != FB_BLANK_UNBLANK || |
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bd->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK); |
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} |
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/** |
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* backlight_get_brightness - Returns the current brightness value |
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* @bd: the backlight device |
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* |
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* Returns the current brightness value, taking in consideration the current |
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* state. If backlight_is_blank() returns true then return 0 as brightness |
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* otherwise return the current brightness property value. |
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* |
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* Backlight drivers are expected to use this function in their update_status() |
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* operation to get the brightness value. |
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*/ |
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static inline int backlight_get_brightness(const struct backlight_device *bd) |
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{ |
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if (backlight_is_blank(bd)) |
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return 0; |
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else |
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return bd->props.brightness; |
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} |
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struct backlight_device * |
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backlight_device_register(const char *name, struct device *dev, void *devdata, |
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const struct backlight_ops *ops, |
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const struct backlight_properties *props); |
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struct backlight_device * |
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devm_backlight_device_register(struct device *dev, const char *name, |
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struct device *parent, void *devdata, |
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const struct backlight_ops *ops, |
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const struct backlight_properties *props); |
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void backlight_device_unregister(struct backlight_device *bd); |
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void devm_backlight_device_unregister(struct device *dev, |
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struct backlight_device *bd); |
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void backlight_force_update(struct backlight_device *bd, |
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enum backlight_update_reason reason); |
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int backlight_register_notifier(struct notifier_block *nb); |
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int backlight_unregister_notifier(struct notifier_block *nb); |
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struct backlight_device *backlight_device_get_by_name(const char *name); |
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struct backlight_device *backlight_device_get_by_type(enum backlight_type type); |
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int backlight_device_set_brightness(struct backlight_device *bd, |
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unsigned long brightness); |
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#define to_backlight_device(obj) container_of(obj, struct backlight_device, dev) |
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/** |
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* bl_get_data - access devdata |
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* @bl_dev: pointer to backlight device |
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* |
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* When a backlight device is registered the driver has the possibility |
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* to supply a void * devdata. bl_get_data() return a pointer to the |
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* devdata. |
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* |
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* RETURNS: |
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* |
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* pointer to devdata stored while registering the backlight device. |
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*/ |
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static inline void * bl_get_data(struct backlight_device *bl_dev) |
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{ |
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return dev_get_drvdata(&bl_dev->dev); |
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} |
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#ifdef CONFIG_OF |
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struct backlight_device *of_find_backlight_by_node(struct device_node *node); |
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#else |
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static inline struct backlight_device * |
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of_find_backlight_by_node(struct device_node *node) |
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{ |
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return NULL; |
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} |
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#endif |
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#if IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE) |
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struct backlight_device *devm_of_find_backlight(struct device *dev); |
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#else |
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static inline struct backlight_device * |
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devm_of_find_backlight(struct device *dev) |
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{ |
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return NULL; |
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} |
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#endif |
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#endif
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