backlight: Remove notifier

backlight_register_notifier and backlight_unregister_notifier have
been unused since commit 6cb634d0dc85 ("ACPI: video: Remove code to
unregister acpi_video backlight when

backlight: Remove notifier

backlight_register_notifier and backlight_unregister_notifier have
been unused since commit 6cb634d0dc85 ("ACPI: video: Remove code to
unregister acpi_video backlight when a native backlight registers")

With those not being called, it means that the backlight_notifier
list is always empty.

Remove the functions, the list itself and the enum used in the
notifications.

Signed-off-by: Dr. David Alan Gilbert <[email protected]>
Reviewed-by: Daniel Thompson <[email protected]>
Reviewed-by: Simona Vetter <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Lee Jones <[email protected]>

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backlight: Make backlight_class constant

Since commit 43a7206b0963 ("driver core: class: make class_register() take
a const *"), the driver core allows for struct class to be in read-only
memory, so

backlight: Make backlight_class constant

Since commit 43a7206b0963 ("driver core: class: make class_register() take
a const *"), the driver core allows for struct class to be in read-only
memory, so move the backlight_class structure to be declared at build time
placing it into read-only memory, instead of having to be dynamically
allocated at boot time.

Cc: Greg Kroah-Hartman <[email protected]>
Suggested-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Ricardo B. Marliere <[email protected]>
Reviewed-by: Daniel Thompson <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Lee Jones <[email protected]>

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backlight: Remove fb_blank from struct backlight_properties

Remove the field fb_blank from struct backlight_properties and remove
all code that still sets or reads it. Backlight blank status is now

backlight: Remove fb_blank from struct backlight_properties

Remove the field fb_blank from struct backlight_properties and remove
all code that still sets or reads it. Backlight blank status is now
tracked exclusively in struct backlight_properties.state.

The core backlight code keeps the fb_blank and state fields in sync,
but doesn't do anything else with fb_blank. Several drivers initialize
fb_blank to FB_BLANK_UNBLANK to enable the backlight. This is already
the default for the state field. So we can delete the fb_blank code
from core and drivers and rely on the state field.

Signed-off-by: Thomas Zimmermann <[email protected]>
Cc: Flavio Suligoi <[email protected]>
Cc: Nicolas Ferre <[email protected]>
Cc: Alexandre Belloni <[email protected]>
Cc: Claudiu Beznea <[email protected]>
Tested-by: Flavio Suligoi <[email protected]>
Reviewed-by: Daniel Thompson <[email protected]>
Reviewed-by: Dan Carpenter <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Lee Jones <[email protected]>

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backlight: Add controls_device callback to struct backlight_ops

Replace check_fb with controls_device in struct backlight_ops. The
new callback interface takes a Linux device instead of a framebuffe

backlight: Add controls_device callback to struct backlight_ops

Replace check_fb with controls_device in struct backlight_ops. The
new callback interface takes a Linux device instead of a framebuffer.
Resolves one of the dependencies of backlight.h on fb.h.

The few drivers that had custom implementations of check_fb can easily
use the framebuffer's Linux device instead. Update them accordingly.

Signed-off-by: Thomas Zimmermann <[email protected]>
Reviewed-by: Daniel Thompson <[email protected]>
Reviewed-by: Javier Martinez Canillas <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Lee Jones <[email protected]>

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backlight: Match backlight device against struct fb_info.bl_dev

Framebuffer drivers for devices with dedicated backlight are supposed
to set struct fb_info.bl_dev to the backlight's respective devic

backlight: Match backlight device against struct fb_info.bl_dev

Framebuffer drivers for devices with dedicated backlight are supposed
to set struct fb_info.bl_dev to the backlight's respective device. Use
the value to match backlight and framebuffer in the backlight core code.

The code first tests against struct backlight_ops.check_ops. If this
test succeeds, it performs the test against fbdev. So backlight drivers
can override the later test as before.

Fbdev's backlight support depends on CONFIG_FB_BACKLIGHT. To avoid
ifdef in the code, the new helper fb_bl_device() returns the backlight
device, or NULL if the config option has been disabled. The test in
the backlight code will then do nothing.

v4:
* declare empty fb_bl_device() as static inline
* export fb_bl_device()
v3:
* hide ifdef in fb_bl_device() (Lee)
* no if-else blocks (Andy)

Signed-off-by: Thomas Zimmermann <[email protected]>
Reviewed-by: Daniel Thompson <[email protected]>
Reviewed-by: Javier Martinez Canillas <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Lee Jones <[email protected]>

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fbdev: Split frame buffer support in FB and FB_CORE symbols

Currently the CONFIG_FB option has to be enabled even if no legacy fbdev
drivers are needed (e.g: only to have support for framebuffer con

fbdev: Split frame buffer support in FB and FB_CORE symbols

Currently the CONFIG_FB option has to be enabled even if no legacy fbdev
drivers are needed (e.g: only to have support for framebuffer consoles).

The DRM subsystem has a fbdev emulation layer, but depends on CONFIG_FB
and so it can only be enabled if that dependency is enabled as well.

That means fbdev drivers have to be explicitly disabled if users want to
enable CONFIG_FB, only to use fbcon and/or the DRM fbdev emulation layer.

This patch introduces a non-visible CONFIG_FB_CORE symbol that could be
enabled just to have core support needed for CONFIG_DRM_FBDEV_EMULATION,
allowing CONFIG_FB to be disabled (and automatically disabling all the
fbdev drivers).

Nothing from fb_backlight.o and fbmon.o is used by the DRM fbdev emulation
layer so these two objects can be compiled out when CONFIG_FB is disabled.

Signed-off-by: Javier Martinez Canillas <[email protected]>
Reviewed-by: Arnd Bergmann <[email protected]>
Tested-by: Arnd Bergmann <[email protected]>
Acked-by: Helge Deller <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]

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driver core: class: remove module * from class_create()

The module pointer in class_create() never actually did anything, and it
shouldn't have been requred to be set as a parameter even if it did
s

driver core: class: remove module * from class_create()

The module pointer in class_create() never actually did anything, and it
shouldn't have been requred to be set as a parameter even if it did
something. So just remove it and fix up all callers of the function in
the kernel tree at the same time.

Cc: "Rafael J. Wysocki" <[email protected]>
Acked-by: Benjamin Tissoires <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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backlight: backlight: Fix doc for backlight_device_get_by_name

backlight_put() has been dropped, we should call put_device() to drop
the reference taken by backlight_device_get_by_name().

Fixes: 0f

backlight: backlight: Fix doc for backlight_device_get_by_name

backlight_put() has been dropped, we should call put_device() to drop
the reference taken by backlight_device_get_by_name().

Fixes: 0f6a3256fd81 ("backlight: backlight: Drop backlight_put()")
Signed-off-by: Miaoqian Lin <[email protected]>
Reviewed-by: Daniel Thompson <[email protected]>
Signed-off-by: Lee Jones <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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backlight: backlight: Slighly simplify devm_of_find_backlight()

Use devm_add_action_or_reset() instead of devm_add_action()+hand writing
what is done in the release function, should an error occur.

backlight: backlight: Slighly simplify devm_of_find_backlight()

Use devm_add_action_or_reset() instead of devm_add_action()+hand writing
what is done in the release function, should an error occur.

This is more straightforward and saves a few lines of code.

While at it, remove a useless test in devm_backlight_release(). 'data' is
known to be not NULL when this function is called.

Signed-off-by: Christophe JAILLET <[email protected]>
Reviewed-by: Daniel Thompson <[email protected]>
Signed-off-by: Lee Jones <[email protected]>
Link: https://lore.kernel.org/r/f998a4291d865273afa0d1f85764a9ac7fbc1b64.1644738084.git.christophe.jaillet@wanadoo.fr

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backlight: Propagate errors from get_brightness()

backlight.h documents "struct backlight_ops->get_brightness()" to return
a negative errno on failure.

So far these errors have not been handled in

backlight: Propagate errors from get_brightness()

backlight.h documents "struct backlight_ops->get_brightness()" to return
a negative errno on failure.

So far these errors have not been handled in the backlight core.
This leads to negative values being exposed through sysfs although only
positive values are documented to be reported.

Signed-off-by: Thomas Weißschuh <[email protected]>
Reviewed-by: Daniel Thompson <[email protected]>
Signed-off-by: Lee Jones <[email protected]>

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video: backlight: Drop maximum brightness override for brightness zero

The note in c2adda27d202f ("video: backlight: Add of_find_backlight helper
in backlight.c") says that gpio-backlight uses brigh

video: backlight: Drop maximum brightness override for brightness zero

The note in c2adda27d202f ("video: backlight: Add of_find_backlight helper
in backlight.c") says that gpio-backlight uses brightness as power state.
This has been fixed since in ec665b756e6f7 ("backlight: gpio-backlight:
Correct initial power state handling") and other backlight drivers do not
require this workaround. Drop the workaround.

This fixes the case where e.g. pwm-backlight can perfectly well be set to
brightness 0 on boot in DT, which without this patch leads to the display
brightness to be max instead of off.

Fixes: c2adda27d202f ("video: backlight: Add of_find_backlight helper in backlight.c")
Cc: <[email protected]> # 5.4+
Cc: <[email protected]> # 4.19.x: ec665b756e6f7: backlight: gpio-backlight: Correct initial power state handling
Signed-off-by: Marek Vasut <[email protected]>
Acked-by: Noralf Trønnes <[email protected]>
Reviewed-by: Daniel Thompson <[email protected]>
Signed-off-by: Lee Jones <[email protected]>

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backlight: backlight: Make of_find_backlight static

There are no external users of of_find_backlight, as they have all
changed to use the managed version. Make of_find_backlight static to
prevent ne

backlight: backlight: Make of_find_backlight static

There are no external users of of_find_backlight, as they have all
changed to use the managed version. Make of_find_backlight static to
prevent new external users.

Signed-off-by: Sam Ravnborg <[email protected]>
Reviewed-by: Daniel Thompson <[email protected]>
Signed-off-by: Lee Jones <[email protected]>

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backlight: backlight: Drop backlight_put()

There are no external users of backlight_put(). Drop it and open code
the two users in backlight.c.

Signed-off-by: Sam Ravnborg <[email protected]>
Reviewe

backlight: backlight: Drop backlight_put()

There are no external users of backlight_put(). Drop it and open code
the two users in backlight.c.

Signed-off-by: Sam Ravnborg <[email protected]>
Reviewed-by: Daniel Thompson <[email protected]>
Signed-off-by: Lee Jones <[email protected]>

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backlight: backlight: Add overview and update existing doc

Add overview chapter to backlight.c.

Update existing kernel-doc to follow a more consistent style and drop
kernel-doc for deprecated funct

backlight: backlight: Add overview and update existing doc

Add overview chapter to backlight.c.

Update existing kernel-doc to follow a more consistent style and drop
kernel-doc for deprecated functions.

Signed-off-by: Sam Ravnborg <[email protected]>
Reviewed-by: Daniel Thompson <[email protected]>
Reviewed-by: Emil Velikov <[email protected]>
Signed-off-by: Lee Jones <[email protected]>

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backlight: backlight: Refactor fb_notifier_callback()

Increase readability of fb_notifier_callback() by removing
a few indent levels.

No functional change.

Signed-off-by: Sam Ravnborg <sam@ravnbor

backlight: backlight: Refactor fb_notifier_callback()

Increase readability of fb_notifier_callback() by removing
a few indent levels.

No functional change.

Signed-off-by: Sam Ravnborg <[email protected]>
Reviewed-by: Daniel Thompson <[email protected]>
Reviewed-by: Emil Velikov <[email protected]>
Signed-off-by: Lee Jones <[email protected]>

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backlight: backlight: Supply description for function args in existing Kerneldocs

Kerneldoc syntax is used, but not complete. Descriptions required.

Prevents warnings like:

drivers/video/backlig

backlight: backlight: Supply description for function args in existing Kerneldocs

Kerneldoc syntax is used, but not complete. Descriptions required.

Prevents warnings like:

drivers/video/backlight/backlight.c:329: warning: Function parameter or member 'reason' not described in 'backlight_force_update'
drivers/video/backlight/backlight.c:354: warning: Function parameter or member 'props' not described in 'backlight_device_register'

Cc: Bartlomiej Zolnierkiewicz <[email protected]>
Cc: Jamey Hicks <[email protected]>
Cc: Andrew Zabolotny <[email protected]>
Signed-off-by: Lee Jones <[email protected]>
Reviewed-by: Daniel Thompson <[email protected]>
Reviewed-by: Sam Ravnborg <[email protected]>
Signed-off-by: Lee Jones <[email protected]>

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backlight: Add backlight_device_get_by_name()

Add a way to lookup a backlight device based on its name.
Will be used by a USB display gadget getting the name from configfs.

Signed-off-by: Noralf Tr

backlight: Add backlight_device_get_by_name()

Add a way to lookup a backlight device based on its name.
Will be used by a USB display gadget getting the name from configfs.

Signed-off-by: Noralf Trønnes <[email protected]>
Reviewed-by: Sam Ravnborg <[email protected]>
Reviewed-by: Daniel Thompson <[email protected]>
Acked-by: Jingoo Han <[email protected]>
Signed-off-by: Lee Jones <[email protected]>

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backlight: Expose brightness curve type through sysfs

Backlight brightness curves can have different shapes. The two main
types are linear and non-linear curves. The human eye doesn't
perceive linea

backlight: Expose brightness curve type through sysfs

Backlight brightness curves can have different shapes. The two main
types are linear and non-linear curves. The human eye doesn't
perceive linearly increasing/decreasing brightness as linear (see
also 88ba95bedb79 "backlight: pwm_bl: Compute brightness of LED
linearly to human eye"), hence many backlights use non-linear (often
logarithmic) brightness curves. The type of curve currently is opaque
to userspace, so userspace often uses more or less reliable heuristics
(like the number of brightness levels) to decide whether to treat a
backlight device as linear or non-linear.

Export the type of the brightness curve via the new sysfs attribute
'scale'. The value of the attribute can be 'linear', 'non-linear' or
'unknown'. For devices that don't provide information about the scale
of their brightness curve the value of the 'scale' attribute is 'unknown'.

Signed-off-by: Matthias Kaehlcke <[email protected]>
Reviewed-by: Daniel Thompson <[email protected]>
Signed-off-by: Lee Jones <[email protected]>

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Revert "backlight/fbcon: Add FB_EVENT_CONBLANK"

This reverts commit 994efacdf9a087b52f71e620b58dfa526b0cf928.

The justification is that if hw blanking fails (i.e. fbops->fb_blank)
fails, then we st

Revert "backlight/fbcon: Add FB_EVENT_CONBLANK"

This reverts commit 994efacdf9a087b52f71e620b58dfa526b0cf928.

The justification is that if hw blanking fails (i.e. fbops->fb_blank)
fails, then we still want to shut down the backlight. Which is exactly
_not_ what fb_blank() does and so rather inconsistent if we end up
with different behaviour between fbcon and direct fbdev usage. Given
that the entire notifier maze is getting in the way anyway I figured
it's simplest to revert this not well justified commit.

v2: Add static inline to the dummy version.

Cc: Richard Purdie <[email protected]>
Signed-off-by: Daniel Vetter <[email protected]>
Reviewed-by: Sam Ravnborg <[email protected]>
Reviewed-by: Maarten Lankhorst <[email protected]>
Acked-by: Daniel Thompson <[email protected]>
Cc: Lee Jones <[email protected]>
Cc: Daniel Thompson <[email protected]>
Cc: Jingoo Han <[email protected]>
Cc: Bartlomiej Zolnierkiewicz <[email protected]>
Cc: Daniel Vetter <[email protected]>
Cc: Hans de Goede <[email protected]>
Cc: Yisheng Xie <[email protected]>
Cc: [email protected]
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]

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treewide: Add SPDX license identifier for more missed files

Add SPDX license identifiers to all files which:

- Have no license information of any form

- Have MODULE_LICENCE("GPL*") inside which

treewide: Add SPDX license identifier for more missed files

Add SPDX license identifiers to all files which:

- Have no license information of any form

- Have MODULE_LICENCE("GPL*") inside which was used in the initial
scan/conversion to ignore the file

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

GPL-2.0-only

Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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video: backlight: Add devres versions of of_find_backlight

Add devm_of_find_backlight and the corresponding release
function because some drivers use devres versions of functions
for acquiring devic

video: backlight: Add devres versions of of_find_backlight

Add devm_of_find_backlight and the corresponding release
function because some drivers use devres versions of functions
for acquiring device resources.

Acked-by: Daniel Thompson <[email protected]>
Reviewed-by: Noralf Trønnes <[email protected]>
Reviewed-by: Sean Paul <[email protected]>
Signed-off-by: Meghana Madhyastha <[email protected]>
Signed-off-by: Sean Paul <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/021f8fecfa3f374dc5dcb70fb07a6f6b019bea7b.1516810725.git.meghana.madhyastha@gmail.com

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video: backlight: Add of_find_backlight helper in backlight.c

Add of_find_backlight, a helper function which is a generic version
of tinydrm_of_find_backlight that can be used by other drivers to av

video: backlight: Add of_find_backlight helper in backlight.c

Add of_find_backlight, a helper function which is a generic version
of tinydrm_of_find_backlight that can be used by other drivers to avoid
repetition of code and simplify things.

Acked-by: Daniel Thompson <[email protected]>
Reviewed-by: Noralf Trønnes <[email protected]>
Reviewed-by: Sean Paul <[email protected]>
Reviewed-by: Thierry Reding <[email protected]>
Signed-off-by: Meghana Madhyastha <[email protected]>
Signed-off-by: Sean Paul <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/116d160ba78be2e6dcbdcb6855622bce67da9472.1516810725.git.meghana.madhyastha@gmail.com

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backlight: Report error on failure

It is possible to update the backlight power and the brightness using
the sysfs and on writing it either returns the count or if the callback
function does not exi

backlight: Report error on failure

It is possible to update the backlight power and the brightness using
the sysfs and on writing it either returns the count or if the callback
function does not exist then returns the error code 'ENXIO'.

We have a situation where the userspace client is writing to the sysfs
to update the power and since the callback function exists the client
receives the return value as count and considers the operation to be
successful. That is correct as the write to the sysfs was successful.
But there is no way to know if the actual operation was done or not.

backlight_update_status() returns the error code if it fails. Pass that
to the userspace client who is trying to update the power so that the
client knows that the operation failed.

Signed-off-by: Sudip Mukherjee <[email protected]>
Acked-by: Daniel Thompson <[email protected]>
Signed-off-by: Lee Jones <[email protected]>

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video / backlight: remove the backlight_device_registered API

Since we will need the backlight_device_get_by_type API, we can use it
instead of the backlight_device_registered API whenever necessary

video / backlight: remove the backlight_device_registered API

Since we will need the backlight_device_get_by_type API, we can use it
instead of the backlight_device_registered API whenever necessary so
remove the backlight_device_registered API.

Signed-off-by: Aaron Lu <[email protected]>
Acked-by: Jingoo Han <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>

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video / backlight: add two APIs for drivers to use

It is useful to get the backlight device's pointer and use it to set
backlight in some cases(the following patch will make use of it) so add
the tw

video / backlight: add two APIs for drivers to use

It is useful to get the backlight device's pointer and use it to set
backlight in some cases(the following patch will make use of it) so add
the two APIs and export them.

Signed-off-by: Aaron Lu <[email protected]>
Acked-by: Jingoo Han <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>

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