In all cases in which a struct acpi_driver is used for binding a driver
to an ACPI device object, a corresponding platform device is created by
the ACPI core and that device is regarded as a proper representation of
underlying hardware. Accordingly, a struct platform_driver should be
used by driver code to bind to that device. There are multiple reasons
why drivers should not bind directly to ACPI device objects [1].
Overall, it is better to bind drivers to platform devices than to their
ACPI companions, so convert the Apple Backlight ACPI driver to a
platform one.
While this is not expected to alter functionality, it changes sysfs
layout and so it will be visible to user space.
Link: https://lore.kernel.org/all/2396510.ElGaqSPkdT@rafael.j.wysocki/ [1]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Daniel Thompson (RISCstar) <danielt@kernel.org>
Link: https://patch.msgid.link/5084777.GXAFRqVoOG@rafael.j.wysocki
Signed-off-by: Lee Jones <lee@kernel.org>
The devm_gpiod_get_optional() function may return an ERR_PTR in case of
genuine GPIO acquisition errors, not just NULL which indicates the
legitimate absence of an optional GPIO.
Add an IS_ERR() check after the call in sky81452_bl_parse_dt(). On
error, return the error code to ensure proper failure handling rather
than proceeding with invalid pointers.
Fixes: e1915eec54 ("backlight: sky81452: Convert to GPIO descriptors")
Signed-off-by: Chen Ni <nichen@iscas.ac.cn>
Reviewed-by: Linus Walleij <linusw@kernel.org>
Reviewed-by: Daniel Thompson (RISCstar) <danielt@kernel.org>
Link: https://patch.msgid.link/20260203021625.578678-1-nichen@iscas.ac.cn
Signed-off-by: Lee Jones <lee@kernel.org>
This was done entirely with mindless brute force, using
git grep -l '\<k[vmz]*alloc_objs*(.*, GFP_KERNEL)' |
xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/'
to convert the new alloc_obj() users that had a simple GFP_KERNEL
argument to just drop that argument.
Note that due to the extreme simplicity of the scripting, any slightly
more complex cases spread over multiple lines would not be triggered:
they definitely exist, but this covers the vast bulk of the cases, and
the resulting diff is also then easier to check automatically.
For the same reason the 'flex' versions will be done as a separate
conversion.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is the result of running the Coccinelle script from
scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to
avoid scalar types (which need careful case-by-case checking), and
instead replace kmalloc-family calls that allocate struct or union
object instances:
Single allocations: kmalloc(sizeof(TYPE), ...)
are replaced with: kmalloc_obj(TYPE, ...)
Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...)
are replaced with: kmalloc_objs(TYPE, COUNT, ...)
Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...)
are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...)
(where TYPE may also be *VAR)
The resulting allocations no longer return "void *", instead returning
"TYPE *".
Signed-off-by: Kees Cook <kees@kernel.org>
WLED4 found in PMI8994 supports different ovp values.
Fixes: 6fc632d3e3 ("video: backlight: qcom-wled: Add PMI8994 compatible")
Signed-off-by: Barnabás Czémán <barnabas.czeman@mainlining.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Reviewed-by: Daniel Thompson (RISCstar) <danielt@kernel.org>
Link: https://patch.msgid.link/20260116-pmi8950-wled-v3-2-e6c93de84079@mainlining.org
Signed-off-by: Lee Jones <lee@kernel.org>
The driver uses GPIO descriptor API (devm_gpiod_get,
gpiod_set_value_cansleep, GPIOD_OUT_LOW) but includes the legacy
<linux/gpio.h> header instead of <linux/gpio/consumer.h>.
When CONFIG_GPIOLIB is not set, <linux/gpio.h> does not include
<linux/gpio/consumer.h>, causing build errors:
error: implicit declaration of function 'gpiod_set_value_cansleep'
error: implicit declaration of function 'devm_gpiod_get'
error: 'GPIOD_OUT_LOW' undeclared
Fix by including the correct header <linux/gpio/consumer.h>.
Fixes: 147b38a5ad ("backlight: aw99706: Add support for Awinic AW99706 backlight")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202512171631.uKXlYwqu-lkp@intel.com/
Signed-off-by: Junjie Cao <junjie.cao@intel.com>
Reviewed-by: Daniel Thompson (RISCstar) <danielt@kernel.org>
Link: https://patch.msgid.link/20260111130117.5041-1-junjie.cao@intel.com
Signed-off-by: Lee Jones <lee@kernel.org>
This driver provides backlight brightness control through the Linux
backlight subsystem. It communicates with the board controller to
adjust LCD backlight using PWM signals. Communication is done
through Congatec Board Controller core driver.
Tested-by: Thomas Richard <thomas.richard@bootlin.com>
Reviewed-by: Thomas Richard <thomas.richard@bootlin.com>
Reviewed-by: Daniel Thompson (RISCstar) <danielt@kernel.org>
Signed-off-by: Petri Karhula <petri.karhula@novatron.fi>
Link: https://patch.msgid.link/20251205-cgbc-backlight-v6-1-e4175b0bf406@novatron.fi
Signed-off-by: Lee Jones <lee@kernel.org>
When building for a platform without CONFIG_PM_SLEEP, such as s390,
there are two unused function warnings:
drivers/video/backlight/aw99706.c:436:12: error: 'aw99706_resume' defined but not used [-Werror=unused-function]
436 | static int aw99706_resume(struct device *dev)
| ^~~~~~~~~~~~~~
drivers/video/backlight/aw99706.c:429:12: error: 'aw99706_suspend' defined but not used [-Werror=unused-function]
429 | static int aw99706_suspend(struct device *dev)
| ^~~~~~~~~~~~~~~
SET_SYSTEM_SLEEP_PM_OPS, used within SIMPLE_DEV_PM_OPS, expands to
nothing when CONFIG_PM_SLEEP is not set, so these functions are
completely unused in this configuration.
SIMPLE_DEV_PM_OPS is deprecated in favor of DEFINE_SIMPLE_DEV_PM_OPS,
which avoids this issue by using pm_sleep_ptr to make these callbacks
NULL when CONFIG_PM_SLEEP is unset while making the callback functions
always appear used to the compiler regardless of configuration. Switch
to DEFINE_SIMPLE_DEV_PM_OPS for aw99706_pm_ops to clear up the warning.
Additionally, wrap the pointer to aw99706_pm_ops in pm_ptr() in
aw99706_i2c_driver to ensure that the structure is completely eliminated
in configurations without CONFIG_PM.
Fixes: 88a8e9b49ee8 ("backlight: aw99706: Add support for Awinic AW99706 backlight")
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Link: https://patch.msgid.link/20251120-backlight-aw99706-fix-unused-pm-functions-v1-1-8b9c17c4e783@kernel.org
Signed-off-by: Lee Jones <lee@kernel.org>
Add support for Awinic AW99706 backlight, which can be found in
tablet and notebook backlight, one case is the Lenovo Legion Y700
Gen4. This driver refers to the official datasheets and android
driver, they can be found in [1].
[1] https://www.awinic.com/en/productDetail/AW99706QNR
Signed-off-by: Junjie Cao <caojunjie650@gmail.com>
Tested-by: Pengyu Luo <mitltlatltl@gmail.com>
Signed-off-by: Pengyu Luo <mitltlatltl@gmail.com>
Reviewed-by: Daniel Thompson (RISCstar) <danielt@kernel.org>
Link: https://patch.msgid.link/20251109032240.3422503-3-caojunjie650@gmail.com
Signed-off-by: Lee Jones <lee@kernel.org>
LED Backlight is a consumer of one or multiple LED class devices, but
devlink is currently unable to create correct supplier-producer links when
the supplier is a class device. It creates instead a link where the
supplier is the parent of the expected device.
One consequence is that removal order is not correctly enforced.
Issues happen for example with the following sections in a device tree
overlay:
// An LED driver chip
pca9632@62 {
compatible = "nxp,pca9632";
reg = <0x62>;
// ...
addon_led_pwm: led-pwm@3 {
reg = <3>;
label = "addon:led:pwm";
};
};
backlight-addon {
compatible = "led-backlight";
leds = <&addon_led_pwm>;
brightness-levels = <255>;
default-brightness-level = <255>;
};
In this example, the devlink should be created between the backlight-addon
(consumer) and the pca9632@62 (supplier). Instead it is created between the
backlight-addon (consumer) and the parent of the pca9632@62, which is
typically the I2C bus adapter.
On removal of the above overlay, the LED driver can be removed before the
backlight device, resulting in:
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000010
...
Call trace:
led_put+0xe0/0x140
devm_led_release+0x6c/0x98
Another way to reproduce the bug without any device tree overlays is
unbinding the LED class device (pca9632@62) before unbinding the consumer
(backlight-addon):
echo 11-0062 >/sys/bus/i2c/drivers/leds-pca963x/unbind
echo ...backlight-dock >/sys/bus/platform/drivers/led-backlight/unbind
Fix by adding a devlink between the consuming led-backlight device and the
supplying LED device, as other drivers and subsystems do as well.
Fixes: ae232e45ac ("backlight: add led-backlight driver")
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Reviewed-by: Daniel Thompson (RISCstar) <danielt@kernel.org>
Reviewed-by: Herve Codina <herve.codina@bootlin.com>
Tested-by: Alexander Sverdlin <alexander.sverdlin@siemens.com>
Link: https://patch.msgid.link/20250519-led-backlight-add-devlink-to-supplier-class-device-v6-1-845224aeb2ce@bootlin.com
Signed-off-by: Lee Jones <lee@kernel.org>
Include <linux/mod_devicetable.h> to declare struct of_device_id.
Avoids dependency on backlight header to include it.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: "Daniel Thompson (RISCstar)" <danielt@kernel.org>
Link: https://lore.kernel.org/r/20250715122643.137027-15-tzimmermann@suse.de
Signed-off-by: Lee Jones <lee@kernel.org>
Include <linux/of.h> to declare struct device_node and include
<linux/mod_devicetable.h> to declare struct of_device_id. Avoids
dependency on backlight header to include it.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: "Daniel Thompson (RISCstar)" <danielt@kernel.org>
Link: https://lore.kernel.org/r/20250715122643.137027-14-tzimmermann@suse.de
Signed-off-by: Lee Jones <lee@kernel.org>
Include <linux/of.h> to declare struct of_count_phandle_with_args().
Avoids dependency on backlight header to include it.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: "Daniel Thompson (RISCstar)" <danielt@kernel.org>
Link: https://lore.kernel.org/r/20250715122643.137027-13-tzimmermann@suse.de
Signed-off-by: Lee Jones <lee@kernel.org>
Include <linux/mod_devicetable.h> to declare struct of_device_id.
Avoids dependency on backlight header to include it.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Nick Chan <towinchenmi@gmail.com>
Reviewed-by: "Daniel Thompson (RISCstar)" <danielt@kernel.org>
Acked-by: Duje Mihanović <duje.mihanovic@skole.hr>
Link: https://lore.kernel.org/r/20250715122643.137027-12-tzimmermann@suse.de
Signed-off-by: Lee Jones <lee@kernel.org>
Include <linux/io.h> to declare IOMEM(). Avoids dependency on
backlight header to include it.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: "Daniel Thompson (RISCstar)" <danielt@kernel.org>
Link: https://lore.kernel.org/r/20250715122643.137027-11-tzimmermann@suse.de
Signed-off-by: Lee Jones <lee@kernel.org>
Include <linux/mod_devicetable.h> to declare struct platform_device_id.
Avoids dependency on backlight header to include it.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: "Daniel Thompson (RISCstar)" <danielt@kernel.org>
Link: https://lore.kernel.org/r/20250715122643.137027-10-tzimmermann@suse.de
Signed-off-by: Lee Jones <lee@kernel.org>
Include <linux/of.h> to declare various OF helpers. Avoids dependency
on backlight header to include it.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: "Daniel Thompson (RISCstar)" <danielt@kernel.org>
Link: https://lore.kernel.org/r/20250715122643.137027-9-tzimmermann@suse.de
Signed-off-by: Lee Jones <lee@kernel.org>
Include <linux/mod_devicetable.h> to declare struct of_device_id.
Avoids dependency on backlight header to include it.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Nick Chan <towinchenmi@gmail.com>
Reviewed-by: "Daniel Thompson (RISCstar)" <danielt@kernel.org>
Link: https://lore.kernel.org/r/20250715122643.137027-8-tzimmermann@suse.de
Signed-off-by: Lee Jones <lee@kernel.org>
Include <linux/of.h> to avoid dependency on backlight header to
include it.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: "Daniel Thompson (RISCstar)" <danielt@kernel.org>
Link: https://lore.kernel.org/r/20250715122643.137027-7-tzimmermann@suse.de
Signed-off-by: Lee Jones <lee@kernel.org>
According to LP8556 datasheet EPROM region starts at 0x98 so adjust value
in the driver accordingly.
Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com>
Reviewed-by: "Daniel Thompson (RISCstar)" <danielt@kernel.org>
Link: https://lore.kernel.org/r/20250909074304.92135-2-clamor95@gmail.com
Signed-off-by: Lee Jones <lee@kernel.org>
Replace calls of devm_kzalloc() with devm_kcalloc() in led_bl_get_leds()
and led_bl_parse_levels() for safer memory allocation with built-in
overflow protection.
Signed-off-by: Qianfeng Rong <rongqianfeng@vivo.com>
Reviewed-by: "Daniel Thompson (RISCstar)" <danielt@kernel.org>
Link: https://lore.kernel.org/r/20250819035804.433615-1-rongqianfeng@vivo.com
Signed-off-by: Lee Jones <lee@kernel.org>
Assigning values to a struct using a compound literal (since C99) also
guarantees that all unspecified struct members are empty-initialized, so
it properly replaces the memset to zero.
The code looks a bit nicer and more idiomatic (though that might be
subjective?). The resulting binary is a bit smaller. On ARCH=arm with
an allnoconfig + minimal changes to enable the mp3309c driver the
difference is 12 bytes.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Tested-by: Flavio Suligoi <f.suligoi@asem.it>
Reviewed-by: Daniel Thompson (RISCstar) <danielt@kernel.org>
Link: https://lore.kernel.org/r/14514a1b0d3df6438aa10bb74f1c4fc2367d9987.1751361465.git.u.kleine-koenig@baylibre.com
Signed-off-by: Lee Jones <lee@kernel.org>
pwm_apply_args() sole purpose is to initialize all parameters specified
in the device tree for consumers that rely on pwm_config() and
pwm_enable(). The mp3309c backlight driver uses pwm_apply_might_sleep()
which gets passed the full configuration and so doesn't rely on the
default being explicitly applied.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Tested-by: Flavio Suligoi <f.suligoi@asem.it>
Reviewed-by: Daniel Thompson (RISCstar) <danielt@kernel.org>
Link: https://lore.kernel.org/r/2d1075f5dd45c7c135e4326e279468de699f9d17.1751361465.git.u.kleine-koenig@baylibre.com
Signed-off-by: Lee Jones <lee@kernel.org>
devm_kasprintf() returns NULL when memory allocation fails. Currently,
wled_configure() does not check for this case, which results in a NULL
pointer dereference.
Add NULL check after devm_kasprintf() to prevent this issue.
Fixes: f86b77583d ("backlight: pm8941: Convert to using %pOFn instead of device_node.name")
Signed-off-by: Henry Martin <bsdhenrymartin@gmail.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Reviewed-by: "Daniel Thompson (RISCstar)" <danielt@kernel.org>
Link: https://lore.kernel.org/r/20250401091647.22784-1-bsdhenrymartin@gmail.com
Signed-off-by: Lee Jones <lee@kernel.org>
Remove support for fb events from the lcd subsystem. Provide the
helper lcd_notify_blank_all() instead. In fbdev, call
lcd_notify_blank_all() to inform the lcd subsystem of changes
to a display's blank state.
Fbdev maintains a list of all installed notifiers. Instead of fbdev
notifiers, maintain an internal list of lcd devices.
v3:
- export lcd_notify_mode_change_all() (kernel test robot)
v2:
- maintain global list of lcd devices
- avoid IS_REACHABLE() in source file
- use lock guards
- initialize lcd list and list mutex
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Simona Vetter <simona.vetter@ffwll.ch>
Reviewed-by: "Daniel Thompson (RISCstar)" <danielt@kernel.org>
Link: https://lore.kernel.org/r/20250321095517.313713-9-tzimmermann@suse.de
Signed-off-by: Lee Jones <lee@kernel.org>
Move the handling of display updates to separate helper functions.
There is code for handling fbdev blank events and fbdev mode changes.
The code currently runs from fbdev event notifiers, which will be
replaced.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: "Daniel Thompson (RISCstar)" <danielt@kernel.org>
Acked-by: Simona Vetter <simona.vetter@ffwll.ch>
Link: https://lore.kernel.org/r/20250321095517.313713-8-tzimmermann@suse.de
Signed-off-by: Lee Jones <lee@kernel.org>
Remove support for fb events from backlight subsystem. Provide the
helper backlight_notify_blank_all() instead. Also export the existing
helper backlight_notify_blank() to update a single backlight device.
In fbdev, call either helper to inform the backlight subsystem of
changes to a display's blank state. If the framebuffer device has a
specific backlight, only update this one; otherwise update all.
v4:
- protect blacklight declarations with IS_REACHABLE() (kernel test robot)
v3:
- declare empty fb_bl_notify_blank() as static inline (kernel test robot)
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Simona Vetter <simona.vetter@ffwll.ch>
Reviewed-by: "Daniel Thompson (RISCstar)" <danielt@kernel.org>
Link: https://lore.kernel.org/r/20250321095517.313713-7-tzimmermann@suse.de
Signed-off-by: Lee Jones <lee@kernel.org>
Move the handling of blank-state updates into a separate helper,
so that is can be called without the fbdev event. No functional
changes.
As a minor improvement over the original code, the update replaces
manual locking with a guard.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: "Daniel Thompson (RISCstar)" <danielt@kernel.org>
Acked-by: Simona Vetter <simona.vetter@ffwll.ch>
Link: https://lore.kernel.org/r/20250321095517.313713-6-tzimmermann@suse.de
Signed-off-by: Lee Jones <lee@kernel.org>
Look at the blank state provided by FB_EVENT_BLANK to determine
whether to enable or disable a backlight. Remove the tracking fields
from struct backlight_device.
Tracking requires three variables, fb_on, prev_fb_on and the
backlight's use_count. If fb_on is true, the display has been
unblanked. The backlight needs to be enabled if the display was
blanked before (i.e., prev_fb_on is false) or if use_count is still
at 0. If fb_on is false, the display has been blanked. In this case,
the backlight has to be disabled was unblanked before and the
backlight's use_count is greater than 0.
This change removes fbdev state tracking from blacklight. All the
backlight requires it its own use counter and information about
changes to the display. Removing fbdev internals makes backlight
drivers easier to integrate into other display drivers, such as DRM.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: "Daniel Thompson (RISCstar)" <danielt@kernel.org>
Acked-by: Simona Vetter <simona.vetter@ffwll.ch>
Link: https://lore.kernel.org/r/20250321095517.313713-5-tzimmermann@suse.de
Signed-off-by: Lee Jones <lee@kernel.org>
Add driver for backlight controllers attached via Apple DWI 2-wire
interface, which is found on some Apple iPhones, iPads and iPod touches
with a LCD display.
Although there is an existing apple_bl driver, it is for backlight
controllers on Intel Macs attached via PCI, which is completely different
from the Samsung-derived DWI block.
Reviewed-by: "Daniel Thompson (RISCstar)" <danielt@kernel.org>
Signed-off-by: Nick Chan <towinchenmi@gmail.com>
Reviewed-by: Neal Gompa <neal@gompa.dev>
Link: https://lore.kernel.org/r/20250214040306.16312-3-towinchenmi@gmail.com
Signed-off-by: Lee Jones <lee@kernel.org>
Lockdep detects the following issue on led-backlight removal:
[ 142.315935] ------------[ cut here ]------------
[ 142.315954] WARNING: CPU: 2 PID: 292 at drivers/leds/led-core.c:455 led_sysfs_enable+0x54/0x80
...
[ 142.500725] Call trace:
[ 142.503176] led_sysfs_enable+0x54/0x80 (P)
[ 142.507370] led_bl_remove+0x80/0xa8 [led_bl]
[ 142.511742] platform_remove+0x30/0x58
[ 142.515501] device_remove+0x54/0x90
...
Indeed, led_sysfs_enable() has to be called with the led_access
lock held.
Hold the lock when calling led_sysfs_disable().
Fixes: ae232e45ac ("backlight: add led-backlight driver")
Cc: stable@vger.kernel.org
Signed-off-by: Herve Codina <herve.codina@bootlin.com>
Link: https://lore.kernel.org/r/20250122091914.309533-1-herve.codina@bootlin.com
Signed-off-by: Lee Jones <lee@kernel.org>
