Documentation/ABI/testing/sysfs-class-backlight

Source file repositories/reference/linux-study-clean/Documentation/ABI/testing/sysfs-class-backlight

File Facts

System
Linux kernel
Corpus path
Documentation/ABI/testing/sysfs-class-backlight
Extension
[no extension]
Size
6483 bytes
Lines
187
Domain
Support Tooling And Documentation
Bucket
Documentation
Inferred role
Support Tooling And Documentation: Documentation
Status
atlas-only

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Dependency Surface

Detected Declarations

Annotated Snippet

What:		/sys/class/backlight/<backlight>/scale
Date:		July 2019
KernelVersion:	5.4
Contact:	Daniel Thompson <daniel.thompson@linaro.org>
Description:
		Description of the scale of the brightness curve.

		The human eye senses brightness approximately logarithmically,
		hence linear changes in brightness are perceived as being
		non-linear. To achieve a linear perception of brightness changes
		controls like sliders need to apply a logarithmic mapping for
		backlights with a linear brightness curve.

		Possible values of the attribute are:

		unknown
		  The scale of the brightness curve is unknown.

		linear
		  The brightness changes linearly with each step. Brightness
		  controls should apply a logarithmic mapping for a linear
		  perception.

		non-linear
		  The brightness changes non-linearly with each step. Brightness
		  controls should use a linear mapping for a linear perception.

What:		/sys/class/backlight/<backlight>/ambient_light_level
Date:		Apr, 2010
KernelVersion:	v2.6.35
Contact:	Michael Hennerich <michael.hennerich@analog.com>
Description:
		(RO) Get conversion value of the light sensor.

		The value is automatically updated every 80 ms when the
		light sensor is enabled.

		The value range is device-driver specific:

		For ADP8870:

		  It returns integer between 0 (dark) and 8000 (max ambient
		  brightness).

		For ADP8860:

		  It returns a 13-bits integer.

What:		/sys/class/backlight/<backlight>/ambient_light_zone
Date:		Apr, 2010
KernelVersion:	v2.6.35
Contact:	Michael Hennerich <michael.hennerich@analog.com>,
		device-drivers-devel@blackfin.uclinux.org

Description:
		(RW) Read or write the specific brightness level at which the
		backlight operates.

		The value meaning is device-driver specific:

		For ADP8860:

		  ==	==========================
		   0	Off: Backlight set to 0 mA
		   1	Level 1: daylight
		   2	Level 2: bright
		   3	Level 3: dark
		  ==	==========================

		For ADP8870:

Annotation

Implementation Notes