video/backlight: document sysfs interface

Date and KernelVersion may be wrong because the backlight
interface was introduced before git initial import.

Cc:Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Corentin Chary <corentincj@iksaif.net>
Signed-off-by: Len Brown <len.brown@intel.com>
This commit is contained in:
Corentin Chary 2009-08-28 12:56:43 +00:00 committed by Len Brown
parent d0a6825c92
commit 3c4c1b69a2

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What: /sys/class/backlight/<backlight>/bl_power
Date: April 2005
KernelVersion: 2.6.12
Contact: Richard Purdie <rpurdie@rpsys.net>
Description:
Control BACKLIGHT power, values are FB_BLANK_* from fb.h
- FB_BLANK_UNBLANK (0) : power on.
- FB_BLANK_POWERDOWN (4) : power off
Users: HAL
What: /sys/class/backlight/<backlight>/brightness
Date: April 2005
KernelVersion: 2.6.12
Contact: Richard Purdie <rpurdie@rpsys.net>
Description:
Control the brightness for this <backlight>. Values
are between 0 and max_brightness. This file will also
show the brightness level stored in the driver, which
may not be the actual brightness (see actual_brightness).
Users: HAL
What: /sys/class/backlight/<backlight>/actual_brightness
Date: March 2006
KernelVersion: 2.6.17
Contact: Richard Purdie <rpurdie@rpsys.net>
Description:
Show the actual brightness by querying the hardware.
Users: HAL
What: /sys/class/backlight/<backlight>/max_brightness
Date: April 2005
KernelVersion: 2.6.12
Contact: Richard Purdie <rpurdie@rpsys.net>
Description:
Maximum brightness for <backlight>.
Users: HAL