Re: [PATCH v6 1/4] leds: class: Add new optional brightness_hw_changed attribute

["Pali Rohár" <pali.rohar@gmail.com>]

On Wednesday 25 January 2017 17:11:27 Hans de Goede wrote:
> Some LEDs may have their brightness level changed autonomously
> (outside of kernel control) by hardware / firmware. This commit
> adds support for an optional brightness_hw_changed attribute to
> signal such changes to userspace (if a driver can detect them):
> 
> What:		/sys/class/leds/<led>/brightness_hw_changed
> Date:		January 2017
> KernelVersion:	4.11
> Description:
> 		Last hardware set brightness level for this LED. Some LEDs
> 		may be changed autonomously by hardware/firmware. Only LEDs
> 		where this happens and the driver can detect this, will
> 		have this file.
> 
> 		This file supports poll() to detect when the hardware
> 		changes the brightness.
> 
> 		Reading this file will return the last brightness level set
> 		by the hardware, this may be different from the current
> 		brightness.
> 
> Drivers which want to support this, simply add LED_BRIGHT_HW_CHANGED to
> their flags field and call led_classdev_notify_brightness_hw_changed()
> with the hardware set brightness when they detect a hardware / firmware
> triggered brightness change.
> 
> Signed-off-by: Hans de Goede <hdegoede@redhat.com>

Just speculation: What about using name 'actual_brightness'? It provides
same output on read as actual_brightness from /sys/class/backlight/.

-- 
Pali Rohár
pali.rohar@gmail.com