Hi,

On 06/05/2017 11:16 PM, Pavel Machek wrote:

Hi!

quoted

Generally I came to a conclusion that it will be best to register
additional LED RGB class device in an addition to three LED class
devices representing each color. In order to avoid hard to solve
locking problems I propose to allow for simultaneous access to LED
class devices and LED RGB class device gathering them.

All in all, currently we also don't give an exclusive access to
a particular LED class device, which always can lead to overwriting
current brightness by another process. These issues must be arbitrated
by user space.

I propose that LED RGB class device exposed following files:

- red_brightness
- green_brightness
- blue_brightness
- latch_color

Actually, I'd just do single file, "rgb_brightness" with 3
values. Overhead of writing 3 values is pretty much 0.

You've always been strongly in favor of one-value-per-file
sysfs rule of thumb, but I'm OK with this approach as well :-)

-- 
Best regards,
Jacek Anaszewski