Re: [PATCH V2 1/2] leds: leds-qti-rgb: Add LED driver for QTI TRI_LED module

From	Pavel Machek <pavel@ucw.cz>
Newsgroups	linux.kernel
Subject	Re: [PATCH V2 1/2] leds: leds-qti-rgb: Add LED driver for QTI TRI_LED module
Date	2017-06-06 22:20 +0200
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Hi!

> >> 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 :-)

Being values of same type (etc), this is actually permitted. And it is
better than hack with latch_color :-).

Good.
								Pavel

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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[PATCH V2 1/2] leds: leds-qti-rgb: Add LED driver for QTI TRI_LED module fenglinw@codeaurora.org - 2017-06-01 09:30 +0200
  Re: [PATCH V2 1/2] leds: leds-qti-rgb: Add LED driver for QTI TRI_LED  module Jacek Anaszewski <jacek.anaszewski@gmail.com> - 2017-06-04 20:40 +0200
    Re: [PATCH V2 1/2] leds: leds-qti-rgb: Add LED driver for QTI  TRI_LED module Pavel Machek <pavel@ucw.cz> - 2017-06-05 23:20 +0200
      Re: [PATCH V2 1/2] leds: leds-qti-rgb: Add LED driver for QTI TRI_LED  module Jacek Anaszewski <jacek.anaszewski@gmail.com> - 2017-06-06 22:10 +0200
        Re: [PATCH V2 1/2] leds: leds-qti-rgb: Add LED driver for QTI  TRI_LED module Pavel Machek <pavel@ucw.cz> - 2017-06-06 22:20 +0200

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