From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754089AbcDAVSt (ORCPT ); Fri, 1 Apr 2016 17:18:49 -0400 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:51773 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751093AbcDAVSr (ORCPT ); Fri, 1 Apr 2016 17:18:47 -0400 Date: Fri, 1 Apr 2016 23:18:44 +0200 From: Pavel Machek To: Jacek Anaszewski Cc: Jacek Anaszewski , Heiner Kallweit , Greg KH , linux-leds@vger.kernel.org, Benjamin Tissoires , linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org, pali.rohar@gmail.com, sre@kernel.org, khilman@kernel.org, aaro.koskinen@iki.fi, ivo.g.dimitrov.75@gmail.com, Patrik Bachan , serge@hallyn.com Subject: Re: [PATCH v5 1/4] leds: core: add generic support for RGB Color LED's Message-ID: <20160401211844.GA21768@amd> References: <20160401135748.GD11860@amd> <56FEC444.4040106@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <56FEC444.4040106@gmail.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi! > >>It would have the same downsides as in case of having r, g and b in > >>separate attributes, i.e. - problems with setting LED colour in > >>a consistent way. This way LED blinking in whatever colour couldn't > >>be supported reliably. It was one of your primary rationale standing > >>behind this design, if I remember correctly. Second - what about > >>triggers? We've had a long discussion about it and this design turned > >>out to be most fitting. > > > >Are on/off triggers really that useful for a LED that can produce 16 > >million colors? > > > >I believe we should support patterns for RGB LEDs. Something like > >[ (time, r, g, b), ... ] . Ok, what about this one? > > > >Lets say we have > > > >/sys/class/pattern/lp5533::0 > >/sys/class/pattern/software::0 > > > >/sys/class/led/n900::red ; default trigger "lp5533::0:0" > >/sys/class/led/n900::green ; default trigger "lp5533::0:1" > >/sys/class/led/n900::blue ; default trigger "lp5533::0:2" > > > >Normally, pattern would correspond to one RGB LED. We could have > >attribute "/sys/class/pattern/lp5533::0/color" containing R,G,B for > >this pattern. > > This involves the same issue you were opposed to: three values per > sysfs attribute. And solves a lot of other things. Like actually being backwards compatible. And yes, it involves three values in a file, but now it is array of led brightnesses, and that might actually be acceptable. (At least the values have uniform meaning). Plus, it is not "issue you were opposed to" it is "something that is not permitted by sysfs maintainers". Thanks, Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html