From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757528AbcIPF7i (ORCPT ); Fri, 16 Sep 2016 01:59:38 -0400 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:55580 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751081AbcIPF7a (ORCPT ); Fri, 16 Sep 2016 01:59:30 -0400 Date: Fri, 16 Sep 2016 07:59:27 +0200 From: Pavel Machek To: David Lechner Cc: Jacek Anaszewski , Richard Purdie , linux-kernel@vger.kernel.org, linux-leds@vger.kernel.org, Marcel Holtmann Subject: Re: [PATCH v3] leds: Introduce userspace leds driver Message-ID: <20160916055927.GC13205@amd> References: <1473439776-15655-1-git-send-email-david@lechnology.com> <80597ded-f4b4-2990-3eae-e72276296d1a@samsung.com> <20160915130831.GJ13132@amd> <313cbae5-fd66-f0ae-79a9-a3f4273d6f9c@samsung.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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! +The current brightness is found by reading a single byte from the character +device. Values are unsigned: 0 to 255. Reading does not block and always returns +the most recent brightness value. The device node can also be polled to notify +when the brightness value changes. What is going on there? We have O_NONBLOCK, user should be able to select if he wants blocking behaviour or not. And yes, there's interface for creating a LED, but not one for deleting it? And... how is it going to work with multiple LEDs? Userspace gets single bytes with brightness. How does it know to which LED the brightness belongs? Thanks, Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html