From patchwork Sun Mar 8 20:57:32 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pavel Machek X-Patchwork-Id: 447820 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 2BB291401AA for ; Mon, 9 Mar 2015 07:57:52 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752916AbbCHU5h (ORCPT ); Sun, 8 Mar 2015 16:57:37 -0400 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:50862 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752649AbbCHU5g (ORCPT ); Sun, 8 Mar 2015 16:57:36 -0400 Received: by atrey.karlin.mff.cuni.cz (Postfix, from userid 512) id 5FE4A81F1E; Sun, 8 Mar 2015 21:57:33 +0100 (CET) Date: Sun, 8 Mar 2015 21:57:32 +0100 From: Pavel Machek To: Alexandre Courbot Cc: Geert Uytterhoeven , Felipe Balbi , Bryan Wu , Richard Purdie , "linux-leds@vger.kernel.org" , Linux Kernel Mailing List , Linux OMAP Mailing List , "linux-gpio@vger.kernel.org" Subject: RGB LED control (was Re: "advanced" LED controllers) Message-ID: <20150308205732.GA385@amd> References: <20150219211424.GN13603@saruman.tx.rr.com> <20150302092111.GA19233@amd> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-gpio-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org Ok, so I played with RGB LED a bit, and we have quite a gap in documentation: what 50% brightness means is non-trivial and very important in case we want to do smooth blinking and color transitions. Signed-off-by: Pavel Machek diff --git a/Documentation/ABI/testing/sysfs-class-led b/Documentation/ABI/testing/sysfs-class-led index 3646ec8..649d7a6 100644 --- a/Documentation/ABI/testing/sysfs-class-led +++ b/Documentation/ABI/testing/sysfs-class-led @@ -8,6 +8,11 @@ Description: non-zero brightness settings. The value is between 0 and /sys/class/leds//max_brightness. + If LED supports continuous brightness settings, 50% brightness + should correspond to 50% brightness perceived by human, in a similar + manner pixel brightness on monitor does (not 50% PWM). + + What: /sys/class/leds//max_brightness Date: March 2006 KernelVersion: 2.6.17