From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S937500AbeBUQqe (ORCPT ); Wed, 21 Feb 2018 11:46:34 -0500 Received: from avon.wwwdotorg.org ([104.237.132.123]:38712 "EHLO avon.wwwdotorg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933280AbeBUQqb (ORCPT ); Wed, 21 Feb 2018 11:46:31 -0500 Subject: Re: [PATCH] ARM: dtc: tegra: enable front panel leds in TrimSlice To: Tomasz Maciej Nowak Cc: thierry.reding@gmail.com, jonathanh@nvidia.com, linux-tegra@vger.kernel.org, robh+dt@kernel.org, mark.rutland@arm.com, linux@armlinux.org.uk, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: <20180219201623.6987-1-tmn505@gmail.com> <57945bd2-d8c2-f7bc-f01f-29d679762446@wwwdotorg.org> <873b01dc-3ca5-3151-2654-a8272cb9dd88@gmail.com> From: Stephen Warren Message-ID: Date: Wed, 21 Feb 2018 09:46:28 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: <873b01dc-3ca5-3151-2654-a8272cb9dd88@gmail.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/21/2018 09:20 AM, Tomasz Maciej Nowak wrote: > W dniu 20.02.2018 o 20:55, Stephen Warren pisze: >> On 02/19/2018 01:16 PM, Tomasz Maciej Nowak wrote: >>> Adds device nodes for two front panel LEDs. >> >> Why do you need to change the pinmux settings? Configuring a pin as a >> GPIO should override any pinmux special function selection and hence >> make it irrelevant, so I don't think you should need to change the >> pinmux. > > At first I did exactly that without changing the pinmux, but the LEDs > didn't light up. After that I compared with CompuLab source tree [1]. > The pinmux was specified as in my patch. With this change the LEDs are > fully functional. > > 1. > https://gitorious.org/trimslice-kernel/trimslice-kernel?p=trimslice-kernel:trimslice-kernel.git;a=blob;f=arch/arm/mach-tegra/board-trimslice-pinmux.c;h=cc6d5225d97eb9327c820bf1d5b2bc16ab8c6dda;hb=d25bf45d6314089489b30d218ed8a0d6d94417f9#l45 Oh I see. Your patch isn't changing the pinmux function selection but the other configuration bits, which are relevant even when the pin is in GPIO mode. In particular, it clears the tristate bit for the dte pingroup. That makes perfect sense.