From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.9 required=3.0 tests=FROM_EXCESS_BASE64, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0D732C43441 for ; Fri, 16 Nov 2018 08:21:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 59B552145D for ; Fri, 16 Nov 2018 08:21:09 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 59B552145D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=KARO-electronics.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389300AbeKPScZ convert rfc822-to-8bit (ORCPT ); Fri, 16 Nov 2018 13:32:25 -0500 Received: from smtprelay05.ispgateway.de ([80.67.31.98]:63712 "EHLO smtprelay05.ispgateway.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727405AbeKPScY (ORCPT ); Fri, 16 Nov 2018 13:32:24 -0500 X-Greylist: delayed 2797 seconds by postgrey-1.27 at vger.kernel.org; Fri, 16 Nov 2018 13:32:23 EST Received: from [89.1.81.74] (helo=ipc1.ka-ro) by smtprelay05.ispgateway.de with esmtpsa (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.90_1) (envelope-from ) id 1gNYe7-00063P-UR; Fri, 16 Nov 2018 08:34:31 +0100 Date: Fri, 16 Nov 2018 08:34:30 +0100 From: Lothar =?UTF-8?B?V2HDn21hbm4=?= To: Uwe =?UTF-8?B?S2xlaW5lLUvDtm5pZw==?= Cc: Thierry Reding , =?UTF-8?B?Vm9rw6HEjQ==?= Michal , Mark Rutland , "devicetree@vger.kernel.org" , "linux-pwm@vger.kernel.org" , Lukasz Majewski , "linux-kernel@vger.kernel.org" , Rob Herring , "kernel@pengutronix.de" , Fabio Estevam , Linus Walleij Subject: Re: [RCF PATCH,v2,2/2] pwm: imx: Configure output to GPIO in disabled state Message-ID: <20181116083430.7f1d8452@ipc1.ka-ro> In-Reply-To: <20181115203733.qvonika6yhn2bsnb@pengutronix.de> References: <20181107093355.e4n3irrnkybqsjvc@pengutronix.de> <20181107150125.7cpd4v5t7yi2254c@pengutronix.de> <4fbb7307-df01-d7bd-f2e2-e05e6d17807d@ysoft.com> <20181108191855.zuon3ecv4yjfbs7g@pengutronix.de> <283cfef3-16d0-8bd4-e306-6e34d44c3a86@ysoft.com> <20181109165555.vqbiwh4hlcnozdna@pengutronix.de> <20181114113449.GB2620@ulmo> <20181114215120.vddykljqyavm64wj@pengutronix.de> <20181115152545.GA8611@ulmo> <20181115203733.qvonika6yhn2bsnb@pengutronix.de> Organization: Ka-Ro electronics GmbH MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT X-Df-Sender: bHdAa2Fyby1lbGVjdHJvbmljcy5kZQ== Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Uwe Kleine-König wrote: > Hello Thierry, > > On Thu, Nov 15, 2018 at 04:25:45PM +0100, Thierry Reding wrote: > > On Wed, Nov 14, 2018 at 10:51:20PM +0100, Uwe Kleine-König wrote: > > > On Wed, Nov 14, 2018 at 12:34:49PM +0100, Thierry Reding wrote: [...] > > > Also dts writes don't need to lookup the needed GPIO numbers and pinctrl. > > > > Just to clarify: I don't think that we need to get the GPIO number > > involved in this case, because we don't have to reconfigure the pin as > > GPIO to make this work. The only reason that Michal's proposal did that > > is because that was believed to be necessary. But if the pin can just be > > configured with a 100k pull-up, that's enough to pull the pin high when > > we need it. > > Unless the gpio happens to be configured as output at the wrong value. > Further I'm not sure if the pwm in disabled state actively pulls to 0 > and if in this state the PU of the pin is good enough to ensure a one > here. That would need verification first. > No. You can disable the output driver via pinctrl, so that only the selected pull-up/down is relevant. The pin function and GPIO register settings don't matter at all in this case. Lothar Waßmann -- ___________________________________________________________ Ka-Ro electronics GmbH | Pascalstraße 22 | D - 52076 Aachen Phone: +49 2408 1402-0 | Fax: +49 2408 1402-10 Geschäftsführer: Matthias Kaussen Handelsregistereintrag: Amtsgericht Aachen, HRB 4996 www.karo-electronics.de | info@karo-electronics.de ___________________________________________________________