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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C987FC77B7A for ; Thu, 25 May 2023 14:24:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234743AbjEYOYi (ORCPT ); Thu, 25 May 2023 10:24:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54874 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233993AbjEYOYi (ORCPT ); Thu, 25 May 2023 10:24:38 -0400 Received: from mail.hugovil.com (mail.hugovil.com [162.243.120.170]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C6BAD187; Thu, 25 May 2023 07:24:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=hugovil.com ; s=x; h=Subject:Content-Transfer-Encoding:Content-Type:Mime-Version: References:In-Reply-To:Message-Id:Cc:To:From:Date:Sender:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=4EiB2AlR+/z+R1o2De2Qde2ZQ5SW+JoatwDRo240840=; b=vR44fhXQDG6zkr11gJByncTwgc EXPH+B7r/wny2rnUTeVD0cXBofM0ZIeXSjE8ljsYR5A+9k53BZsX+PzzgqTZJoax+5R0EsrX4pfBv YM1BteQXhJQQFCHxPdKg8+t+abRoy0T1Izlrk4cXyk251v09n75RRJegqA3IPUyi0lxw=; Received: from modemcable168.174-80-70.mc.videotron.ca ([70.80.174.168]:53208 helo=pettiford) by mail.hugovil.com with esmtpa (Exim 4.92) (envelope-from ) id 1q2BtE-0008F5-8X; Thu, 25 May 2023 10:24:28 -0400 Date: Thu, 25 May 2023 10:24:27 -0400 From: Hugo Villeneuve To: andy.shevchenko@gmail.com Cc: gregkh@linuxfoundation.org, robh+dt@kernel.org, krzysztof.kozlowski+dt@linaro.org, conor+dt@kernel.org, jirislaby@kernel.org, jringle@gridpoint.com, tomasz.mon@camlingroup.com, l.perczak@camlintechnologies.com, linux-serial@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-gpio@vger.kernel.org, Hugo Villeneuve Message-Id: <20230525102427.dfd362c6a0c68a2f8e99accf@hugovil.com> In-Reply-To: References: <20230525040324.3773741-1-hugo@hugovil.com> <20230525040324.3773741-7-hugo@hugovil.com> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-SA-Exim-Connect-IP: 70.80.174.168 X-SA-Exim-Mail-From: hugo@hugovil.com Subject: Re: [PATCH v3 06/11] serial: sc16is7xx: fix bug when first setting GPIO direction X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on mail.hugovil.com) Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On Thu, 25 May 2023 14:10:27 +0300 andy.shevchenko@gmail.com wrote: > Thu, May 25, 2023 at 12:03:20AM -0400, Hugo Villeneuve kirjoitti: > > From: Hugo Villeneuve > > > > When we want to configure a pin as an output pin with a value of logic > > 0, we end up as having a value of logic 1 on the output pin. Setting a > > logic 0 a second time (or more) after that will correctly output a > > logic 0 on the output pin. > > > > By default, all GPIO pins are configured as inputs. When we enter > > c16is7xx_gpio_direction_output() for the first time, we first set the > > Missing 's'. Fixed. > > desired value in IOSTATE, and then we configure the pin as an output. > > The datasheet states that writing to IOSTATE register will trigger a > > transfer of the value to the I/O pin configured as output, so if the > > pin is configured as an input, nothing will be transferred. > > > > Therefore, set the direction first in IODIR, and then set the desired > > value in IOSTATE. > > > > This is what is done in NXP application note AN10587. > > -- > With Best Regards, > Andy Shevchenko > > >