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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,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 7738BC282DE for ; Wed, 5 Jun 2019 09:35:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5A9F520717 for ; Wed, 5 Jun 2019 09:35:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727045AbfFEJfJ (ORCPT ); Wed, 5 Jun 2019 05:35:09 -0400 Received: from mx2.mailbox.org ([80.241.60.215]:59686 "EHLO mx2.mailbox.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726690AbfFEJfJ (ORCPT ); Wed, 5 Jun 2019 05:35:09 -0400 Received: from smtp2.mailbox.org (smtp2.mailbox.org [IPv6:2001:67c:2050:105:465:1:2:0]) (using TLSv1.2 with cipher ECDHE-RSA-CHACHA20-POLY1305 (256/256 bits)) (No client certificate requested) by mx2.mailbox.org (Postfix) with ESMTPS id 7734AA0191; Wed, 5 Jun 2019 11:35:06 +0200 (CEST) X-Virus-Scanned: amavisd-new at heinlein-support.de Received: from smtp2.mailbox.org ([80.241.60.241]) by spamfilter05.heinlein-hosting.de (spamfilter05.heinlein-hosting.de [80.241.56.123]) (amavisd-new, port 10030) with ESMTP id zXe4_JImFazw; Wed, 5 Jun 2019 11:35:02 +0200 (CEST) Subject: Re: [PATCH 2/2 v4] tty/serial/8250: use mctrl_gpio helpers To: Andy Shevchenko Cc: linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, Yegor Yefremov , Mika Westerberg , Giulio Benetti , Greg Kroah-Hartman , Johan Hovold References: <20190603083332.12480-1-sr@denx.de> <20190603083332.12480-2-sr@denx.de> <20190604165224.GP9224@smile.fi.intel.com> From: Stefan Roese Message-ID: <115804ab-7d7c-a656-e6f4-ad61b3e02705@denx.de> Date: Wed, 5 Jun 2019 11:35:01 +0200 MIME-Version: 1.0 In-Reply-To: <20190604165224.GP9224@smile.fi.intel.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04.06.19 18:52, Andy Shevchenko wrote: > On Mon, Jun 03, 2019 at 10:33:32AM +0200, Stefan Roese wrote: >> From: Yegor Yefremov >> >> This patch permits the usage for GPIOs to control >> the CTS/RTS/DTR/DSR/DCD/RI signals. > >> + if (up->gpios) { > >> + mctrl_gpio_set(up->gpios, mctrl_gpio); >> + } > > ... > >> + if (up->gpios) { > >> + mctrl_gpio = mctrl_gpio_get_outputs(up->gpios, &mctrl_gpio); > >> + } > > ... > >> + gpios = mctrl_gpio_init(&uart->port, 0); >> + if (IS_ERR(gpios)) { >> + if (PTR_ERR(gpios) != -ENOSYS) >> + return PTR_ERR(gpios); >> + } > > ... > >> + if (IS_ERR_OR_NULL(mctrl_gpio_to_gpiod(up->gpios, >> + UART_GPIO_RTS))) { > >> + } > > ... > >> - if (termios->c_cflag & CRTSCTS && up->port.flags & UPF_HARD_FLOW) { >> + if (termios->c_cflag & CRTSCTS && up->port.flags & UPF_HARD_FLOW >> + && IS_ERR_OR_NULL(mctrl_gpio_to_gpiod(up->gpios, >> + UART_GPIO_RTS))) { > >> } > > ... > >> + if (up->gpios) >> + mctrl_gpio_disable_ms(up->gpios); > > ... > >> + if (up->gpios) >> + mctrl_gpio_enable_ms(up->gpios); > > ... > >> + if (up->gpios) >> + return mctrl_gpio_get(up->gpios, &ret); > > > Can we rather make this mimic the gpiod_get_optional() API? > > So, if we get an error, it's an error, otherwise with NULL pointer the > operations goes to be no-op. > > [IS_ERR_OR_NULL() -> IS_ERR(), if (up->gpios) -> /dev/null, etc] So you want me to drop all "if (up->gpios)" checks? I can do this in some cases (e.g. serial8250_disable_ms()). But I would like to keep it in other cases, like serial8250_out_MCR(), where this check prevents some unnecessary code execution in the "non-gpios mode" (and vice-versa). Would this be acceptable? BTW: Regarding the OMAP specific code: I'm not the author of this code and I don't have access to such hardware to do some tests here. But changing IS_ERR_OR_NULL() -> IS_ERR() in this OMAP code does not seem correct. IIUTC, these "if" clauses are extended here by IS_ERR_OR_NULL(mctrl_gpio_to_gpiod()) to check if the GPIO's are not enabled / used. Currently this will probably break, since when called with "gpios == NULL", mctrl_gpio_to_gpiod() will crash [1]. If you don't object (or have other suggestions), I'll change this to use "up->gpios == 0" instead. This seems to be what the original author wanted to achieve. Okay? Thanks, Stefan [1] struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios, enum mctrl_gpio_idx gidx) { return gpios->gpio[gidx]; }