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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AA435C433F5 for ; Mon, 1 Nov 2021 14:58:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 88EAF60EE3 for ; Mon, 1 Nov 2021 14:58:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232223AbhKAPBV (ORCPT ); Mon, 1 Nov 2021 11:01:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35126 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231304AbhKAPBS (ORCPT ); Mon, 1 Nov 2021 11:01:18 -0400 Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1E704C061714 for ; Mon, 1 Nov 2021 07:58:45 -0700 (PDT) Received: from gallifrey.ext.pengutronix.de ([2001:67c:670:201:5054:ff:fe8d:eefb] helo=[IPv6:::1]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1mhYle-0005LQ-1T; Mon, 01 Nov 2021 15:58:34 +0100 Message-ID: <557e68ad15634ddb65c98ebf80cd7ef962ac2608.camel@pengutronix.de> Subject: Re: [PATCH v2 RESEND] PCI: imx6: Replace legacy gpio interface for gpiod interface From: Lucas Stach To: =?ISO-8859-1?Q?Ma=EDra?= Canal Cc: hongxing.zhu@nxp.com, lorenzo.pieralisi@arm.com, robh@kernel.org, Bjorn Helgaas , Bjorn Helgaas , shawnguo@kernel.org, s.hauer@pengutronix.de, kernel@pengutronix.de, linux-imx@nxp.com, linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Date: Mon, 01 Nov 2021 15:58:31 +0100 In-Reply-To: References: <4f1b60bab451b219c7139e2204eb5b9f462ee4e0.camel@pengutronix.de> Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.40.4 (3.40.4-1.fc34) MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SA-Exim-Connect-IP: 2001:67c:670:201:5054:ff:fe8d:eefb X-SA-Exim-Mail-From: l.stach@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Am Montag, dem 01.11.2021 um 11:44 -0300 schrieb Maíra Canal: > ? > > > /* Some boards don't have PCIe reset GPIO. */ > > > - if (gpio_is_valid(imx6_pcie->reset_gpio)) { > > > - gpio_set_value_cansleep(imx6_pcie->reset_gpio, > > > + if (imx6_pcie->reset_gpio) { > > > + gpiod_set_value_cansleep(imx6_pcie->reset_gpio, > > > imx6_pcie->gpio_active_high); > > > msleep(100); > > > - gpio_set_value_cansleep(imx6_pcie->reset_gpio, > > > + gpiod_set_value_cansleep(imx6_pcie->reset_gpio, > > > !imx6_pcie->gpio_active_high); > > > > I don't think this is correct. gpiod_set_value sets the logical line > > state, so if the GPIO is specified as active-low in the DT, the real > > line state will be negated. The only reason why the reset-gpio-active- > > high property even exists is that old DTs might specify the wrong GPIO > > polarity in the reset-gpio DT description. I think you need to use to > > gpiod_set_raw_value API here to get the expected real line state even > > with a broken DT description. > > > > Regards, > > Lucas > > > > I'm a beginner in kernel development, so I'm sorry for the question. > If I change gpiod_set_value_cansleep for gpiod_set_raw_value, wouldn't > I change the behavior of the driver? I replaced > gpio_set_value_cansleep for gpiod_set_value_cansleep because they have > the same behavior and I didn't change the logic states. Thank you for > the feedback! Yes, you need to use the _cansleep variant of the API to keep the context information. The point I was trying to make was that you probably (please double check, that's just an assumption on my side) need to use the _raw variant of the gpiod API to keep the current behavior of the driver, as we are setting the physical line state purely depending on the reset-gpio-active-high property presence, not the logical line state, which would take into account the polarity specified in the DT gpio descriptor. I guess the right API call here would be gpiod_set_raw_value_cansleep(). Regards, Lucas