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=-7.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,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 E1820C169C4 for ; Fri, 8 Feb 2019 15:02:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 86C2D20863 for ; Fri, 8 Feb 2019 15:02:42 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=mm-sol.com header.i=@mm-sol.com header.b="W46trkMD" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726887AbfBHPCl (ORCPT ); Fri, 8 Feb 2019 10:02:41 -0500 Received: from ns.mm-sol.com ([37.157.136.199]:50130 "EHLO extserv.mm-sol.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726813AbfBHPCl (ORCPT ); Fri, 8 Feb 2019 10:02:41 -0500 X-Greylist: delayed 472 seconds by postgrey-1.27 at vger.kernel.org; Fri, 08 Feb 2019 10:02:39 EST Received: from [192.168.27.209] (unknown [37.157.136.206]) by extserv.mm-sol.com (Postfix) with ESMTPSA id 8216ECE08; Fri, 8 Feb 2019 16:54:46 +0200 (EET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=mm-sol.com; s=201706; t=1549637686; bh=dcPQbvq/7hiwMZM4pUapZaSIoVhm0pG5ACXN9uM1WFc=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=W46trkMD4q7fSURU38goShYmZnB7vFFbku3GDWzpNvgZE2kiOCeRofKA+GpuKHLSM CG4ItJflYegZgDB0skCvmGBwBEJEnKUj+Ud6A32qVM9v/gHIegoyZy8k8SmxSnT3cv +nlV5RA0a8okqmTmjqoE7Uo+PlYhcKmbM9fM3hO75S9i3VLcldfmT83mSSgIjIFiSI igA9EzDw37OovCgcCwHbgqx8iVda4+3Om7FttIeRSbgxvKnQjuFC5xSfOeZuyPCaCn fS0cPLFt5bYojErEcLTmSiNl9CZeHW4G6gwDdnATVCXVf/yUbIr4xOpEKou1iVItZs IOoki3ZKcAwOA== Subject: Re: [PATCH] PCI: qcom: Don't deassert reset GPIO during probe To: Bjorn Andersson , Lorenzo Pieralisi , Bjorn Helgaas Cc: linux-pci@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, Khasim Syed Mohammed , Niklas Cassel , stable@vger.kernel.org References: <20190125232616.25714-1-bjorn.andersson@linaro.org> From: Stanimir Varbanov Message-ID: Date: Fri, 8 Feb 2019 16:54:44 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: <20190125232616.25714-1-bjorn.andersson@linaro.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org Hi Bjorn, Thanks for the patch! On 1/26/19 1:26 AM, Bjorn Andersson wrote: > Acquiring the reset GPIO low means that reset is being deasserted, this > is followed almost immediately with qcom_pcie_host_init() asserting it, > initializing it and then finally deasserting it again, for the link to > come up. > > Some PCIe devices requires a minimum time between the initial deassert > and subsequent reset cycles. In a platform that boots with the reset > GPIO asserted this requirement is being violated by this deassert/assert > pulse. > > Acquiring the reset GPIO high will prevent this by matching the state to > the subsequent asserted state. > > Cc: stable@vger.kernel.org > Signed-off-by: Bjorn Andersson > --- > drivers/pci/controller/dwc/pcie-qcom.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c > index d185ea5fe996..a7f703556790 100644 > --- a/drivers/pci/controller/dwc/pcie-qcom.c > +++ b/drivers/pci/controller/dwc/pcie-qcom.c > @@ -1228,7 +1228,7 @@ static int qcom_pcie_probe(struct platform_device *pdev) > > pcie->ops = of_device_get_match_data(dev); > > - pcie->reset = devm_gpiod_get_optional(dev, "perst", GPIOD_OUT_LOW); > + pcie->reset = devm_gpiod_get_optional(dev, "perst", GPIOD_OUT_HIGH); > if (IS_ERR(pcie->reset)) { > ret = PTR_ERR(pcie->reset); > goto err_pm_runtime_put; > Acked-by: Stanimir Varbanov -- regards, Stan