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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 3D98DCCFA13 for ; Fri, 7 Nov 2025 03:01:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:To:Subject:Cc:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=zVsNu3y1SfXzBdfw48QrW2mnVPUuj41sgD9Q3ySf0jw=; b=dJHvF9bYgAdY8/07nmDZQ/mNvl eYBlsgf8jYmCl44AI0xBf7Ieg8LBFeV3JPDh4hb9bY2Xr+/llGorhB28J3LxfVc7EAzYOCRY6W4EC iikGAFBIlCkoVbvdF44yDk2rSY3QHVEow30afJX1zBEXBD+m5agDg9XkpGPgQhnS+6qw7mE1It64d wYYrJ4hwmcKbU9zeORGwddmirrAWM/A4OzXOiR9NKzZmz5tPCTtWBpLl3BmPdQc/eI9lSBRY7FSnr mxR72zDFwSFkmUUIQ6pKg7LP8KJgxpUjgA3SKn/y1wBjsyVVAJxp88/dtTpHMWWNa+1tm6f0fUNEZ v7h8q8eQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vHCix-0000000GbCa-2WY9; Fri, 07 Nov 2025 03:01:15 +0000 Received: from mail-m1973187.qiye.163.com ([220.197.31.87]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vHCis-0000000GbBy-3FwM; Fri, 07 Nov 2025 03:01:13 +0000 Received: from [172.16.12.129] (unknown [58.22.7.114]) by smtp.qiye.163.com (Hmail) with ESMTP id 28b7d0bc4; Fri, 7 Nov 2025 11:01:05 +0800 (GMT+08:00) Message-ID: Date: Fri, 7 Nov 2025 11:01:04 +0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Cc: shawn.lin@rock-chips.com, Lorenzo Pieralisi , =?UTF-8?Q?Krzysztof_Wilczy=C5=84ski?= , Manivannan Sadhasivam , Rob Herring , Bjorn Helgaas , Heiko Stuebner , linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, Krzysztof Kozlowski , Conor Dooley , Johan Jonker , linux-rockchip@lists.infradead.org Subject: Re: [PATCH] arm64: dts: rockchip: align bindings to PCIe spec To: Geraldo Nascimento , Ye Zhang References: <4b5ffcccfef2a61838aa563521672a171acb27b2.1762321976.git.geraldogabriel@gmail.com> <67b605b0-7046-448a-bc9b-d3ac56333809@rock-chips.com> From: Shawn Lin In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-HM-Tid: 0a9a5c42adf909cckunmd8a05e02f6b7ea X-HM-MType: 1 X-HM-Spam-Status: e1kfGhgUHx5ZQUpXWQgPGg8OCBgUHx5ZQUlOS1dZFg8aDwILHllBWSg2Ly tZV1koWUFDSUNOT01LS0k3V1ktWUFJV1kPCRoVCBIfWUFZQkIaTlYfTkwdH0JKSxgYSE1WFRQJFh oXVRMBExYaEhckFA4PWVdZGBILWUFZTkNVSUlVTFVKSk9ZV1kWGg8SFR0UWUFZT0tIVUpLSU9PT0 hVSktLVUpCS0tZBg++ DKIM-Signature: a=rsa-sha256; b=N/AjtPdWxmqb/pFSs6gykwYAJznoZ8eog/K1ggyHgiHswHpN2h06IuYOiipUjuL3fkrH9tNI7iUErn2M+xn58GJHlBeesAuUuwLcF7xohvnZc6VYwGmJh+ip2Ox71RepKsnJaUNoX4XVoE81ZYMa3tVHxJcOI2tPNeo7AAFKCxQ=; c=relaxed/relaxed; s=default; d=rock-chips.com; v=1; bh=zVsNu3y1SfXzBdfw48QrW2mnVPUuj41sgD9Q3ySf0jw=; h=date:mime-version:subject:message-id:from; X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251106_190111_329054_269A3CB1 X-CRM114-Status: GOOD ( 10.83 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org + Ye Zhang 在 2025/11/07 星期五 10:43, Geraldo Nascimento 写道: > On Wed, Nov 05, 2025 at 04:56:36PM +0800, Shawn Lin wrote: >> 在 2025/11/05 星期三 16:18, Geraldo Nascimento 写道: >>> Hi Shawn, glad to hear from you. >>> >>> Perhaps the following change is better? It resolves the issue >>> without the added complication of open drain. After you questioned >>> if open drain is actually part of the spec, I remembered that >>> GPIO_OPEN_DRAIN is actually (GPIO_SINGLE_ENDED | GPIO_LINE_OPEN_DRAIN) >>> so I decided to test with just GPIO_SINGLE_ENDED and it works. > > Shawn, > > I quote from the PCIe Mini Card Electromechanical Specification Rev 1.2 > > "3.4.1. Logic Signal Requirements > > The 3.3V card logic levels for single-ended digital signals (WAKE#, > CLKREQ#, PERST#, and W_DISABLE#) are given in Table 3-7. [...]" > > So while you are correct that PERST# is most definitely not Open Drain, > there's evidence on the spec that defines this signal as Single-Ended. > This's true. But I couldn't find any user in dts using either GPIO_SINGLE_ENDED or GPIO_OPEN_DRAIN for PCIe PERST#. I'm curious how these two flags affect actual behavior of chips. Ye, could you please help check it? > Thanks, > Geraldo Nascimento >