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 AC10BD2A532 for ; Thu, 4 Dec 2025 20:47:59 +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:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=90lPoCGIeZvibFvI+Jj7Aj4Z4grOEkzE4KDDgVz3fS8=; b=Xah1P138LpQibmqCHbTJgi6QJn QRQMpZi4JzLZCmc+xwFMmOOl8SFzPCzQ3KMbq1I/D0YLAdVwG72c2GRIPQWYolQJSXYod69/m5ofS rLxDrfqu4ldW4BlnnrfcR10+eEq1bNH4/K7A+uRZeFg1kouvVI5raRE3jGvkpujxbxJkbnmplTlVe 2S4zIpW388i8XUDIXrzpevtWYyQwAuXyrDxddg31jR6T4ingbzWhSvn95cwNHPmqENDlTD3BozDVE yrJNuWMw1X5MlBAf6VWiBK4EihBzoMQJBfPga5tJEyRQ5Kfxm0CnDnWbZuy7mFDxnlAzKvMvoZmyt vLq1IYkg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vRGF0-00000008czN-1Df4; Thu, 04 Dec 2025 20:47:54 +0000 Received: from pandora.armlinux.org.uk ([2001:4d48:ad52:32c8:5054:ff:fe00:142]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vRGEx-00000008cyb-0Ds2; Thu, 04 Dec 2025 20:47:52 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2019; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding: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=90lPoCGIeZvibFvI+Jj7Aj4Z4grOEkzE4KDDgVz3fS8=; b=T/SIfiqDXVikO9O0tu4uZBNlLW 6PMOsEibq8S9h3DE3ovp9EN5cl/7WTTpDdxenrHdNtAeCsqlo1hH8k3dnhCJenq/VnizEzAHbCv6s crE4bj22iCna436g2Iqoqwd8IKtACPqvPCtv1jAF2/vjBryDOi2SU3fbdHxccoBbjOluy3utx/Xhr WLzi/hGK0ayRycPwbfh1gsKYrrfEUwJelwKQGGbKTdnPgalqsgXxV6zwFLfmnn50PPjzzzpceDqKh KkZX+cS2QzNka7NhIIcEV6VS232P7EO2438bRCGz1z+PS7rKgOvELaLHLkm1INShBT18CE1oSEfdU Y71n0DPQ==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:56322) by pandora.armlinux.org.uk with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.98.2) (envelope-from ) id 1vRGEh-000000003wd-1CNC; Thu, 04 Dec 2025 20:47:35 +0000 Received: from linux by shell.armlinux.org.uk with local (Exim 4.98.2) (envelope-from ) id 1vRGEc-000000001L6-1Grf; Thu, 04 Dec 2025 20:47:30 +0000 Date: Thu, 4 Dec 2025 20:47:30 +0000 From: "Russell King (Oracle)" To: Krzysztof Kozlowski Cc: Vladimir Oltean , Daniel Golle , Frank Wunderlich , Andrew Lunn , Chen Minqiang , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Matthias Brugger , AngeloGioacchino Del Regno , "Chester A. Unal" , DENG Qingfang , Sean Wang , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, netdev@vger.kernel.org Subject: Re: [PATCH v3 2/2] net: dsa: mt7530: Use GPIO polarity to generate correct reset sequence Message-ID: References: <0d85e1e6-ea75-4f20-aef1-90d446b4bfa1@kernel.org> <00f308a1-a4b1-4f20-8d8e-459ddf4c39b1@gmx.de> <20251204131626.upw77jncqfwxydww@skbuf> <4170c560-1edd-4ff8-96af-a479063be4a5@kernel.org> <20251204160247.yz42mnxvzhxas5jc@skbuf> <66d080f1-e989-451f-9d5e-34460e5eb1b0@kernel.org> <20251204171159.yy3nkvzttxecmhfo@skbuf> <178afbeb-168f-4765-bb0b-fad0bcd29382@kernel.org> <9f7da6ae-9e3e-442f-a203-28a8881dbe0f@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9f7da6ae-9e3e-442f-a203-28a8881dbe0f@kernel.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251204_124751_090709_0408D92B X-CRM114-Status: GOOD ( 19.74 ) 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 On Thu, Dec 04, 2025 at 06:32:23PM +0100, Krzysztof Kozlowski wrote: > On 04/12/2025 18:23, Krzysztof Kozlowski wrote: > > On 04/12/2025 18:11, Vladimir Oltean wrote: > >> On Thu, Dec 04, 2025 at 05:48:07PM +0100, Krzysztof Kozlowski wrote: > >>> Both are the same - inverter or NOT gate, same stuff. It is just > >>> connecting wire to pull up, not actual component on the board (although > >>> one could make and buy such component as well...). We never describe > >>> these inverters in the DTS, these are just too trivial circuits, thus > >>> the final GPIO_ACTIVE_XXX should already include whatever is on the wire > >>> between SoC and device. > >> > >> Please read what Andrew said: > >> https://lore.kernel.org/netdev/3fbc4e67-b931-421c-9d83-2214aaa2f6ed@lunn.ch/ > >> > >> Assuming there is not a NOT gate placed between the GPIO and the reset > >> pin, because the board designer decided to do that for some reason? > >> ~~~~~~~~~~~~~~ > >> > >> You two are *not* talking about the same thing. I dismissed the > > > > > > It's the same thing. NOT gate is just pulling some pin down or up. > > Although transistor would be still needed, so indeed that's still a bit > more than a wire and resistor as I implied. > > It looks like: > https://www.electronics-tutorials.ws/wp-content/uploads/2018/05/logic-log47.gif A bit more than even that... I do hope folk don't use exactly that, that's the kind of thing that would be used in "learning about electronics" projects! That's a recipe to drive a transistor into full saturation, which makes it comparitively very slow to turn off. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!