From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from pandora.armlinux.org.uk (pandora.armlinux.org.uk [78.32.30.218]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 561E91F5E6; Thu, 4 Dec 2025 20:47:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=78.32.30.218 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764881270; cv=none; b=cPdbtLlbEfJwiNWnK268JEEOxz/MJi39pTo6Yq9oo6cXMWXY+S1kJ74mQ5lx2B/xSR6tN/024lkeEkA0KivrX9kpdMl3EuNfV0dtnuaKbZaJS1FJBX2miXYcAx+/df21aAA3FCQSf6bTMVwrHRBd8owipa7WC/xw7DY4bmSlCYk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764881270; c=relaxed/simple; bh=DZNGbBIFwdBhALOb0N5Gy3FQ7YOyC1fjB7NsyJoZj7U=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=LZ39PNUxvPHGzDPDYXlQOL/ZjbNXVcsyBw06cgK0sxLPLQpNXkJqtgRm1+IxOuTut+P8wu5uY3qctsSAE1VHfUpdgzoyeBLJxcy0zjZELmBtJdUBHB3e7vkHHKFZkmZa5VLlFK0I3Bo3kevnqtA1viEBRd+nmfOv/beJTvjIId0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=armlinux.org.uk; spf=none smtp.mailfrom=armlinux.org.uk; dkim=pass (2048-bit key) header.d=armlinux.org.uk header.i=@armlinux.org.uk header.b=T/SIfiqD; arc=none smtp.client-ip=78.32.30.218 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=armlinux.org.uk Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=armlinux.org.uk Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=armlinux.org.uk header.i=@armlinux.org.uk header.b="T/SIfiqD" 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> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9f7da6ae-9e3e-442f-a203-28a8881dbe0f@kernel.org> Sender: Russell King (Oracle) 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!