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 03E39220F2C; Sat, 10 Jan 2026 18:26:15 +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=1768069578; cv=none; b=WEg6JB63Fc1aDG5bYdujD8FdLBDCRojOeEsrU6Fpr3NuqgYoonOqLsB7i5EbFf2dZTOb/157b+o4Q3/MDlWUx079rUBqDoRDQIq1cbdmcKaT3gtIILr3wZhsClIKSN5Pf6ZtobO1fxwGby3fRYC0Gz1sQOQvhmdvia5j775LeCk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768069578; c=relaxed/simple; bh=vb3HbPLvdOKDzl+M49x3RuXEN7RG+GiSw/mrMS92RTA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=E0B8VSf8GWmV9G2IXBQ5cgpG1M1ngUcgznyYAdh8gWuS5XisC5HAa6D7qbEFqyPU4+7h7J0+++XVwFoSqKfIwGamYSW7tM91l7sAG+nKikzItjFWwAi2BSnlmc0lGkBnzmGZmrbxf83Qz/P5HO9NsPzQZyql8u0n5hXM7Wd3grs= 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=TBBkE6S2; 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="TBBkE6S2" 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=afgUmo7FVA0UMa1pCZgDdfCcrRnZeK5e78tq9RhRkhg=; b=TBBkE6S2viMmModJ7gC/H2/pmC VyCBuAULdIlBeFeTHMiw1k0FI9FcdG6ZYI1BUln5cJKJ7zM3IO/0Yu/jwaGbWHXh3HRxNGi2rvjC0 Hz0BCuDbZYud3yTnPz8zwu+7fJzcw/sRSA+e3NdIRcGs1gh00G9p+549BbloBiq8ABhDnCErrYaTQ XU9rKs5jr5RWGdDFmocUJ9eDG56euyzXR2k6wQsPSkbZPJO3RsBcoAUlpiNd4mxtrNGTiokRmhwCg WmrJJK+oGJstSjolh+TcadHGN2n34Haq7qdOFJIgfYLrosyn5nVPStr8/UkuueO07+wegHmnt049j ElqpB2aA==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:44118) 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 1vedf7-000000004ui-3O08; Sat, 10 Jan 2026 18:26:10 +0000 Received: from linux by shell.armlinux.org.uk with local (Exim 4.98.2) (envelope-from ) id 1vedf3-000000004St-0Hpf; Sat, 10 Jan 2026 18:26:05 +0000 Date: Sat, 10 Jan 2026 18:26:04 +0000 From: "Russell King (Oracle)" To: Andrew Lunn Cc: lizhi2@eswincomputing.com, devicetree@vger.kernel.org, andrew+netdev@lunn.ch, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, robh@kernel.org, krzk+dt@kernel.org, conor+dt@kernel.org, netdev@vger.kernel.org, pabeni@redhat.com, mcoquelin.stm32@gmail.com, alexandre.torgue@foss.st.com, linux-stm32@st-md-mailman.stormreply.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, ningyu@eswincomputing.com, linmin@eswincomputing.com, pinkesh.vaghela@einfochips.com, weishangjuan@eswincomputing.com Subject: Re: [PATCH v1 1/2] dt-bindings: ethernet: eswin: add clock sampling control Message-ID: References: <20260109080601.1262-1-lizhi2@eswincomputing.com> <20260109080859.1285-1-lizhi2@eswincomputing.com> <00b7b42f-2f9d-402a-82f0-21641ea894a1@lunn.ch> Precedence: bulk X-Mailing-List: linux-kernel@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: <00b7b42f-2f9d-402a-82f0-21641ea894a1@lunn.ch> Sender: Russell King (Oracle) On Fri, Jan 09, 2026 at 07:27:54PM +0100, Andrew Lunn wrote: > > rx-internal-delay-ps: > > - enum: [0, 200, 600, 1200, 1600, 1800, 2000, 2200, 2400] > > + enum: [0, 20, 60, 100, 200, 400, 800, 1600, 2400] > > > > tx-internal-delay-ps: > > - enum: [0, 200, 600, 1200, 1600, 1800, 2000, 2200, 2400] > > + enum: [0, 20, 60, 100, 200, 400, 800, 1600, 2400] > > You need to add some text to the Changelog to indicate why this is > safe to do, and will not cause any regressions for DT blobs already in > use. Backwards compatibility is very important and needs to be > addressed. > > > + eswin,rx-clk-invert: > > + description: > > + Invert the receive clock sampling polarity at the MAC input. > > + This property may be used to compensate for SoC-specific > > + receive clock to data skew and help ensure correct RX data > > + sampling at high speed. > > + type: boolean > > This does not make too much sense to me. The RGMII standard indicates > sampling happens on both edges of the clock. The rising edge is for > the lower 4 bits, the falling edge for the upper 4 bits. Flipping the > polarity would only swap the nibbles around. I'm going to ask a rather pertinent question. Why do we have this eswin stuff in the kernel tree? I've just been looking to see whether I can understand more about this, and although I've discovered the TRM is available for the EIC7700: https://github.com/eswincomputing/EIC7700X-SoC-Technical-Reference-Manual/releases that isn't particularly helpful on its own. There doesn't appear to be any device tree source files that describe the hardware. The DT bindings that I can find seem to describe only ethernet and USB. describe the ethernet and USB, and maybe sdhci. I was looking for something that would lead me to what this eswin,hsp-sp-csr thing is, but that doesn't seem to exist in our DT binding documentation, nor does greping for "hsp.sp.csr" in arch/*/boot/dts find anything. So, we can't know what this "hsp" thing is to even know where to look in the 80MiB of PDF documentation. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!