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 B154AC61DBD for ; Thu, 27 Aug 2026 02:46:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=E+guPjHorPXFsywNBSf8zOIVLbuJKgJ+G813yEPFdfI=; b=iY6Zaxpkj5iIgH Lh0nb3oqtfVHF0U7z18CQd77oAJQ+UnpItoXnkezmMwMHd9stKWjqrJwkcP3aTqkUUAw2xgmqo8BH e8sc+paOWcTSBOHy/d0lmew2GuHs45sVF8NHt2a0Y7mXk1Ie81iSwSJZeSGr1SqydnTZj1emoqIIx ZTdShb3OcIwFTI7bJHdpojgG2l6uEbLaS18a9URvIMyIXPwiFw0cExoOlDq2z6v2+V5wLBh1C6aRg 6ZuV/Ad7sBf3CzodkJ6jfJCyCg6HdDjZRxpA9+c8uyiA89yef1u08akM2mLMAJZw0d/PrYrxlay3D 1/c8IdfKGpfvwO3TP04A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wzQ8K-00000003K1a-0tE6; Thu, 27 Aug 2026 02:46:28 +0000 Received: from vps0.lunn.ch ([156.67.10.101]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wzQ8H-00000003K0t-3Tg1 for linux-riscv@lists.infradead.org; Thu, 27 Aug 2026 02:46:27 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lunn.ch; s=20171124; h=In-Reply-To:Content-Disposition:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:From:Sender:Reply-To:Subject: Date:Message-ID:To:Cc:MIME-Version:Content-Type:Content-Transfer-Encoding: Content-ID:Content-Description:Content-Disposition:In-Reply-To:References; bh=04LV//Qqu8AJccIRCStGRzmejSwdi5G60bO+SIOXoKQ=; b=amLerCpJ/Smpy9mCR2c6EZPLHv 8uYNlnRnUKBmnI/Ik/B6ExblrZ0E0hP0t5flRLXUxlTF+bCL+0zEb7IaU7FHed2bHZoyz+yMLx5pW CubhHcNuReLflxAQkihRVcoCssPUMZXohqnEYx3yVGuyPYmb/jXd+dpuk9HAujgNRRX0=; Received: from andrew by vps0.lunn.ch with local (Exim 4.94.2) (envelope-from ) id 1wzQ7t-001arp-R8; Thu, 27 Aug 2026 04:46:01 +0200 Date: Thu, 27 Aug 2026 04:46:01 +0200 From: Andrew Lunn To: Jia Wang Cc: Rob Herring , Krzysztof Kozlowski , Conor Dooley , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti , Daniel Lezcano , Thomas Gleixner , Samuel Holland , Anup Patel , Mark Brown , Andi Shyti , Mika Westerberg , Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Alexandre Torgue , Giuseppe Cavallaro , Jose Abreu , Eugeniy Paltsev , Vinod Koul , Frank Li , Paul Walmsley , Palmer Dabbelt , Conor Dooley , devicetree@vger.kernel.org, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, linux-spi@vger.kernel.org, linux-i2c@vger.kernel.org, netdev@vger.kernel.org, dmaengine@vger.kernel.org Subject: Re: [PATCH 11/12] riscv: dts: ultrarisc: Add Shenzhen Rongda M0 board device tree Message-ID: References: <20260824-ultrarisc-dts-v1-0-61ab7aebe9e5@ultrarisc.com> <20260824-ultrarisc-dts-v1-11-61ab7aebe9e5@ultrarisc.com> <178779718359.1423015.16616466921659081322.b4-reply@b4> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <178779718359.1423015.16616466921659081322.b4-reply@b4> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260826_194625_868044_1F347841 X-CRM114-Status: GOOD ( 20.73 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org On Thu, Aug 27, 2026 at 10:19:43AM +0800, Jia Wang wrote: > On 2026-08-24 15:02 +0200, Andrew Lunn wrote: > > > +ðernet { > > > + phy-handle = <&phy0>; > > > + /* > > > + * YT8531 RGMII timing on this board requires no PHY internal delays. > > > > Please extend this sentence with an explanation why it needs no delay? > > > > There are times this is correct, but it is also mostly wrong. Without > > an explanation, i cannot say if this is correct or not. > > > > Thanks for the review. > > The DP1000 SoC integration provides the required TX and RX RGMII clock > skew, so enabling the YT8531 internal delays would apply the delay twice. Please take a read of https://elixir.bootlin.com/linux/v6.15/source/Documentation/devicetree/bindings/net/ethernet-controller.yaml#L287 You need to make the MAC driver do the correct thing: # There are a small number of cases where the MAC has hard coded # delays which cannot be disabled. The 'phy-mode' only describes the # PCB. The inability to disable the delays in the MAC does not change # the meaning of 'phy-mode'. It does however mean that a 'phy-mode' of # 'rgmii' is now invalid, it cannot be supported, since both the PCB # and the MAC and PHY adding delays cannot result in a functional # link. Thus the MAC should report a fatal error for any modes which # cannot be supported. When the MAC implements the delay, it must # ensure that the PHY does not also implement the same delay. So it # must modify the phy-mode it passes to the PHY, removing the delay it # has added. Failure to remove the delay will result in a # non-functioning link. Andrew _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv