From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.gentoo.org (woodpecker.gentoo.org [140.211.166.183]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C68E2221FAA; Thu, 24 Apr 2025 10:05:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=140.211.166.183 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745489121; cv=none; b=XLSk+8350NV6pmAjNirWlX62LZRvJ7SL064kisXXVLM9AZHq7I1sEVxvFhqDCgHSEvyWmznGxFQQROinlxpMpLmtwDj8FSSeTnm54662KyH14we1uYfJV0kMFt/TY3OEsjxCCIMCKvNuCrJeFBq4YMhA16v0wf5tPof0Oq386Jk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745489121; c=relaxed/simple; bh=IkAVQLQcbBsqd++RWlxWPNV68rQ02JZMdcpF9vVK4mw=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=CbRqZZoeCQK+uYeRVwHsVHvtGEKFRY/Cjx44j/4npEGqdCUtBoDG6E1349crFRJXad7RMQkT7DNG/bBLcXIKoL5u6jhuZAgAsFfVTCXfPXE+7jYDRJnUl+K+kQ1TZ0s8bu4lYKsjDXWd/AcNbLOCbme9yaG+xuxApQbxvHLMi6A= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gentoo.org; spf=pass smtp.mailfrom=gentoo.org; arc=none smtp.client-ip=140.211.166.183 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gentoo.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gentoo.org Received: from localhost (unknown [116.232.18.95]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (prime256v1) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: dlan) by smtp.gentoo.org (Postfix) with ESMTPSA id 9CCA2340DF9; Thu, 24 Apr 2025 10:05:18 +0000 (UTC) Date: Thu, 24 Apr 2025 10:05:14 +0000 From: Yixun Lan To: Andre Przywara Cc: Andrew Lunn , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Chen-Yu Tsai , Jernej Skrabec , Samuel Holland , Maxime Ripard , Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-sunxi@lists.linux.dev, linux-kernel@vger.kernel.org, netdev@vger.kernel.org Subject: Re: [PATCH 4/5] arm64: dts: allwinner: a527: add EMAC0 to Radxa A5E board Message-ID: <20250424100514-GYA48784@gentoo> References: <20250423-01-sun55i-emac0-v1-0-46ee4c855e0a@gentoo.org> <20250423-01-sun55i-emac0-v1-4-46ee4c855e0a@gentoo.org> <20250424014120.0d66bd85@minigeek.lan> Precedence: bulk X-Mailing-List: devicetree@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: <20250424014120.0d66bd85@minigeek.lan> Hi Andrew, Andre, On 01:42 Thu 24 Apr , Andre Przywara wrote: > On Wed, 23 Apr 2025 18:58:37 +0200 > Andrew Lunn wrote: > > Hi, > > > > +&emac0 { > > > + phy-mode = "rgmii"; > > > > Does the PCB have extra long clock lines in order to provide the > > needed 2ns delay? I guess not, so this should be rgmii-id. > > That's a good point, and it probably true. > > > > > > + phy-handle = <&ext_rgmii_phy>; > > > + > > > + allwinner,tx-delay-ps = <300>; > > > + allwinner,rx-delay-ps = <400>; > > > > These are rather low delays, since the standard requires 2ns. Anyway, > > once you change phy-mode, you probably don't need these. > As I tested, drop these two properties making ethernet unable to work, there might be some space to improve, but currently I'd leave it for now > Those go on top of the main 2ns delay, I guess to accommodate some skew > between the RX and TX lines, or to account for extra some PCB delay > between clock and data? The vendor BSP kernels/DTs program those board > specific values, so we have been following suit for a while, for the > previous SoCs as well. > I just tried, it also works with some variations of those values, but > setting tx-delay to 0 stops communication. > I'd not bother to try other combinations, and just stick to vendor's settings thanks -- Yixun Lan (dlan)