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 99D8FC43458 for ; Tue, 30 Jun 2026 07:11:06 +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:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=2WEvFOUe3RFPl/fYwecdyACzR7RbrE8OMXLcd2G9smQ=; b=QMZ0xmznKy1P4BLkpU5Uo20fnX nrLs95z6d7Iqte7fCnvcONqYQrQYfvGxcI6QzCHiKtywArg94urZzJBOLS7DLkw7vNdJR/YBaT0o4 2Fhix5d0/T1Ol95Urov42IMJ+i9dp04Xk2Ub8lbo5RKW8htGMsN0wqyg8tc2noVab52tRGYkfiSrz QWMoHqeuGmlW5dBLfJ24UZWZCcCCi1uDbWkzOBc0O+N68vmopWfqpMf/x/SCusfH2HgzKdXpS9MJ2 qALlh6/W05ruW4MD1e3/B4e4Rfa6Ox9o+IxjnumqJ+dkSclYb5WLahuFnSEJywjP4VHv+0fOBftJ+ 1poGcBog==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1weScU-0000000G4iq-46Mr; Tue, 30 Jun 2026 07:10:59 +0000 Received: from smtpout-02.galae.net ([185.246.84.56]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1weScQ-0000000G4hG-0Aun for linux-arm-kernel@lists.infradead.org; Tue, 30 Jun 2026 07:10:57 +0000 Received: from smtpout-01.galae.net (smtpout-01.galae.net [212.83.139.233]) by smtpout-02.galae.net (Postfix) with ESMTPS id 96E8A1A0D43; Tue, 30 Jun 2026 07:10:49 +0000 (UTC) Received: from mail.galae.net (mail.galae.net [212.83.136.155]) by smtpout-01.galae.net (Postfix) with ESMTPS id 6543F60233; Tue, 30 Jun 2026 07:10:49 +0000 (UTC) Received: from [127.0.0.1] (localhost [127.0.0.1]) by localhost (Mailerdaemon) with ESMTPSA id E7836106F1C3F; Tue, 30 Jun 2026 09:10:35 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=dkim; t=1782803447; h=from:subject:date:message-id:to:cc:mime-version:content-type: content-transfer-encoding:content-language:in-reply-to:references; bh=2WEvFOUe3RFPl/fYwecdyACzR7RbrE8OMXLcd2G9smQ=; b=ukauNkjoFa+Izzi7oPn2g0tA9q7whk8DxJSbSLP4SFqYdfTnlnKGZ1S4XqYxEEwP8ROc9E HBc0hiAPp7t+IiAp+olwJx+tnk551HcHvSjWCDN0CAqAC9n0GWw0PdeayEatvn0B87x+i2 UtCQ70rLf2WOGxPOPxiLprWMeC8InZK5XbLOStrcUyN9FT/CSPIE8djSzaSgoUsGbVtrxe ZHuWI77VuVPssz2DRPOR0uitBZkzZoNSB2PL41BJvUg7Ik0Og/41Mijhl8L8HyfqFLpmni K2yR3zqh15Dqv+kBkWLY7EwbaAqDcVbg9hQlF4vujxerOUvHat58mr27FL4SvQ== Message-ID: <0083a957-7afb-489b-b2db-de3acd71b445@bootlin.com> Date: Tue, 30 Jun 2026 09:10:34 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH net-next v9 2/6] dt-bindings: ethernet: eswin: add EIC7700 eth1 RX clock inversion variant To: 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, rmk+kernel@armlinux.org.uk, pjw@kernel.org, palmer@dabbelt.com, aou@eecs.berkeley.edu, alex@ghiti.fr, linux-riscv@lists.infradead.org, linux-stm32@st-md-mailman.stormreply.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Cc: ningyu@eswincomputing.com, linmin@eswincomputing.com, pinkesh.vaghela@einfochips.com, pritesh.patel@einfochips.com, weishangjuan@eswincomputing.com, horms@kernel.org, lee@kernel.org, wens@kernel.org References: <20260630063123.1118-1-lizhi2@eswincomputing.com> <20260630063239.1158-1-lizhi2@eswincomputing.com> From: Maxime Chevallier Content-Language: en-US In-Reply-To: <20260630063239.1158-1-lizhi2@eswincomputing.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Last-TLS-Session-Version: TLSv1.3 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260630_001054_225832_A7463089 X-CRM114-Status: GOOD ( 11.50 ) 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 Hi, On 6/30/26 08:32, lizhi2@eswincomputing.com wrote: > From: Zhi Li > > The EIC7700 SoC integrates two GMAC instances. The eth1 MAC exhibits > different RX clock sampling characteristics due to silicon-inherent > timing behavior. > > The eth1 MAC has a fixed, non-configurable RX clock-to-data skew at the > MAC input in the order of 4-5 ns. This cannot be compensated solely by > the standard MAC internal delay configuration and PHY delay, and RX clock > inversion is required at 1000Mbps for correct sampling. > > The eth1 TX path also includes a fixed silicon-inherent delay of > approximately 2 ns. This delay is always present and cannot be disabled. > It is therefore part of the effective transmit timing observed on the > wire. > > For the eth1 variant, the valid tx-internal-delay-ps values include > this fixed delay component. Consequently, the effective range becomes > 2000-4540 ps (approximately 2000 ps fixed delay plus 0-2540 ps > programmable delay). > > Introduce a dedicated compatible string > "eswin,eic7700-qos-eth-clk-inversion" to represent the eth1 variant, > allowing the driver to apply RX clock inversion only when required by > hardware variant selection. > > This keeps SoC-level differentiation without exposing silicon-fixed skew > as configurable device tree parameters. > > To reflect this, model the TX internal delay as a base 0-4540 ps range, > and constrain valid values per compatible using conditional schema rules. > > Update the binding schema as follows: > > - Define tx-internal-delay-ps as a base range: 0-4540 ps > - Add compatible-specific constraints using if/then rules: > * eswin,eic7700-qos-eth: > max 2540 ps > * eswin,eic7700-qos-eth-clk-inversion: > minimum 2000 ps (effective range 2000-4540 ps) > Maybe Andrew can help answering that one, but does it ever make sense to insert a delay beyond 2540 ps ? Maxime