From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S941519AbcKPWy0 (ORCPT ); Wed, 16 Nov 2016 17:54:26 -0500 Received: from shards.monkeyblade.net ([184.105.139.130]:54170 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S941035AbcKPWyZ (ORCPT ); Wed, 16 Nov 2016 17:54:25 -0500 Date: Wed, 16 Nov 2016 17:54:23 -0500 (EST) Message-Id: <20161116.175423.1067471964290543367.davem@davemloft.net> To: alex.g@adaptrum.com Cc: f.fainelli@gmail.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] net/phy/vitesse: Configure RGMII skew on VSC8601, if needed From: David Miller In-Reply-To: <1479286953-11481-1-git-send-email-alex.g@adaptrum.com> References: <20161115.221217.2076182289174952941.davem@davemloft.net> <1479286953-11481-1-git-send-email-alex.g@adaptrum.com> X-Mailer: Mew version 6.7 on Emacs 25.1 / Mule 6.0 (HANACHIRUSATO) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Wed, 16 Nov 2016 13:54:55 -0800 (PST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Alexandru Gagniuc Date: Wed, 16 Nov 2016 01:02:33 -0800 > With RGMII, we need a 1.5 to 2ns skew between clock and data lines. The > VSC8601 can handle this internally. While the VSC8601 can set more > fine-grained delays, the standard skew settings work out of the box. > The same heuristic is used to determine when this skew should be enabled > as in vsc824x_config_init(). > > Tested on custom board with AM3352 SOC and VSC801 PHY. > > Signed-off-by: Alexandru Gagniuc > --- > Changes since v1: > * Added comment detailing applicability to different RGMII interfaces. Applied.