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 X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 998EFC63697 for ; Sun, 15 Nov 2020 15:37:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 58319223C7 for ; Sun, 15 Nov 2020 15:37:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727122AbgKOPhd (ORCPT ); Sun, 15 Nov 2020 10:37:33 -0500 Received: from vps0.lunn.ch ([185.16.172.187]:56146 "EHLO vps0.lunn.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726749AbgKOPhd (ORCPT ); Sun, 15 Nov 2020 10:37:33 -0500 Received: from andrew by vps0.lunn.ch with local (Exim 4.94) (envelope-from ) id 1keK5j-007CBo-Gz; Sun, 15 Nov 2020 16:37:23 +0100 Date: Sun, 15 Nov 2020 16:37:23 +0100 From: Andrew Lunn To: Martin Blumenstingl Cc: davem@davemloft.net, kuba@kernel.org, linux-amlogic@lists.infradead.org, devicetree@vger.kernel.org, robh+dt@kernel.org, jianxin.pan@amlogic.com, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, khilman@baylibre.com, Neil Armstrong , jbrunet@baylibre.com Subject: Re: [PATCH RFC v1 1/4] dt-bindings: net: dwmac-meson: use picoseconds for the RGMII RX delay Message-ID: <20201115153723.GA1701029@lunn.ch> References: <20201114200104.4148283-1-martin.blumenstingl@googlemail.com> <20201114200104.4148283-2-martin.blumenstingl@googlemail.com> <20201114223250.GI1480543@lunn.ch> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Nov 15, 2020 at 10:22:06AM +0100, Martin Blumenstingl wrote: > Hi Andrew, > > On Sat, Nov 14, 2020 at 11:32 PM Andrew Lunn wrote: > [...] > > > + amlogic,rgmii-rx-delay-ps: > > > + default: 0 > > > description: > > > The internal RGMII RX clock delay (provided by this IP block) in > > > - nanoseconds. When phy-mode is set to "rgmii" then the RX delay > > > + picoseconds. When phy-mode is set to "rgmii" then the RX delay > > > should be explicitly configured. When the phy-mode is set to > > > either "rgmii-id" or "rgmii-rxid" the RX clock delay is already > > > provided by the PHY. Any configuration is ignored when the > > > phy-mode is set to "rmii". > > > > Hi Martin > > > > I don't think the wording matches what the driver is actually doing: > > > > if (dwmac->rx_delay_ns == 2) > > rx_dly_config = PRG_ETH0_ADJ_ENABLE | PRG_ETH0_ADJ_SETUP; > > else > > rx_dly_config = 0; > > > > switch (dwmac->phy_mode) { > > case PHY_INTERFACE_MODE_RGMII: > > delay_config = tx_dly_config | rx_dly_config; > > break; > > case PHY_INTERFACE_MODE_RGMII_RXID: > > delay_config = tx_dly_config; > > break; > > case PHY_INTERFACE_MODE_RGMII_TXID: > > delay_config = rx_dly_config; > > break; > > case PHY_INTERFACE_MODE_RGMII_ID: > > case PHY_INTERFACE_MODE_RMII: > > delay_config = 0; > > break; > > > > So rx_delay is used for both rgmii and rgmii-txid. The binding says > > nothing about rgmii-txid. > interesting point here. it's been like this before this patch. still I > would like to understand what the proper way to fix it is so I can > also include a fix for it: > 1. should rgmii-txid not add any RX delay on the MAC side? that would > mean for my board I will switch to phy-mode rgmii so the MAC applies > both the RX and TX delays > 2. update the documentation to clarify that rgmii-txid would also add > the RX delay on the MAC side Hi Martin I would fix the documentation. > that is a good point and also a bug with one of the previous patches > I'll include a patch fixing this in v2 Thanks for looking at these. Andrew