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=-2.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 3E999C3A59E for ; Wed, 21 Aug 2019 14:08:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 105022339E for ; Wed, 21 Aug 2019 14:08:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="sWF8XKfs" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729131AbfHUOIU (ORCPT ); Wed, 21 Aug 2019 10:08:20 -0400 Received: from mail-pf1-f194.google.com ([209.85.210.194]:45304 "EHLO mail-pf1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726484AbfHUOIT (ORCPT ); Wed, 21 Aug 2019 10:08:19 -0400 Received: by mail-pf1-f194.google.com with SMTP id w26so1496495pfq.12; Wed, 21 Aug 2019 07:08:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=DfIwMjuye46lrWu38aFKyCCnR8npSE/y3cObQoGGmVI=; b=sWF8XKfsPmFxZ7v+A7/UE/8lyDs/keMDWMO0Ptcp4dNz/tII1laWgfvyekP+ZVtSP/ iii0j+YUecSY9mZvMwjMS87OJcbP5r8SKrywOSnZD+IFcDFCNUJxwp304rR97qSHN3jG kqBSroNjZm1Bo5sNUTGzisMu0mWveZj/ra7ZNsFbP1ZdFQU6G8IjvQutBY0+07A1cYgo YkSGL1eOgYJPYUf2rAUcMS+CF05hnV7zlTeOlZ8omjqOanPE/AAdyRWIFFqBr68uzYp0 MeycER8/OcTYdr40pN71I5hrYbwTL+aQZl5AVJDdwGufgCBJvvCUSjx3hPTcVZ0SUdr8 ByDQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=DfIwMjuye46lrWu38aFKyCCnR8npSE/y3cObQoGGmVI=; b=jJ+SsUpVv3i5K5qFAUsm+QEasoNWrTGpvuHwV1VGQ1UfZNqxP8+3SptYbRiaKHiYxW hMdHMCO7yZagt8MvgU+So0kHLYKZaEiiCv7f8daYK8HVya3bvFuwZesOHRAjoV5jH6UO xqN6zT1/uCOjfOz9DGJMTFmCO+R86Twx3lRKNWPsnuesiWzRnEVz+vOx/6lXEveuyRtq IipzRC7bLmZ1rEQlajMQRXcSM9t1DlnBHXiUQJo75k8e8iy4Z7uOYT/Z7uiCa0q+sO9z CPJ6zIksJgfd5yzmW18oZIKFTF4dDuvOIC0Sy+4K+4WgbqEvI/jnBOcA8fV9YVo54XGE Y5dA== X-Gm-Message-State: APjAAAUVNT6VORd2Og4g/Xzbi5A+NrwC1uqonvbn9G9Uqc2lNiu8ATuz kPgETYMPJi6lEHh9NeO52/k= X-Google-Smtp-Source: APXvYqyrQiwKGjDEac4IuaAOQuYhXBIfoqSas+0eApLSYs7UiWACl7R6cF7QbWH9y7YCC0qnPjxhtQ== X-Received: by 2002:a17:90a:8d85:: with SMTP id d5mr125889pjo.137.1566396499032; Wed, 21 Aug 2019 07:08:19 -0700 (PDT) Received: from localhost (c-73-222-71-142.hsd1.ca.comcast.net. [73.222.71.142]) by smtp.gmail.com with ESMTPSA id a26sm24722808pff.174.2019.08.21.07.08.16 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 21 Aug 2019 07:08:17 -0700 (PDT) Date: Wed, 21 Aug 2019 07:08:15 -0700 From: Richard Cochran To: Vladimir Oltean Cc: Mark Brown , Hubert Feurstein , mlichvar@redhat.com, Andrew Lunn , Florian Fainelli , linux-spi@vger.kernel.org, netdev Subject: Re: [PATCH spi for-5.4 0/5] Deterministic SPI latency with NXP DSPI driver Message-ID: <20190821140815.GA1447@localhost> References: <20190818182600.3047-1-olteanv@gmail.com> <20190821043845.GB1332@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190821043845.GB1332@localhost> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Tue, Aug 20, 2019 at 09:38:45PM -0700, Richard Cochran wrote: > Overall, the PTP switch use case is well supported by Linux. The > synchronization of the management CPU to the PTP, while nice to have, > is not required to implement a Transparent Clock. Your specific > application might require it, but honestly, if the management CPU > needs good synchronization, then you really aught to feed a PPS from > the switch into a gpio (for example) on the CPU. Another way to achieve this is to have a second MAC interface on the management CPU connected to a spare port on the switch. Then time stamping, PHC, ptp4l, and phc2sys work as expected. Thanks, Richard