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 91876C2D0C0 for ; Fri, 27 Dec 2019 02:08:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 60A2F2080D for ; Fri, 27 Dec 2019 02:08:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="aSJqd5ME" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727368AbfL0CIY (ORCPT ); Thu, 26 Dec 2019 21:08:24 -0500 Received: from mail-pg1-f174.google.com ([209.85.215.174]:37138 "EHLO mail-pg1-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727337AbfL0CIY (ORCPT ); Thu, 26 Dec 2019 21:08:24 -0500 Received: by mail-pg1-f174.google.com with SMTP id q127so13734266pga.4 for ; Thu, 26 Dec 2019 18:08:23 -0800 (PST) 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=/jmHtZlQnSdY2QigopVkjawZyj3M/3UiiMQeaTFLc+I=; b=aSJqd5MEqTe9DNv9X5vNTABjMWatTf8LgM5Ipt9m1Lqn/9XHK2ydl+64I67R0MN52H j6Hj6PTgqLgJFOGWDCIP3/IwKa4elTuKmdekkXA74LnKNQihyMbZ6P6ORbExRgBDMUlc 3qHBYgixTVshoYBOB+KKphcjWCpCdG5zTsZBfgP6xOTfhpbhStFWvFeZp0S7BPfcV4Cy NR4CeyIRwiRSiCySXECZFpe79vNAJ3ayYMruiXMo4zO/RtJzhM524Wnwb+JNRHZLwlck 0LUBrWL7eUUfOsCQuvWxf4FKItmy3x0DDcRMlVPW+yQLd8JtGH+661itNaI9Ndo6FsAk 2V3Q== 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=/jmHtZlQnSdY2QigopVkjawZyj3M/3UiiMQeaTFLc+I=; b=AkWbsPPKjJMgOGfMYkHwDYy2FF3yDH/psXc1d24wErkSXvvmYRZoazkBL1KVW7Zbgc Xb6HChU4ZV4vQXvx5e3sB/G7Vy+lIzGdZqb+jZAZzJPXymqrJioDncnv2RoFr8ClnAe+ kg4yC6NreUvXZ7fz4DjqBGbxysip1bS7jOG+JLo++l/qKbQaiteV2l2uhumY4C/YVW1H CEJ5pDvQPOdvrhI3yynS/ke9HCvUjrV4Q6Kwly+TF2pNP85t5e5wMoIkGkD+DEtKMufH yzFFUx8AT92hg5Gc0FJji0GXI534UExX+3kogRpCaMmy3j6Trduh3SXeJzGDGGhU0aQw Zj9Q== X-Gm-Message-State: APjAAAXGMPSx9sVr+99IscQ3A4Suz04cQ6qFoXM2ZNTEL7m0z2WoLGTO l6SK8gjYsZ9aR4ibza6Rixw= X-Google-Smtp-Source: APXvYqxHhrvwVKyNDjwnu6yXNn/qQQ4U+HBUrPcbySQ0E4iZmhRp3B3EXm+iFUjmqGm3hUWy2wSGYw== X-Received: by 2002:aa7:90c5:: with SMTP id k5mr15941113pfk.143.1577412503667; Thu, 26 Dec 2019 18:08:23 -0800 (PST) Received: from localhost (c-73-241-114-122.hsd1.ca.comcast.net. [73.241.114.122]) by smtp.gmail.com with ESMTPSA id 7sm28436320pfx.52.2019.12.26.18.08.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 26 Dec 2019 18:08:22 -0800 (PST) Date: Thu, 26 Dec 2019 18:08:20 -0800 From: Richard Cochran To: "Y.b. Lu" Cc: Vladimir Oltean , netdev , "David S . Miller" , Claudiu Manoil , Vladimir Oltean , Alexandre Belloni , Microchip Linux Driver Support Subject: Re: [PATCH] net: mscc: ocelot: support PPS signal generation Message-ID: <20191227020820.GA6970@localhost> References: <20191226095851.24325-1-yangbo.lu@nxp.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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 Thu, Dec 26, 2019 at 11:17:26AM +0000, Y.b. Lu wrote: > > -----Original Message----- > > From: Vladimir Oltean > > Also, I think what you have implemented here is periodic output > > (PTP_CLK_REQ_PEROUT) not PPS [input] (PTP_CLK_REQ_PPS). I have found > > the PTP documentation to be rather confusing on what PTP_CLK_REQ_PPS > > means, so I'm adding Richard in the hope that he may clarify (also > > what's different between PTP_CLK_REQ_PPS and PTP_CLK_REQ_PPS). The PTP_CLK_REQ_PPS is for generating events for the kernel's PPS subsystem. (See drivers/pps). This has nothing to do with actual PPS signals. > My understand is PTP_CLK_REQ_PEROUT is for periodical output, Yes. > and PTP_CLK_REQ_PPS is for PPS event handling. No. Some cards generate an interrupt at the full second roll over. The interrupt service routine can feed a system time stamp into the kernel's pps subsystem for use by NTP. If your device is generating an actual PPS output signal, then you should implement the PTP_CLK_REQ_PEROUT method. Bonus points for making the signal fully programmable! Thanks, Richard