From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753238AbbBYRbC (ORCPT ); Wed, 25 Feb 2015 12:31:02 -0500 Received: from mail-wi0-f182.google.com ([209.85.212.182]:44390 "EHLO mail-wi0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752120AbbBYRa7 (ORCPT ); Wed, 25 Feb 2015 12:30:59 -0500 Date: Wed, 25 Feb 2015 18:30:53 +0100 From: Richard Cochran To: Stathis Voukelatos Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org, devicetree@vger.kernel.org Subject: Re: [PATCH net-next v4 0/3] Linn Ethernet Packet Sniffer driver Message-ID: <20150225173053.GE7703@localhost.localdomain> References: <20150225151945.GB7703@localhost.localdomain> <20150225170127.GD7703@localhost.localdomain> <54EE0268.2040201@linn.co.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <54EE0268.2040201@linn.co.uk> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Feb 25, 2015 at 05:12:08PM +0000, Stathis Voukelatos wrote: > Regarding this last point, the actual counter that generates the > timestamps is not part of the sniffer H/W module. Timestamps are > provided to the sniffer externally in H/W by a different module. > Apart of that there is not eg. a sniffer register to read the > current counter value. I wonder if it should be the driver for the > module where the counter belongs (called Event Timer in the > Pistachio Soc) that should register the PHC. It is okay to have the PHC come from another driver. However, you do need to export PHC index to the time stamping code, in order to provide the 'phc_index' field for the ETHTOOL_GET_TS_INFO request. You can also have one SW driver cover both HW modules, if that is cleaner and easier. Among all the other drivers, only gianfar has the PHC separate. > I need some more time to study your other suggestions regarding the > PHY timestamping framework. >>From my (limited) understanding of your HW device, I should think that it will work. The PHY time stamping subsystem is not the most obvious code in the world. Please feel free to ask if you have any questions. Thanks, Richard