Return-path: Received: from mail-yb0-f178.google.com ([209.85.213.178]:35634 "EHLO mail-yb0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751507AbdASNNV (ORCPT ); Thu, 19 Jan 2017 08:13:21 -0500 Received: by mail-yb0-f178.google.com with SMTP id l23so17438307ybj.2 for ; Thu, 19 Jan 2017 05:11:45 -0800 (PST) Subject: Re: [PATCH v2 01/13] wil6210: add sysfs file for FTM calibration To: Lior David , "Valo, Kalle" , qca_merez References: <1484226365-10433-1-git-send-email-qca_merez@qca.qualcomm.com> <1484226365-10433-2-git-send-email-qca_merez@qca.qualcomm.com> <871svzp79p.fsf@kamboji.qca.qualcomm.com> Cc: qca_liord , "linux-wireless@vger.kernel.org" , wil6210 From: Arend Van Spriel Message-ID: (sfid-20170119_141324_712160_B1D0DF2E) Date: Thu, 19 Jan 2017 14:14:18 +0100 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=windows-1252 Sender: linux-wireless-owner@vger.kernel.org List-ID: On 19-1-2017 13:36, Lior David wrote: > On 1/19/2017 2:24 PM, Valo, Kalle wrote: >> Maya Erez writes: >> >>> From: Lior David >>> >>> In fine timing measurements, the calculation is affected by >>> 2 parts: timing of packets over the air, which is platform >>> independent, and platform-specific delays, which are dependent >>> on things like antenna cable length and type. >>> Add a sysfs file which allows to get/set these platform specific >>> delays, separated into the TX and RX components. >>> There are 2 key scenarios where the file can be used: >>> 1. Calibration - start with some initial values (for example, >>> the default values at startup), make measurements at a known >>> distance, then iteratively change the values until the >>> measurement results match the known distance. >>> 2. Adjust the delays when platform starts up, based on known >>> values. >>> >>> Signed-off-by: Lior David >>> Signed-off-by: Maya Erez >> >> Can't this go via nl80211? sysfs is not really supposed to be used for >> something like this. >> > There is no nl80211 API for this (yet?). So come up with one...? > Will it be ok to put this in debugfs? Normally this will be in the board > file (as part of RF configuration) but it will be useful to play > with these values for debugging/diagnostics. What is doing the FTM measurements? Is it all done in user-space? That would mean you also need measurement data exported to user-space. How is that done? Intel has a FTM api proposal, but it has not been submitted upstream (yet?). Regards, Arend