From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from skprod3.natinst.com ([130.164.80.24]:34726 "EHLO ni.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751177AbbEEWLm (ORCPT ); Tue, 5 May 2015 18:11:42 -0400 Message-ID: <5549401A.4080800@ni.com> Date: Tue, 05 May 2015 17:11:38 -0500 From: Xander Huff MIME-Version: 1.0 To: lars@metafoo.de CC: Jaeden Amero , Josh Cartwright , Joseph Hershberger , linux-iio@vger.kernel.org Subject: XADC values read from VAUX0-15 are consistently ~10% less than they should be Content-Type: text/plain; charset=utf-8; format=flowed Sender: linux-iio-owner@vger.kernel.org List-Id: linux-iio@vger.kernel.org Hi Lars, I've been working on transitioning one of our hardware devices over from using the out-of-tree hwmon driver that Xilinx used to provide to the xadc driver you added upstream, but I've been having trouble accessing our connected auxiliary channels. I've found that for all channels I've tested, after multiplying the raw value by the scale value (0.244140625), the resulting mVs are always about 10 percent less than what we expect them to be. (2.9V instead of 3.3V, 5.4V instead of 6V, etc.). I'm interested in any tips you may have on how to debug this issue. Thanks! -- Xander Huff Staff Software Engineer National Instruments