From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.aswsp.com ([193.34.35.150]:30869 "EHLO mail.aswsp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751310AbcBOQNe (ORCPT ); Mon, 15 Feb 2016 11:13:34 -0500 Message-ID: <56C1F92D.2020506@parrot.com> Date: Mon, 15 Feb 2016 17:13:33 +0100 From: Gregor Boirie MIME-Version: 1.0 To: , Subject: libiio and unindexed channel Content-Type: text/plain; charset="utf-8"; format=flowed Sender: linux-iio-owner@vger.kernel.org List-Id: linux-iio@vger.kernel.org Hi all, I hope it is the right place to post for libiio related problems. Please, forgive my mistakeif it is not. I'm facing a rather odd problem with unindexed channel (as declared in ms5611 pressure driver iio_chan_spec 's). libiio does not consider pressure and temperature channels exposed by the driver as... channels. Trying to figure out why, I looked into libiio local backend and found that: * on tag v0.6, libiio simply consider unindexed driver channels as device attribute (see local.c:942) ; * on actual master, libiio will promote unindexed driver channels to channels BUT without the scan_element ability (see local.c:1130) I don't fully understand what real difference it makes but libiio manual says: a channel that is a scan element is a channel that can generate samples (for an input channel) or receive samples (for an output channel) after being enabled. I feel a bit lost here : I thought input channels were always able to generate samples. What is this iio_channel_is_scan_element() here for ? From userspace point of view, what channel indices should be used for ? Many thanks in advancefor sharing your time and knowledge. Regards, Gregor. P.S.: by the way, setting the "indexed" field of iio_chan_spec's in ms5611_core.c makes libiio see temperature and pressure as channels.