From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ppsw-51.csi.cam.ac.uk ([131.111.8.151]:52363 "EHLO ppsw-51.csi.cam.ac.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754988Ab1HWNds (ORCPT ); Tue, 23 Aug 2011 09:33:48 -0400 Message-ID: <4E53AE25.4040609@cam.ac.uk> Date: Tue, 23 Aug 2011 14:41:57 +0100 From: Jonathan Cameron MIME-Version: 1.0 To: malas CC: "Hennerich, Michael" , linux-iio@vger.kernel.org Subject: Re: ad7793 iio-ring test read issue - Reg References: <20110823080829.M36921@tcoe.iitm.ac.in> <4E538D35.7090508@cam.ac.uk> <20110823112234.M44553@tcoe.iitm.ac.in> <544AC56F16B56944AEC3BD4E3D59177146E6D069A2@LIMKCMBX1.ad.analog.com> <20110823121352.M43006@tcoe.iitm.ac.in> <4E539F70.3060209@cam.ac.uk> <20110823123747.M17135@tcoe.iitm.ac.in> <4E53A3FA.7020700@cam.ac.uk> <20110823131000.M76209@tcoe.iitm.ac.in> In-Reply-To: <20110823131000.M76209@tcoe.iitm.ac.in> Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-iio-owner@vger.kernel.org List-Id: linux-iio@vger.kernel.org On 08/23/11 14:24, malas wrote: > On Tue, 23 Aug 2011 13:58:34 +0100, Jonathan Cameron wrote >> On 08/23/11 13:43, malas wrote: >>> YES : Gregs updated kernel taken from link below: >>> >>> http://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging-2.6.git >> Right now that's pretty much mainline. >> >> See comments below and please reply inline as it makes this sort >> of discussion much easier to follow. >>> >>> >>> On Tue, 23 Aug 2011 13:39:12 +0100, Jonathan Cameron wrote >>>> On 08/23/11 13:17, malas wrote: >>>>> >>>>> >>>>> Sorry, I did not explicitly mention that. I did use the new staging kernel referred by >>>>> Michael Hennerich and integrated with 2010RC5 uclinux dist . >>>> >>>> Hmm. As in current contents of Greg KH's staging/staging-next? >>>> >>>> I'll assume so... See below. >>>> >>>>> >>>>> On Tue, 23 Aug 2011 12:39:53 +0100, Hennerich, Michael wrote >>>>>> malas wrote on 2011-08-23: >>>>>>> >>>>>>> >>>>>>> Dear Jonathan Cameron, >>>>>>> >>>>>>> The kernel version I am using is : >>>>>> >>>>>> Didn't you say that you use the staging kernel? >>>>>> >>>>>> >>>>> >>> > http://blackfin.uclinux.org/gf/project/uclinux-dist/forum/?_forum_action=MessageReply&message_id=102839&action=ForumBrowse >>>>>> >>>>>> Or copied drivers/staging/iio over to your Blackfin kernel tree? >>>>>> >>>>>>> >>>>>>> --------------------------------------------------------------------- >>>>>>> midas@ubuntu:~/Mala/Telemedicine/uclinux_source/uc2010_source/uclinux/2 >>>>>>> 010R1$ svn info Path: . URL: >>>>>>> svn://blackfin.uclinux.org/uclinux-dist/branches/2010R1 Repository Root: >>>>>>> svn://blackfin.uclinux.org/uclinux-dist Repository UUID: >>>>>>> 3e2a5524-39e8-4cb9-84a9-c49da69cba3a Revision: 10161 Node Kind: >>>>>>> directory Schedule: normal Last Changed Author: vapier Last Changed Rev: >>>>>>> 10136 Last Changed Date: 2011-04-02 22:36:15 +0530 (Sat, 02 Apr 2011) >>>>>>> --------------------------------------------------------------------- >>>>>>> >>>>>>> Regards >>>>>>> Mala >>>>>>> >>>>>>> On Tue, 23 Aug 2011 12:21:25 +0100, Jonathan Cameron wrote >>>>>>>> On 08/23/11 09:18, malas wrote: >>>>>>>>> >>>>>>>>> Dear Michael Hennerich, >>>>>>>>> >>>>>>>>> >>>>>>>>> I shall post iio quesris in this mail list as per your suggestions. >>>>>>>>> >>>>>>>>> AD7793 driver is built into kernel. The chip gets configured and am >>>>>>>>> able to read data on continuous mode via spi interface using ad7793 >>>>>>>>> driver at kernel level. >>>>>>>>> >>>>>>>>> While testing userspace test iio-ring to read data from ring buffer, >>>>>>>>> generic_buffer code was executed, it proceeds till opening >>>>>>>>> /sys/bus/iio/devices/device0:buffer0 and Read call fails. >>>>>>>> Question 1: What's the kernel and where did you get it from? >>>>>>>> (Interfaces are moving fast so it's plausible you've fallen in a hole >>>>>>>> where userspace wasn't matching kernelspace). >>>>>>>>> >>>>>>>>> In fs I can list the iio device ad7793 with following properties >>>>>>>>> get/set. >>>>>>>>> >>>>>>>>> root:/> ls /sys/bus/iio/devices/device0\:buffer0/ >>>>>>>>> bytes_per_datum enable power subsystem >>>>>>>>> dev length scan_elements uevent >>>>>>>>> root:/> >>>>>>>>> >>>>>>>>> I find access0 and event0 missing in this list. Is that the reason >>>>>>> for read() fails. >>>>>>>> Yes. Question is why and without kernel version I don't know where to >>>>>>>> look I'm afraid. >>>> Ah, this does look like a missmatch in interfaces between userspace and kernel. >>>> >>>> At this point in time we have scrapped the event0 chrdev (done via polling on >>>> the access one) and the access one has be flattened into device0\:buffer0/ >>>> (read dev). >>>> >>>> Looks like the generic_buffer.c example does line up though. Where did the >>>> 'test iio-ring' come from? Is that one yours Michael? > > > iio-ring.c under uclinux2010/user/blkfin-test/iio-ring-test. The file is in the > attached. I did not use that since i didn't find access0 or event0 files under > /sys/bus/iio/devices/device0:buffer0. > > I have tested with the generic_buffer.c example (under iio/documentaion folder) to get > Ad7793 received samples to user space from ring buffer. > The app opens: /dev/device0:buffer0 for poll and reading samples. > Is the device name for the open() correct. Yes - that should be right.