From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ppsw-50.csi.cam.ac.uk ([131.111.8.150]:43706 "EHLO ppsw-50.csi.cam.ac.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754966Ab1HWN7M (ORCPT ); Tue, 23 Aug 2011 09:59:12 -0400 Message-ID: <4E53B41A.4030309@cam.ac.uk> Date: Tue, 23 Aug 2011 15:07:22 +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> <4E53AE25.4040609@cam.ac.uk> <20110823134517.M58041@tcoe.iitm.ac.in> In-Reply-To: <20110823134517.M58041@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 14:48, malas wrote: > On Tue, 23 Aug 2011 14:41:57 +0100, Jonathan Cameron wrote >> 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. > ************************* > Open fails for "/dev/device0:buffer0" device name > I tried changing to "/sys/bus/iio/devices/device0:buffer0"- open() succeeded then but > then read fails. Read must be the one under dev. The other is a directory with description of the buffer. What is the error on the open of /dev/device0:buffer0?