From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754079Ab3GBRPz (ORCPT ); Tue, 2 Jul 2013 13:15:55 -0400 Received: from mail.free-electrons.com ([94.23.35.102]:47463 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752550Ab3GBRPx (ORCPT ); Tue, 2 Jul 2013 13:15:53 -0400 Message-ID: <51D30AC5.9000701@free-electrons.com> Date: Tue, 02 Jul 2013 19:15:49 +0200 From: Alexandre Belloni Organization: Free Electrons User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130623 Thunderbird/17.0.7 MIME-Version: 1.0 To: Marek Vasut CC: Fabio Estevam , Shawn Guo , Jonathan Cameron , brian@crystalfontz.com, linux-doc@vger.kernel.org, linux-iio@vger.kernel.org, devicetree-discuss@lists.ozlabs.org, jimwall@q.com, Rob Herring , linux-kernel@vger.kernel.org, Grant Likely , Rob Landley , Maxime Ripard , linux-arm-kernel@lists.infradead.org, Lucas Stach Subject: Re: [PATCHv3 2/3] ARM: mxs: cfa10049: Switch bus i2c1 to bitbanging References: <1372094699-3832-1-git-send-email-alexandre.belloni@free-electrons.com> <51D2BEA1.6010206@free-electrons.com> <51D2DE5B.9060309@free-electrons.com> <201307021833.04282.marex@denx.de> In-Reply-To: <201307021833.04282.marex@denx.de> X-Enigmail-Version: 1.4.6 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/07/2013 18:33, Marek Vasut wrote: > Dear Alexandre Belloni, > >> On 02/07/2013 13:50, Alexandre Belloni wrote: >>> On 02/07/2013 13:45, Fabio Estevam wrote: >>>> Shouldn't this be >>>> >>>> i2c@1 { >>>> >>>> reg = <1>; ? >>> >>> No, we have 4 devices on that mux and 2 pins to select the muxing. >> >> OK, got it working. >> >> So, the results: >> >> bitbanging: >> >> # time cat /sys/bus/iio/devices/iio\:device1/in_voltage0_raw >> 2637 >> real 0m 0.09s >> user 0m 0.01s >> sys 0m 0.01s >> >> >> i2c-mxs PIO mode: >> >> # time cat /sys/bus/iio/devices/iio\:device1/in_voltage0_raw >> [ 35.007650] [sched_delayed] sched: RT throttling activated >> 2627 >> real 0m 7.14s >> user 0m 0.02s >> sys 0m 0.01s >> >> >> i2c-mxs PIO mode without LRADC: >> >> # time cat /sys/bus/iio/devices/iio\:device1/in_voltage0_raw >> [ 18.007432] [sched_delayed] sched: RT throttling activated >> 2629 >> real 0m 7.09s >> user 0m 0.00s >> sys 0m 0.03s >> >> >> i2c-mxs DMA mode: >> >> # time cat /sys/bus/iio/devices/iio\:device1/in_voltage0_raw >> 2631 >> real 0m 0.12s >> user 0m 0.01s >> sys 0m 0.01s >> >> >> It seems fine for me. > > I think I'm getting a little lost in these gazilions of i2c and lradc threads. > Can we not create one thread and keep the related stuff in there instead of > discussing it all around !? > > Only one question comes to mind with this email -- what do LRADC and I2C have to > do with each other here ? > Yeah, sorry, I meant the lradc touchscreen support. This seemed to trigger the issue for Fabio but as my testing shows, this is not the case for me, I get the issue with PIO, whether the lradc touchscreen support is activated or not. I think Torsten is the one that investigated it the most : http://www.spinics.net/lists/linux-i2c/msg12619.html > It'd be nice if someone could summarize on what I should focus and possibly > prepare a testcase. > On my setup, it happens on every i2c read that are done in PIO mode. But, my setup may be a bit unconventional as we are using a i2c gpio muxer. Regards, -- Alexandre Belloni, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com