From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexandre Belloni Subject: Re: i2c-mxs woes Date: Fri, 19 Apr 2013 14:07:13 +0200 Message-ID: <51713371.6030805@free-electrons.com> References: <51712C8B.7070302@free-electrons.com> <1366372407.4146.3.camel@weser.hi.pengutronix.de> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1366372407.4146.3.camel-WzVe3FnzCwFR6QfukMTsflXZhhPuCNm+@public.gmane.org> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Lucas Stach Cc: linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, wsa-z923LK4zBo2bacvFa/9K2g@public.gmane.org, Marek Vasut , Maxime Ripard List-Id: linux-i2c@vger.kernel.org Hi Lucas, On 19/04/2013 13:53, Lucas Stach wrote: > Hi Alexandre, > > Am Freitag, den 19.04.2013, 13:37 +0200 schrieb Alexandre Belloni: >> Hi, >> >> I'm having some issues with the i2c-mxs driver in 3.9. Marek already >> pointed me to the patches from Lucas and that greatly improved the >> situation. >> >> For the context, my board has three nau7802 adcs, connected to a gpio >> i2c-muxer, connected to i2c1. >> >> Here is what I observe: >> >> On 3.9: >> >> # time cat /sys/bus/iio/devices/iio:device1/in_voltage0_raw >> 2620 >> real 0m 7.08s >> user 0m 0.00s >> sys 0m 0.02s >> # time cat /sys/bus/iio/devices/iio:device1/in_voltage1_raw >> 2623 >> real 0m 6.07s >> user 0m 0.01s >> sys 0m 0.01s >> # >> > Is this with or without my patches? Before introduction of the error > handling in PIO code there were a lot of situations where the controller > would signal an error, but the driver would go on as usual, so the next > transaction wouldn't succeed and stop for a whole second until the > timeout hits and resets the controller. This is with v2 of your patches. I applied "i2c-mxs remove races in PIO code" and "i2c-mxs do error checking and handling in PIO mode" Regards, -- Alexandre Belloni, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com