From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexander Sverdlin Subject: [PATCH 0/3] i2c: davinci: Fix problems discovered on Keystone CPU Date: Wed, 11 Mar 2015 14:08:48 +0100 Message-ID: <55003E60.3070306@nokia.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Wolfram Sang , Kevin Hilman , Sekhar Nori , Grygorii Strashko , Santosh Shilimkar , "Vishwanathrao Badarkhe, Manish" , Murali Karicheri Cc: Lawnick Michael 61283229 , Mike Looijmans , Mastalski Bartosz List-Id: linux-i2c@vger.kernel.org During intensive I2C tests on Keystone CPU we've discovered several problems with the i2c-davinci driver. Maybe Keystone is the first relatively powerful CPU utilizing davinci controller and therefore the races in the driver became more obvious, but it's clear that many users had problems with the driver and even though driver has received many band aids over the years, nobody addressed the original racy design. The series address the follwing problems: "i2c: davinci: Rework racy ISR" -- stop the parallel activities in the driver including concurrect registers access. Also simplifies the design and removes some bad aids. "i2c: davinci: Refactor i2c_davinci_wait_bus_not_busy()" -- the routine is over-designed and instead of "waiting" will trigger the bus recovering immediately. "i2c: davinci: Avoid sending to own address" -- works around one davinci controller issue when it unexpectedly switches to some sort of slave mode trying to send to its own address. The controller remains in this locked state until reset, so it's better to avoid this situation than to deal with transfer timeouts.