From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kevin Hilman Subject: Re: [PATCH v2] I2C: OMAP: Recover from Bus Busy condition Date: Wed, 11 Jan 2012 14:28:20 -0800 Message-ID: <87vcoh27sr.fsf@ti.com> References: <1326303693-30106-1-git-send-email-shubhrajyoti@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: In-Reply-To: <1326303693-30106-1-git-send-email-shubhrajyoti-l0cyMroinI0@public.gmane.org> (Shubhrajyoti D.'s message of "Wed, 11 Jan 2012 23:11:33 +0530") Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Shubhrajyoti D Cc: linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-omap-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, ben-linux-elnMNo+KYs3YtjvyW6yDsg@public.gmane.org, Vikram Pandita , Jon Hunter List-Id: linux-i2c@vger.kernel.org Shubhrajyoti D writes: > From: Vikram Pandita > > In case a peripheral is driving SDA bus low (ie. a start condition), provide > a constant clock output using the test mode of the OMAP I2C controller to > try and clear the bus. Soft reset I2C controller after attempting the bus clear > to ensure that controller is in a good state. > > Based upon Vikram Pandita's patch from TI Android 3.0 kernel and modified for > mainline by Jon Hunter. > > A couple differences from the original patch ... > 1. Add a new function for bus clear > 2. Ensure that the CON.I2C_EN bit is set when using the SYSTEST feature to > output a permanent clock. This bit needs to be set and tpyically it would > be set by the unidle function but this is not the case for all OMAP > generations. > 3. Program the SYSTEST setting only the bits we care about. However, restore > SYSTEST registers to there original state as some OMAP generations do not > implement perform a soft-reset. > 4. Clear the CON register after performing the bus clear, so when we call the > init function the controller is disabled and the init function will > re-enable later. > > Cc: Kevin Hilman > Signed-off-by: Vikram Pandita > Signed-off-by: Jon Hunter > Signed-off-by: Shubhrajyoti D > --- > Original patch can be found here: > http://git.omapzoom.org/?p=kernel/omap.git;a=commit;h=a2ab04192ba25e60f95ba1ff3af5601a2d7b5bd1 > applies on Kevin's for_3.3/i2c/misc Please also explain how this was tested, and on what platforms. Thanks, Kevin From mboxrd@z Thu Jan 1 00:00:00 1970 From: khilman@ti.com (Kevin Hilman) Date: Wed, 11 Jan 2012 14:28:20 -0800 Subject: [PATCH v2] I2C: OMAP: Recover from Bus Busy condition In-Reply-To: <1326303693-30106-1-git-send-email-shubhrajyoti@ti.com> (Shubhrajyoti D.'s message of "Wed, 11 Jan 2012 23:11:33 +0530") References: <1326303693-30106-1-git-send-email-shubhrajyoti@ti.com> Message-ID: <87vcoh27sr.fsf@ti.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Shubhrajyoti D writes: > From: Vikram Pandita > > In case a peripheral is driving SDA bus low (ie. a start condition), provide > a constant clock output using the test mode of the OMAP I2C controller to > try and clear the bus. Soft reset I2C controller after attempting the bus clear > to ensure that controller is in a good state. > > Based upon Vikram Pandita's patch from TI Android 3.0 kernel and modified for > mainline by Jon Hunter. > > A couple differences from the original patch ... > 1. Add a new function for bus clear > 2. Ensure that the CON.I2C_EN bit is set when using the SYSTEST feature to > output a permanent clock. This bit needs to be set and tpyically it would > be set by the unidle function but this is not the case for all OMAP > generations. > 3. Program the SYSTEST setting only the bits we care about. However, restore > SYSTEST registers to there original state as some OMAP generations do not > implement perform a soft-reset. > 4. Clear the CON register after performing the bus clear, so when we call the > init function the controller is disabled and the init function will > re-enable later. > > Cc: Kevin Hilman > Signed-off-by: Vikram Pandita > Signed-off-by: Jon Hunter > Signed-off-by: Shubhrajyoti D > --- > Original patch can be found here: > http://git.omapzoom.org/?p=kernel/omap.git;a=commit;h=a2ab04192ba25e60f95ba1ff3af5601a2d7b5bd1 > applies on Kevin's for_3.3/i2c/misc Please also explain how this was tested, and on what platforms. Thanks, Kevin