Re: [PATCHv11 6/6] i2c: omap: Recover from Bus Busy condition

[Wolfram Sang <w.sang-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>]

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On Thu, Jun 28, 2012 at 08:41:32PM +0530, Shubhrajyoti D wrote:
> From: Vikram Pandita <vikram.pandita-l0cyMroinI0@public.gmane.org>
> 
> 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.
> I acknowledge the contributions and suggestions of Jon and Hemant.
> 
> 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 typically 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.
> 
> Original patch can be found here:
> http://git.omapzoom.org/?p=kernel/omap.git;a=commit;h=a2ab04192ba25e60f95ba1ff3af5601a2d7b5bd1
> 
> Signed-off-by: Vikram Pandita <vikram.pandita-l0cyMroinI0@public.gmane.org>
> Signed-off-by: Jon Hunter <jon-hunter-l0cyMroinI0@public.gmane.org>
> Signed-off-by: Shubhrajyoti D <shubhrajyoti-l0cyMroinI0@public.gmane.org>

This has to wait a little bit until I can spend time on the recovery
framework (which is still in the queue, sadly :( ). There might be some
consolidation.

-- 
Pengutronix e.K.                           | Wolfram Sang                |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |

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