Re: [PATCH 2/4] i2c: omap: implement workaround for handling invalid BB-bit values

From: Wolfram Sang
Date: Sat Nov 22 2014 - 08:22:09 EST


On Fri, Nov 21, 2014 at 10:08:08AM -0600, Felipe Balbi wrote:
> On Fri, Nov 21, 2014 at 01:28:43AM +0400, Alexander Kochetkov wrote:
> > In a multimaster environment, after IP software reset, BB-bit value doesn't
> > correspond to the current bus state. It may happen what BB-bit will be 0,
> > while the bus is busy due to another I2C master activity.
> >
> > Any transfer started when BB=0 and bus is busy wouldn't be completed by IP
> > and results in controller timeout. More over, in some cases IP could
> > interrupt another master's transfer and corrupt data on wire.
> >
> > The commit implement method allowing to prevent IP from entering into
> > "controller timeout" state and from "data corruption" state.
> >
> > The one drawback is the need to wait for 10ms before the first transfer.
> >
> > Tested on Beagleboard XM C.
> >
> > Signed-off-by: Alexander Kochetkov <al.kochet@xxxxxxxxx>
>
> Tested on BBB and AM437x Starter Kit
>
> Tested-by: Felipe Balbi <balbi@xxxxxx>
> Reviewed-by: Felipe Balbi <balbi@xxxxxx>

Huh, I can't apply this one? Which kernel version is this based on?

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