[PATCH 12/12] i2c: pxa: enable/disable i2c module across msg xfer

[yizhang@mx0b-0016f401.pphosted.com (Yi Zhang)]

On Tue, Jun 02, 2015 at 10:29:23PM +0530, Vaibhav Hiremath wrote:
> 
> 
> On Tuesday 02 June 2015 10:22 PM, Vaibhav Hiremath wrote:
> >
> >
> >On Thursday 28 May 2015 06:53 PM, Russell King - ARM Linux wrote:
> >>On Thu, May 28, 2015 at 06:33:44PM +0530, Vaibhav Hiremath wrote:
> >>>From: Yi Zhang <yizhang@marvell.com>
> >>>
> >>>Enable i2c module/unit before transmission and disable when it finishes.
> >>>
> >>>why?
> >>>It's because the i2c bus may be distrubed if the slave device,
> >>>typically a touch, powers on.
> >>
> >>"disturbed"
> >>
> >>I'd recommend that this is a DT property - not every platform is going to
> >>want this, and as there is rudimentary I2C slave support in this driver,
> >>this change breaks that.
> >>
> >
> >I would take it as two different comments here, and I believe you also
> >meant same,
> >
> >1. Not breaking I2C slave support
> >
> >Not sure whether enabling/disabling module in ISR would suffice here.
> >To be specific, in the functions i2c_pxa_slave_start() &
> >i2c_pxa_slave_stop()
> >
> >
> 
> Please ignore this option, as enable is important to generate interrupt
> on slave start.
  
  Yes, you are right, enabling i2c controller first is must for
  generating the interrupt
> 
> I will add DT property with clear note on SLAVE support issue, so that
> it can be disabled and SLAVE support should work as is.
> 
> Thanks,
> Vaibhav