Re: [PATCH 1/2] i2c: qup: Cleared the error bits in ISR

[Abhishek Sahu]

On Thu, May 12, 2016 at 12:13:47AM -0500, Andy Gross wrote:
> On Wed, May 11, 2016 at 11:04:17PM +0530, Abhishek Sahu wrote:
> 
> <snip>
> 
> > >       In qup_i2c_xfer and qup_i2c_xfer_v2 state is set to RESET at the
> > >end, when
> > >       there is no error. So would it be fine if we do it there
> > >unconditionally ?
> > >
> > >Regards,
> > > Sricharan
> > 
> > RESET the QUP state wouldn't create any issue in the case of multiple calls.
> > The existing code also RESET the QUP state for bus_err but it is not
> > clearing
> > status bits.
> 
> It'd be better to not reset the QUP inside the ISR at all.  I think the better
> solution is making the reset occur in the xfer function.  So just clear the bits
> like you should in the isr, and defer reset till later.

This is a HW workaround for QUP where we need to RESET the core in
ISR. When interrupt is level triggerd, more than one interrupt may
fire in error cases and QUP will generate these interrupts after
completion of current interrupt. Thus we reset the core immediately
in the ISR to ward off the next interrupt.

-- 
Abhishek Sahu