[v12,1/2] i2c: buses: add i2c bus driver for NVIDIA GPU

[Wolfram Sang <wsa@the-dreams.de>]

On Mon, Oct 01, 2018 at 07:33:02PM +0000, Ajay Gupta wrote:
> Hi Heikki and Peter,
> 
> > > > > Can we get the working set in while the issues is being debugged?
> > > >
> > > > I'm not the one making the decision, and I don't even know if this
> > > > is going through the i2c or the usb tree? If it's going through the
> > > > i2c tree you need a tag from the usb people (Greg?) on patch 2/2,
> > > > and if it's going through the usb tree, you need a tag from Wolfram
> > > > on patch 1/2. As I said, I'm not involved with that part, I'm just
> > > > reviewing these patches because I felt like it.
> > > >
> > > > The remaining issue that bothers me is the looping reads, and your
> > > > email address reveals that you should be in a very good position to
> > > > work out why they do not work, and fix it or let us know why they
> > > > don't.
> > I am working with different teams to debug this and I think it may take some
> > time to know the root cause.
> We got confirmation from HW team about 4 byte read limitation. There has to
> be a STOP after every single read cycle. One read cycle supports maximum of
> 4 byte burst. I will update the patches with a comment on this.

Could it be that this is more an SMBus controller than an I2C
controller? I haven't looked at the specs but maybe populating
smbus_xfer instead of master_xfer is an option here?