Re: [PATCH RFC 1/2] dt-bindings: regmap: add common schema for no-sequential-read

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

On Thu, Jul 23, 2026 at 08:55:18PM +0200, Richard Leitner wrote:
> On Thu, Jul 23, 2026 at 07:10:48PM +0300, Laurent Pinchart wrote:
> > On Thu, Jul 23, 2026 at 05:02:42PM +0100, Conor Dooley wrote:
> > > On Thu, Jul 23, 2026 at 06:45:41PM +0300, Laurent Pinchart wrote:
> > > > On Thu, Jul 23, 2026 at 01:01:11PM +0200, Richard Leitner wrote:
> > > > > On Wed, Jul 22, 2026 at 11:03:09PM +0100, Mark Brown wrote:
> > > > > > On Wed, Jul 22, 2026 at 11:58:46PM +0200, Richard Leitner wrote:
> > > > > > 
> > > > > > > @Mark: I understood that if the fpga really intercepts the I2C bus, it
> > > > > > > should be modelled accordingly in device tree. But what would be the
> > > > > > > preferred implementation if both devices sit on the same I2C bus, but
> > > > > > > one is messing up some register reads on purpose?
> > > > > > 
> > > > > > I think we would need to have a coherent understanding and description
> > > > > > of the actual issue to know how to describe it.
> > > > > 
> > > > > Understood. I will try to figure out how the hardware is really wired
> > > > > and come back to you.
> > > > 
> > > > Based on the information I have received so far, the FPGA is interposed
> > > > between the host and sensor. It could therefore be modelled in DT as
> > > > child of the I2C bus and a parent of the sensor.
> > > > 
> > > > New version of some of the Vision Components modules have fixed the
> > > > multi-read bug, so we will still need a property in the FPGA DT node to
> > > > indicate if the quirk should be activated.
> > > 
> > > Or come up with a compatible for the FPGA DT node that uniquely
> > > identifies the revision of the RTL in use.
> > > That's my preference for things that use some custom RTL that aren't
> > > configuration parameters.
> > 
> > I'm afraid we won't be able to get that information. We have limited
> > visibility on the ecosystem of modules and what the FPGA does in each of
> > them.
> 
> Thanks for the clarification. Should I continue working on this topic
> (i.e. modelling the FPGA as I2C controller with the sensor as a
> "subdevice")? Or do you want to take over Laurent? Do you have any other
> downstream work on the vc-mipi stuff, except the patches in your gitlab
> repo?

I'm afraid I won't have time for the time being, as I will soon start my
summer holidays. The patches in the git tree you mentioned are all I
have.

> I've additionally wrote "my Vision Components contact" an email asking
> for clarification of the I2C bus layout on the modules yesterday. If I
> get any new information from that path I will of course take it into account.
> 
> Thanks a lot, Laurent!

-- 
Regards,

Laurent Pinchart