Re: [PATCH v3 1/3] dt-bindings: i3c: xlnx: Add IBI and hot-join capability properties

[Patil, Shubham Sanjay]

Hi Frank,

On 10/21/2026 8:43 PM, Frank Li wrote:
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>
>
> On Wed, Oct 21, 2026 at 09:06:50AM +0200, Michal Simek wrote:
> > Hi Rob,
> >
> > On 10/7/26 08:03, Patil, Shubham Sanjay wrote:
> > > Hi Rob, Just a reminder !
> >
> > <snip>
> >
> > > > > > > > No reason to keep hj because the difference between HJ and IBI is the
> > > > > > > > address when address arbitration. If hardware support IBI, it should support
> > > > > > > > HJ. HJ just use special address 0x2.
> > > > > > >
> > > > > > > For this IP, they appear to be controlled by different configuration time
> > > > > > > parameters, so I don't think conflating the two is the right thing to do
> > > > > > > here:
> > > > > > > https://docs.amd.com/r/en-US/pg439-axi-i3c/Configuration-Tab
> > > > > > > Per this doc, and the original commit, hotjoin configuration is not
> > > > > > > permitted when ibi is not supported but can be enabled and disabled
> > > > > > > separately when it is.
> > > > > >
> > > > > > I am not sure why provide such flexiblity, only difference is that compare
> > > > > > address 2 or other value.
> > > > >
> > > > > It's not unusual for FPGA IPs to provide extreme flexibility so that the
> > > > > consumption of resources can be kept to a minimum, often to the point of
> > > > > excessiveness. E.g. for a ethernet MAC IP each individual statistic might
> > > > > have a configuration option.
> > > > >
> > > > > > This feature may be quite common for i3c, if other soft IP provider such
> > > > > > flexiblity, still common property is the better than vendor specific one.
> > > > >
> > > > > I'm not at all in favour of speculatively adding properties for
> > > > > configuration properties of FPGA IPs, particularly given the likelihood
> > > > > of abuse by others. Without multiple demonstrated users, things shouldn't
> > > > > be considered for being made common anyway.
> > > >
> > > > Rob:
> > > >           What's your opinion? I predict we will met similar problem when
> > > > I3C become popluar.
> > > >           Do you perfer use vendor property fistly or direct add common
> > > > property?
> > > >           There will be back compatible problem if change vendor property to
> > > > common property.
> > > >
> > > > Frank
> >
> > It looks like this thread is stuck and everybody is waiting for your opinion
> > about it. Can you please take a look when you have time?
>
> I suggest make a version, which support all enable/disable IBI/HJ. We can
> discuss later. I think less possible to config two difference instance at
> one SoC.
>
> Frank

My understanding is that the next version should support both enabling 
and disabling In-Band Interrupt, and both enabling and disabling Hot-Join.

For compatible "xlnx,axi-i3c-1.0", both features are enabled by default. 
A device-tree property is needed only to force a feature off on one 
controller instance. I will not use xlnx,in-band-interrupt-capable or 
xlnx,hot-join-capable. The case of two instances on one SoC with 
different synthesis options can be discussed later.

Please correct me if this is not what you meant.

Thanks,
Shubham

> > Thanks,
> > Michal