Re: [PATCH v2 2/2] arm64: dts: qcom: kaanapali: fix traceNoC probe issue

[Jie Gan]

On 6/24/2026 11:16 PM, Leo Yan wrote:
> On Wed, Jun 24, 2026 at 11:08:32PM +0800, Jie Gan wrote:
>
> [...]
>
> > > Why does it fail ? power management ? hw broken ? Is it really AMBA or
> > > do you pretend that to be an AMBA device by faking the CID/PID?
> >
> > The CID reads as 0 from the register, which I suspect is a hardware design
> > issue. I have not yet confirmed this with the hardware team. As a
> > workaround, I provided a fake periphid via a DT property to bypass
> > amba_read_periphid.
> >
> >
> > Leo commented in other thread:
> > > > tnoc.c registers both an AMBA driver and a platform driver. Shouldn't >>it
> > > > be registered as a platform device instead?
> >
> > The platform driver is intended for the interconnect TraceNoC device and is
> > not designed to allocate an ATID. The issue is that the TPDM device borrows
> > the ATID from the TraceNoC device, resulting in the ATID always being 0 when
> > associated with an interconnect NoC device.
> >
> > However, I believe it is acceptable to allocate an ATID for the itNoC device
> > and the issue can be fixed with this way.
>
> I think so.

Hi Suzuki/Leo

Which solution do you prefer to address the issue?
The interconnect traceNoC platform driver is intended for the itnoc 
device, implying that no TPDM devices are connected to it. So, if I 
modify it to allocate an ATID, I think it would be better to rename the 
“itnoc” node accordingly? Or it's ok to leave it as-is?

BTW, the traceNoC device definitely is an AMBA device with CID/PID 
registers.

Thanks,
Jie