Re: [PATCH v4 1/5] dt-bindings: arm: coresight-tnoc: Add standalone qcom,coresight-agtnoc compatible

[Jie Gan]

On 7/1/2026 3:26 PM, Krzysztof Kozlowski wrote:
> On 01/07/2026 09:16, Jie Gan wrote:
> > On 7/1/2026 2:57 PM, Krzysztof Kozlowski wrote:
> > > On Wed, Jul 01, 2026 at 09:53:41AM +0800, Jie Gan wrote:
> > > > The TNOC compatible previously only allowed the two-string AMBA form
> > > > "qcom,coresight-tnoc", "arm,primecell", which forces the device onto the
> > > > AMBA bus.
> > > >
> > > > Convert the compatible to a oneOf and add a standalone
> > > > "qcom,coresight-agtnoc" compatible alongside the existing AMBA form. The
> > > > standalone string carries no "arm,primecell" entry, so the device is
> > > > created on the platform bus instead of the AMBA bus.
> > >
> > > That's a Linux driver specific reason, so not a valid one.
> > >
> > > Describe the hardware instead.
> > >
> > > Also, you do not get other compatible for the same device.
> >
> > The device is intended to be discovered and probed via the AMBA bus.
> > However, due to a hardware issue, AMBA probing does not work correctly.
> > While adding the arm,primecell-periphid property would allow the
>
> If this is not AMBA bus device, then drop primecell compatible.

Will drop the primecell compatible and update the description.

> > existing AMBA driver to bind, but I think that's a temp WA. As
> > Suzuki/Leo pointed out, we should not add the property to pretend the
> > device as an AMBA device.
> >
> > Instead, I introduced a dedicated compatible string so the device can be
> > handled by the existing platform driver without relying on the missing
>
> As I said, that's a Linux driver specific reason, so not a valid one.
>
> Fix your drivers if you insist on that.
>
> > AMBA primecell identification. The purpose of the new compatible is to
> > clearly distinguish this platform-specific case from the standard
> > AMBA-based implementation. Or shall I re-use the existing compatible
> > "qcom,coresight-tnoc" as platform standalone compatible?
> >
> > We already have a similar pattern for the interconnect TraceNoC device,
> > which uses the platform-specific compatible string qcom,coresight-itnoc.
> I do not see there a fake, duplicated compatible for the same device.
> Can you elaborate how is that relevant?

Will fix it by removing AMBA related description.

Shall I update the clock name from apb_pclk to apb as a platform device?

Thanks,
Jie

> Best regards,
> Krzysztof