Re: [PATCH 1/2] dt-bindings: misc: introduce pci1179,0220.yaml

On 14/08/2026 18:55, Alex Elder wrote:
> On 8/14/26 2:01 AM, Krzysztof Kozlowski wrote:
>> On Thu, Aug 13, 2026 at 05:29:41PM -0500, Alex Elder wrote:
>>> Define the binding for the Toshiba TC9564 PCI endpoint function device.
>>> The third downstream PCIe switch port within this chip has an embedded
>>> PCIe controller, and that implements two of these PCIe functions.
>>>
>>> Signed-off-by: Daniel Thompson <[email protected]>
>>> Signed-off-by: Alex Elder <[email protected]>
>>> ---
>>>   .../bindings/misc/pci1179,0220.yaml           | 150 ++++++++++++++++++
>>>   MAINTAINERS                                   |   6 +
>>>   2 files changed, 156 insertions(+)
>>>   create mode 100644 Documentation/devicetree/bindings/misc/pci1179,0220.yaml
>>>
>>
>> There are no properties in the binding except standard PCIe ones, so why
>> do you need it in DT in the first place? We do not describe PCI devices
>> in DT by default, so you are doing something unusual. Commit msg should
>> explain that.
> 
> Maybe because it's using pci-ep-bus?  I'm not sure I can answer your
> question though.

What is pcie-ep bus? If a device is a PCI device (so not the host
bridge), we do not need to define it in DT except a few cases and this
does not look like one.

> 
> An earlier version used auxiliary devices.  This time the PCI device
> sort of stands by itself as provider of the endpoint buses that are
> used by other devices within the SoC.  There is otherwise no single
> driver (e.g., for an Ethernet interface) that is implemented as a
> PCI driver to bind with the hardware.  The SoC drivers will all be
> platform drivers.

All this is driver explanation, so does not really answer my questions.
Whether something is using platform bus or auxiliary devices it
absolutely does not matter for the DT. It cannot even matter for DT.

Best regards,
Krzysztof