Re: [PATCH] dt-bindings: pci: brcmstb: Add rp1-nexus node to fix DTC warning

Hi Krzysztof,

On 10:55 Tue 12 Aug     , Krzysztof Kozlowski wrote:

On 12/08/2025 10:50, Andrea della Porta wrote:

quoted

The devicetree compiler is complaining as follows:

arch/arm64/boot/dts/broadcom/rp1-nexus.dtsi:3.11-14.3: Warning (unit_address_vs_reg): /axi/pcie@1000120000/rp1_nexus: node has a reg or ranges property, but no unit name
/home/andrea/linux-torvalds/arch/arm64/boot/dts/broadcom/bcm2712-rpi-5-b.dtb: pcie@1000120000: Unevaluated properties are not allowed ('rp1_nexus' was unexpected)

Please trim the paths.

Ack.

quoted

Add the optional node that fix this to the DT binding.

Reported-by: kernel test robot <redacted>
Closes: https://lore.kernel.org/oe-kbuild-all/202506041952.baJDYBT4-lkp@intel.com/ (local)
Signed-off-by: Andrea della Porta <andrea.porta@suse.com>
---
 Documentation/devicetree/bindings/pci/brcm,stb-pcie.yaml | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/Documentation/devicetree/bindings/pci/brcm,stb-pcie.yaml b/Documentation/devicetree/bindings/pci/brcm,stb-pcie.yaml
index 812ef5957cfc..7d8ba920b652 100644
--- a/Documentation/devicetree/bindings/pci/brcm,stb-pcie.yaml
+++ b/Documentation/devicetree/bindings/pci/brcm,stb-pcie.yaml

@@ -126,6 +126,15 @@ required:
 allOf:
   - $ref: /schemas/pci/pci-host-bridge.yaml#
   - $ref: /schemas/interrupt-controller/msi-controller.yaml#
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: brcm,bcm2712-pcie
+    then:
+      properties:
+        rp1_nexus:

No, you cannot document post-factum... This does not follow DTS coding
style.

I think I didn't catch what you mean here: would that mean that
we cannot resolve that warning since we cannot add anything to the
binding?

Regarding rp1_nexus, you're right I guess it should be
rp1-nexus as per DTS coding style.

Also:

Node names should be generic. See also an explanation and list of
examples (not exhaustive) in DT specification:
https://devicetree-specification.readthedocs.io/en/latest/chapter2-devicetree-basics.html#generic-names-recommendation

In this case it could be difficult: we need to search for a DT node
starting from the DT root and using generic names like pci@0,0 or
dev@0,0 could possibly led to conflicts with other peripherals.
That's why I chose a specific name.

Many thanks,
Andrea

... and nodes should be anyway defined in top-level and only customized
per variant. I am surprised that DTS patch carries a reviewed tag,
because it was never checked/tested :/

quoted

+          $ref: /schemas/misc/pci1de4,1.yaml
   - if:
       properties:
         compatible:

Best regards,
Krzysztof