[PATCH v6 07/20] dt-bindings: PCI: dwc: Apply generic schema for generic device only

[Serge Semin <Sergey.Semin@baikalelectronics.ru>]

Having the generic compatible strings constraints with the 'any'+'generic
string' semantic implicitly encourages either to add new DW PCIe-based
DT-bindings with the generic compatible string attached or just forget
about adding new DT-bindings since the corresponding DT-node will be
evaluated anyway. Moreover having that semantic implemented in the
generic DT-schema causes the DT-validation tool to apply the schema twice:
first by implicit compatible-string-based selection and second by means of
the 'allOf: [ $ref ]' statement. Let's fix all of that by dropping the
compatible property constraints and selecting the generic DT-schema only
for the purely generic DW PCIe DT-nodes. The later is required since there
is a driver for such devices. (Though there are no such DT-nodes currently
defined in the kernel DT sources.)

Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: Rob Herring <robh@kernel.org>

---

Changelog v3:
- This is a new patch unpinned from the next one:
  https://lore.kernel.org/linux-pci/20220503214638.1895-2-Sergey.Semin@baikalelectronics.ru/
  by the Rob' request. (@Rob)
- Fix compatible property schema so one would work as expected: string
  must contain either generic DW PCIe IP-core name or both generic and
  equipped with IP-core version names.

Changelog v5:
- Switch the patch from not-selecting the generic schemas to applying
  them to the generic DW PCIe device nodes only.
- Drop the generic compatible string used as fallback. (@Rob)
---
 .../devicetree/bindings/pci/snps,dw-pcie-ep.yaml | 16 ++++++++++------
 .../devicetree/bindings/pci/snps,dw-pcie.yaml    | 16 ++++++++++------
 2 files changed, 20 insertions(+), 12 deletions(-)

diff --git a/Documentation/devicetree/bindings/pci/snps,dw-pcie-ep.yaml b/Documentation/devicetree/bindings/pci/snps,dw-pcie-ep.yaml
index fc3b5d4ac245..d04001248b53 100644
--- a/Documentation/devicetree/bindings/pci/snps,dw-pcie-ep.yaml
+++ b/Documentation/devicetree/bindings/pci/snps,dw-pcie-ep.yaml
@@ -13,16 +13,20 @@ maintainers:
 description: |
   Synopsys DesignWare PCIe host controller endpoint
 
+# Please create a separate DT-schema for your DWC PCIe Endpoint controller
+# and make sure it's assigned with the vendor-specific compatible string.
+select:
+  properties:
+    compatible:
+      const: snps,dw-pcie-ep
+  required:
+    - compatible
+
 allOf:
   - $ref: /schemas/pci/pci-ep.yaml#
   - $ref: /schemas/pci/snps,dw-pcie-common.yaml#
 
 properties:
-  compatible:
-    anyOf:
-      - {}
-      - const: snps,dw-pcie-ep
-
   reg:
     description: |
       It should contain Data Bus Interface (dbi) and config registers for all
@@ -38,9 +42,9 @@ properties:
       enum: [dbi, dbi2, config, atu, addr_space, link, atu_dma, appl]
 
 required:
+  - compatible
   - reg
   - reg-names
-  - compatible
 
 additionalProperties: true
 
diff --git a/Documentation/devicetree/bindings/pci/snps,dw-pcie.yaml b/Documentation/devicetree/bindings/pci/snps,dw-pcie.yaml
index e787b9727589..85861b71d9ff 100644
--- a/Documentation/devicetree/bindings/pci/snps,dw-pcie.yaml
+++ b/Documentation/devicetree/bindings/pci/snps,dw-pcie.yaml
@@ -13,16 +13,20 @@ maintainers:
 description: |
   Synopsys DesignWare PCIe host controller
 
+# Please create a separate DT-schema for your DWC PCIe Root Port controller
+# and make sure it's assigned with the vendor-specific compatible string.
+select:
+  properties:
+    compatible:
+      const: snps,dw-pcie
+  required:
+    - compatible
+
 allOf:
   - $ref: /schemas/pci/pci-bus.yaml#
   - $ref: /schemas/pci/snps,dw-pcie-common.yaml#
 
 properties:
-  compatible:
-    anyOf:
-      - {}
-      - const: snps,dw-pcie
-
   reg:
     description: |
       It should contain Data Bus Interface (dbi) and config registers for all
@@ -47,9 +51,9 @@ properties:
 additionalProperties: true
 
 required:
+  - compatible
   - reg
   - reg-names
-  - compatible
 
 examples:
   - |
-- 
2.38.0