[PATCH v5 1/7] dt-bindings: display: verisilicon,dc: generalize for single-output variants

[Joey Lu <a0987203069@gmail.com>]

The verisilicon,dc binding was originally written for the T-Head TH1520
SoC carrying a DC8200, and hard-codes five clocks, three resets and two
output ports.

Add the Nuvoton MA35D1 DCUltraLite (nuvoton,ma35d1-dcu) to the binding.
The DCUltraLite uses only two clocks (core, pix0) and one reset (core),
with a single output port.

Use allOf/if blocks to express per-variant constraints rather than
hard-coding the DC8200 topology at the top level.  Each compatible's
block constrains the clock and reset item counts; the nuvoton block
additionally overrides clock-names to the two names it actually uses.

Signed-off-by: Joey Lu <a0987203069@gmail.com>
---
 .../bindings/display/verisilicon,dc.yaml      | 57 +++++++++++++++++++
 1 file changed, 57 insertions(+)

diff --git a/Documentation/devicetree/bindings/display/verisilicon,dc.yaml b/Documentation/devicetree/bindings/display/verisilicon,dc.yaml
index 9dc35ab973f2..1e751f3c7ce8 100644
--- a/Documentation/devicetree/bindings/display/verisilicon,dc.yaml
+++ b/Documentation/devicetree/bindings/display/verisilicon,dc.yaml
@@ -17,6 +17,7 @@ properties:
     items:
       - enum:
           - thead,th1520-dc8200
+          - nuvoton,ma35d1-dcu
       - const: verisilicon,dc # DC IPs have discoverable ID/revision registers
 
   reg:
@@ -77,6 +78,62 @@ required:
   - clock-names
   - ports
 
+allOf:
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: thead,th1520-dc8200
+    then:
+      properties:
+        clocks:
+          minItems: 5
+          maxItems: 5
+
+        clock-names:
+          minItems: 5
+          maxItems: 5
+
+        resets:
+          minItems: 3
+          maxItems: 3
+
+        reset-names:
+          minItems: 3
+          maxItems: 3
+
+      required:
+        - resets
+        - reset-names
+
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: nuvoton,ma35d1-dcu
+    then:
+      properties:
+        clocks:
+          minItems: 2
+          maxItems: 2
+
+        clock-names:
+          items:
+            - const: core
+            - const: pix0
+
+        resets:
+          minItems: 1
+          maxItems: 1
+
+        reset-names:
+          items:
+            - const: core
+
+      required:
+        - resets
+        - reset-names
+
 additionalProperties: false
 
 examples:
-- 
2.43.0