[PATCH v3 1/5] dt-bindings: display: verisilicon,dc: generalize for single-output variants

[Joey Lu]

The existing schema hard-codes the five-clock/three-reset/dual-port
topology of the DC8200 IP block, preventing reuse for single-output
variants such as the Verisilicon DCUltraLite used in the Nuvoton MA35D1
SoC.

Rework the schema so that variant-specific constraints are expressed via
allOf/if blocks:

- Add nuvoton,ma35d1-dcu to the SoC-specific compatible enum.  The
  generic verisilicon,dc fallback remains the driver-binding string.
- Relax the top-level clocks/resets definitions to minItems ranges so
  the base schema accepts both variants.
- Keep ports in the global required list and keep additionalProperties
  tightened to unevaluatedProperties.
- Add an allOf/if block for thead,th1520-dc8200: five-clock (core, axi,
  ahb, pix0, pix1), three-reset (core, axi, ahb).
- Add an allOf/if block for nuvoton,ma35d1-dcu: two-clock (core, pix0),
  one-reset (core).
- Fix a stray space in the port at 0 description.
- Add a DT example for the Nuvoton MA35D1 DCU Lite using ports/port at 0.

Signed-off-by: Joey Lu <a0987203069 at gmail.com>
---
 .../bindings/display/verisilicon,dc.yaml      | 103 +++++++++++++++---
 1 file changed, 90 insertions(+), 13 deletions(-)

diff --git a/Documentation/devicetree/bindings/display/verisilicon,dc.yaml b/Documentation/devicetree/bindings/display/verisilicon,dc.yaml
index 9dc35ab973f2..db0260d874c5 100644
--- a/Documentation/devicetree/bindings/display/verisilicon,dc.yaml
+++ b/Documentation/devicetree/bindings/display/verisilicon,dc.yaml
@@ -17,7 +17,8 @@ properties:
     items:
       - enum:
           - thead,th1520-dc8200
-      - const: verisilicon,dc # DC IPs have discoverable ID/revision registers
+          - nuvoton,ma35d1-dcu
+      - const: verisilicon,dc  # DC IPs have discoverable ID/revision registers
 
   reg:
     maxItems: 1
@@ -26,6 +27,7 @@ properties:
     maxItems: 1
 
   clocks:
+    minItems: 2
     items:
       - description: DC Core clock
       - description: DMA AXI bus clock
@@ -34,24 +36,19 @@ properties:
       - description: Pixel clock of output 1
 
   clock-names:
-    items:
-      - const: core
-      - const: axi
-      - const: ahb
-      - const: pix0
-      - const: pix1
+    minItems: 2
+    maxItems: 5
 
   resets:
+    minItems: 1
     items:
       - description: DC Core reset
       - description: DMA AXI bus reset
       - description: Configuration AHB bus reset
 
   reset-names:
-    items:
-      - const: core
-      - const: axi
-      - const: ahb
+    minItems: 1
+    maxItems: 3
 
   ports:
     $ref: /schemas/graph.yaml#/properties/ports
@@ -59,7 +56,7 @@ properties:
     properties:
       port at 0:
         $ref: /schemas/graph.yaml#/properties/port
-        description: The first output channel , endpoint 0 should be
+        description: The first output channel, endpoint 0 should be
           used for DPI format output and endpoint 1 should be used
           for DP format output.
 
@@ -77,7 +74,60 @@ required:
   - clock-names
   - ports
 
-additionalProperties: false
+allOf:
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: thead,th1520-dc8200
+    then:
+      properties:
+        clocks:
+          minItems: 5
+          maxItems: 5
+
+        clock-names:
+          items:
+            - const: core
+            - const: axi
+            - const: ahb
+            - const: pix0
+            - const: pix1
+
+        resets:
+          minItems: 3
+          maxItems: 3
+
+        reset-names:
+          items:
+            - const: core
+            - const: axi
+            - const: ahb
+
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: nuvoton,ma35d1-dcu
+    then:
+      properties:
+        clocks:
+          minItems: 2
+          maxItems: 2
+
+        clock-names:
+          items:
+            - const: core
+            - const: pix0
+
+        resets:
+          maxItems: 1
+
+        reset-names:
+          items:
+            - const: core
+
+unevaluatedProperties: false
 
 examples:
   - |
@@ -120,3 +170,30 @@ examples:
         };
       };
     };
+
+  - |
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    #include <dt-bindings/clock/nuvoton,ma35d1-clk.h>
+    #include <dt-bindings/reset/nuvoton,ma35d1-reset.h>
+
+    display at 40260000 {
+        compatible = "nuvoton,ma35d1-dcu", "verisilicon,dc";
+        reg = <0x40260000 0x20000>;
+        interrupts = <GIC_SPI 20 IRQ_TYPE_LEVEL_HIGH>;
+        clocks = <&clk DCU_GATE>, <&clk DCUP_DIV>;
+        clock-names = "core", "pix0";
+        resets = <&sys MA35D1_RESET_DISP>;
+        reset-names = "core";
+
+        ports {
+            #address-cells = <1>;
+            #size-cells = <0>;
+
+            port at 0 {
+                reg = <0>;
+                dpi_out: endpoint {
+                    remote-endpoint = <&panel_in>;
+                };
+            };
+        };
+    };
-- 
2.43.0