dt-bindings: riscv: add vector sub-extension dependencies

Section 33.18.2. Zve*: Vector Extensions for Embedded Processors
in [1] says:
| The Zve32f and Zve64x extensions depend on the Zve32x extension. The Zve64f extension depends
| on the Zve32f and Zve64x extensions. The Zve64d extension depends on the Zve64f extension

| The Zve32x extension depends on the Zicsr extension. The Zve32f and Zve64f extensions depend
| upon the F extension

| The Zve64d extension depends upon the D extension

Apply these rules to the bindings to help prevent invalid combinations.

Link: https://github.com/riscv/riscv-isa-manual/releases/tag/riscv-isa-release-698e64a-2024-09-09 [1]
Reviewed-by: Clément Léger <cleger@rivosinc.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20250312-banking-crestless-58f3259a5018@spud
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>

1 files changed, 46 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/riscv/extensions.yaml b/Documentation/devicetree/bindings/riscv/extensions.yaml
index ebb252275ddd..02065664f819 100644
--- a/Documentation/devicetree/bindings/riscv/extensions.yaml
+++ b/Documentation/devicetree/bindings/riscv/extensions.yaml
@@ -680,6 +680,52 @@ properties:
           contains:
             const: zca
 
+      - if:
+          contains:
+            const: zve32x
+        then:
+          contains:
+            const: zicsr
+
+      - if:
+          contains:
+            const: zve32f
+        then:
+          allOf:
+            - contains:
+                const: f
+            - contains:
+                const: zve32x
+
+      - if:
+          contains:
+            const: zve64x
+        then:
+          contains:
+            const: zve32x
+
+      - if:
+          contains:
+            const: zve64f
+        then:
+          allOf:
+            - contains:
+                const: f
+            - contains:
+                const: zve32f
+            - contains:
+                const: zve64x
+
+      - if:
+          contains:
+            const: zve64d
+        then:
+          allOf:
+            - contains:
+                const: d
+            - contains:
+                const: zve64f
+
 allOf:
   # Zcf extension does not exist on rv64
   - if: