diff --git a/Documentation/devicetree/bindings/memory-controllers/mediatek,smi-common.yaml b/Documentation/devicetree/bindings/memory-controllers/mediatek,smi-common.yaml
index 602592b6c3f54..3a82b0b27fa0a 100644
--- a/Documentation/devicetree/bindings/memory-controllers/mediatek,smi-common.yaml
+++ b/Documentation/devicetree/bindings/memory-controllers/mediatek,smi-common.yaml
@@ -38,6 +38,7 @@ properties:
           - mediatek,mt8192-smi-common
           - mediatek,mt8195-smi-common-vdo
           - mediatek,mt8195-smi-common-vpp
+          - mediatek,mt8195-smi-sub-common
 
       - description: for mt7623
         items:
@@ -67,6 +68,10 @@ properties:
     minItems: 2
     maxItems: 4
 
+  mediatek,smi:
+    $ref: /schemas/types.yaml#/definitions/phandle
+    description: a phandle to the smi-common node above. Only for sub-common.
+
 required:
   - compatible
   - reg
@@ -93,6 +98,29 @@ allOf:
             - const: smi
             - const: async
 
+  - if:  # only for sub common
+      properties:
+        compatible:
+          contains:
+            enum:
+              - mediatek,mt8195-smi-sub-common
+    then:
+      required:
+        - mediatek,smi
+      properties:
+        clock:
+          items:
+            minItems: 3
+            maxItems: 3
+        clock-names:
+          items:
+            - const: apb
+            - const: smi
+            - const: gals0
+    else:
+      properties:
+        mediatek,smi: false
+
   - if:  # for gen2 HW that have gals
       properties:
         compatible: