Some of the SMI Common HW provides access control to at least
the power controller: document the #access-controller-cells
property and allow specifying it only for MT8183 and MT8365
as those are the only known SoCs with an SMI acting as access
controller.

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
---
 .../memory-controllers/mediatek,smi-common.yaml  | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/Documentation/devicetree/bindings/memory-controllers/mediatek,smi-common.yaml b/Documentation/devicetree/bindings/memory-controllers/mediatek,smi-common.yaml
index 0762e0ff66ef..74b355a08493 100644
--- a/Documentation/devicetree/bindings/memory-controllers/mediatek,smi-common.yaml
+++ b/Documentation/devicetree/bindings/memory-controllers/mediatek,smi-common.yaml
@@ -74,6 +74,9 @@ properties:
     minItems: 2
     maxItems: 4
 
+  '#access-controller-cells':
+    const: 0
+
   mediatek,smi:
     $ref: /schemas/types.yaml#/definitions/phandle
     description: a phandle to the smi-common node above. Only for sub-common.
@@ -168,6 +171,19 @@ allOf:
             - const: apb
             - const: smi
 
+  - if:  # for SMI providing access control
+      properties:
+        compatible:
+          enum:
+            - mediatek,mt8183-smi-common
+            - mediatek,mt8365-smi-common
+    then:
+      properties:
+        '#access-controller-cells': true
+    else:
+      properties:
+        '#access-controller-cells': false
+
 additionalProperties: false
 
 examples:
-- 
2.49.0