[PATCH v9 2/3] dt-bindings: arm: mediatek: mmsys: Add OF graph support for board path

[AngeloGioacchino Del Regno]

Document OF graph on MMSYS/VDOSYS: this supports up to three DDP paths
per HW instance (so potentially up to six displays for multi-vdo SoCs).

The MMSYS or VDOSYS is always the first component in the DDP pipeline,
so it only supports an output port with multiple endpoints - where each
endpoint defines the starting point for one of the (currently three)
possible hardware paths.

Reviewed-by: Rob Herring (Arm) <robh at kernel.org>
Reviewed-by: Alexandre Mergnat <amergnat at baylibre.com>
Tested-by: Alexandre Mergnat <amergnat at baylibre.com>
Reviewed-by: CK Hu <ck.hu at mediatek.com>
Tested-by: Michael Walle <mwalle at kernel.org> # on kontron-sbc-i1200
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno at collabora.com>
---
 .../bindings/arm/mediatek/mediatek,mmsys.yaml | 28 +++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/Documentation/devicetree/bindings/arm/mediatek/mediatek,mmsys.yaml b/Documentation/devicetree/bindings/arm/mediatek/mediatek,mmsys.yaml
index b3c6888c1457..3f4262e93c78 100644
--- a/Documentation/devicetree/bindings/arm/mediatek/mediatek,mmsys.yaml
+++ b/Documentation/devicetree/bindings/arm/mediatek/mediatek,mmsys.yaml
@@ -93,6 +93,34 @@ properties:
   '#reset-cells':
     const: 1
 
+  port:
+    $ref: /schemas/graph.yaml#/properties/port
+    description:
+      Output port node. This port connects the MMSYS/VDOSYS output to
+      the first component of one display pipeline, for example one of
+      the available OVL or RDMA blocks.
+      Some MediaTek SoCs support multiple display outputs per MMSYS.
+    properties:
+      endpoint at 0:
+        $ref: /schemas/graph.yaml#/properties/endpoint
+        description: Output to the primary display pipeline
+
+      endpoint at 1:
+        $ref: /schemas/graph.yaml#/properties/endpoint
+        description: Output to the secondary display pipeline
+
+      endpoint at 2:
+        $ref: /schemas/graph.yaml#/properties/endpoint
+        description: Output to the tertiary display pipeline
+
+    anyOf:
+      - required:
+          - endpoint at 0
+      - required:
+          - endpoint at 1
+      - required:
+          - endpoint at 2
+
 required:
   - compatible
   - reg
-- 
2.46.0