dt-bindings: sun6i-dsi: Document A64 MIPI-DSI controller

The MIPI DSI controller in Allwinner A64 is similar to A33.

But unlike A33, A64 doesn't have DSI_SCLK gating so it is valid
to have separate compatible for A64 on the same driver.

DSI_SCLK uses mod clock-names on dt-bindings, so the same
is not required for A64.

On that note
- A64 require minimum of 1 clock like the bus clock
- A33 require minimum of 2 clocks like both bus, mod clocks

So, update dt-bindings so-that it can document both A33,
A64 bindings requirements.

Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20191222132229.30276-2-jagan@amarulasolutions.com

Documentation/devicetree/bindings/display/allwinner,sun6i-a31-mipi-dsi.yaml

@@ -15,7 +15,9 @@ properties:
   "#size-cells": true
 
   compatible:
-    const: allwinner,sun6i-a31-mipi-dsi
+    enum:
+      - allwinner,sun6i-a31-mipi-dsi
+      - allwinner,sun50i-a64-mipi-dsi
 
   reg:
     maxItems: 1
@@ -24,6 +26,8 @@ properties:
     maxItems: 1
 
   clocks:
+    minItems: 1
+    maxItems: 2
     items:
       - description: Bus Clock
       - description: Module Clock
@@ -63,13 +67,38 @@ required:
   - reg
   - interrupts
   - clocks
-  - clock-names
   - phys
   - phy-names
   - resets
   - vcc-dsi-supply
   - port
 
+allOf:
+  - if:
+      properties:
+         compatible:
+           contains:
+             const: allwinner,sun6i-a31-mipi-dsi
+
+    then:
+        properties:
+          clocks:
+            minItems: 2
+
+        required:
+          - clock-names
+
+  - if:
+      properties:
+         compatible:
+           contains:
+             const: allwinner,sun50i-a64-mipi-dsi
+
+    then:
+        properties:
+          clocks:
+            minItems: 1
+
 additionalProperties: false
 
 examples: