dt-bindings: phy: mixel: mipi-dsi-phy: Add Mixel combo PHY support for i.MX8qxp

Add support for Mixel MIPI DPHY + LVDS PHY combo IP
as found on Freescale i.MX8qxp SoC.

Cc: Guido Günther <agx@sigxcpu.org>
Cc: Kishon Vijay Abraham I <kishon@ti.com>
Cc: Vinod Koul <vkoul@kernel.org>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: NXP Linux Team <linux-imx@nxp.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Guido Günther <agx@sigxcpu.org>
Signed-off-by: Liu Ying <victor.liu@nxp.com>
Link: https://lore.kernel.org/r/20220419010852.452169-5-victor.liu@nxp.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

Documentation/devicetree/bindings/phy/mixel,mipi-dsi-phy.yaml

@@ -14,10 +14,14 @@ description: |
   MIPI-DSI IP from Northwest Logic). It represents the physical layer for the
   electrical signals for DSI.
 
+  The Mixel PHY IP block found on i.MX8qxp is a combo PHY that can work
+  in either MIPI-DSI PHY mode or LVDS PHY mode.
+
 properties:
   compatible:
     enum:
       - fsl,imx8mq-mipi-dphy
+      - fsl,imx8qxp-mipi-dphy
 
   reg:
     maxItems: 1
@@ -40,6 +44,11 @@ properties:
   "#phy-cells":
     const: 0
 
+  fsl,syscon:
+    $ref: /schemas/types.yaml#/definitions/phandle
+    description: |
+      A phandle which points to Control and Status Registers(CSR) module.
+
   power-domains:
     maxItems: 1
 
@@ -48,12 +57,38 @@ required:
   - reg
   - clocks
   - clock-names
-  - assigned-clocks
-  - assigned-clock-parents
-  - assigned-clock-rates
   - "#phy-cells"
   - power-domains
 
+allOf:
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: fsl,imx8mq-mipi-dphy
+    then:
+      properties:
+        fsl,syscon: false
+
+      required:
+        - assigned-clocks
+        - assigned-clock-parents
+        - assigned-clock-rates
+
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: fsl,imx8qxp-mipi-dphy
+    then:
+      properties:
+        assigned-clocks: false
+        assigned-clock-parents: false
+        assigned-clock-rates: false
+
+      required:
+        - fsl,syscon
+
 additionalProperties: false
 
 examples: