dt-bindings: display: ti,am65x-dss: Add support for AM62L DSS

The DSS controller on TI's AM62L SoC is an update from that on TI's
AM625/AM65x/AM62A7 SoC. The AM62L DSS [1] only supports a single display
pipeline using a single overlay manager, single video port and a single
video lite pipeline which does not support scaling.

The output of video port is routed to SoC boundary via DPI interface and
the DPI signals from the video port are also routed to DSI Tx controller
present within the SoC.

[1]: Section 11.7 (Display Subsystem and Peripherals)
Link : https://www.ti.com/lit/pdf/sprujb4

Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Reviewed-by: Jayesh Choudhary <j-choudhary@ti.com>
Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Signed-off-by: Devarsh Thakkar <devarsht@ti.com>
Link: https://lore.kernel.org/r/20250507180631.874930-2-devarsht@ti.com
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>

Documentation/devicetree/bindings/display/ti/ti,am65x-dss.yaml

@@ -12,18 +12,25 @@ maintainers:
   - Tomi Valkeinen <tomi.valkeinen@ti.com>
 
 description: |
-  The AM625 and AM65x TI Keystone Display SubSystem with two output
+  The AM625 and AM65x TI Keystone Display SubSystem has two output
   ports and two video planes. In AM65x DSS, the first video port
   supports 1 OLDI TX and in AM625 DSS, the first video port output is
   internally routed to 2 OLDI TXes. The second video port supports DPI
   format. The first plane is full video plane with all features and the
   second is a "lite plane" without scaling support.
+  The AM62L display subsystem has a single output port which supports DPI
+  format but it only supports single video "lite plane" which does not support
+  scaling. The output port is routed to SoC boundary via DPI interface and same
+  DPI signals are also routed internally to DSI Tx controller present within the
+  SoC. Due to clocking limitations only one of the interface i.e. either DSI or
+  DPI can be used at once.
 
 properties:
   compatible:
     enum:
       - ti,am625-dss
       - ti,am62a7-dss
+      - ti,am62l-dss
       - ti,am65x-dss
 
   reg:
@@ -91,6 +98,8 @@ properties:
           For AM625 DSS, the internal DPI output port node from video
           port 1.
           For AM62A7 DSS, the port is tied off inside the SoC.
+          For AM62L DSS, the DSS DPI output port node from video port 1
+          or DSI Tx controller node connected to video port 1.
 
       port@1:
         $ref: /schemas/graph.yaml#/properties/port
@@ -123,6 +132,16 @@ allOf:
         ports:
           properties:
             port@0: false
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: ti,am62l-dss
+    then:
+      properties:
+        ports:
+          properties:
+            port@1: false
 
 required:
   - compatible