dt-bindings: firmware: amlogic,scpi: Convert to json schema

Convert/merge the existing text format SCPI binding additions for
amlogic,scpi into the common arm,scpi json scheme.

Couple of things to note:
"amlogic,meson-gxbb-scpi" is always used with "arm,scpi-pre-1.0" and
"amlogic,meson-gxbb-scpi-sensors" is used always with "arm,scpi-sensors"

Cc: Rob Herring <robh+dt@kernel.org>
Cc: Kevin Hilman <khilman@baylibre.com>
Cc: Neil Armstrong <narmstrong@baylibre.com>
Cc: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Link: https://lore.kernel.org/r/20210604205710.1944363-4-sudeep.holla@arm.comSigned-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/arm/amlogic,scpi.txt

-System Control and Power Interface (SCPI) Message Protocol
-(in addition to the standard binding in [0])
-----------------------------------------------------------
-Required properties
-
-- compatible : should be "amlogic,meson-gxbb-scpi"
-
-Sensor bindings for the sensors based on SCPI Message Protocol
---------------------------------------------------------------
-SCPI provides an API to access the various sensors on the SoC.
-
-Required properties:
-- compatible : should be "amlogic,meson-gxbb-scpi-sensors".
-
-[0] Documentation/devicetree/bindings/arm/arm,scpi.txt

Documentation/devicetree/bindings/firmware/arm,scpi.yaml

@@ -32,6 +32,10 @@ properties:
     oneOf:
       - const: arm,scpi               # SCPI v1.0 and above
       - const: arm,scpi-pre-1.0       # Unversioned SCPI before v1.0
+      - items:
+          - enum:
+              - amlogic,meson-gxbb-scpi
+          - const: arm,scpi-pre-1.0
 
   mboxes:
     description:
@@ -81,7 +85,12 @@ properties:
 
     properties:
       compatible:
-        const: arm,scpi-sensors
+        oneOf:
+          - const: arm,scpi-sensors
+          - items:
+              - enum:
+                  - amlogic,meson-gxbb-scpi-sensors
+              - const: arm,scpi-sensors
 
       '#thermal-sensor-cells':
         const: 1
@@ -222,4 +231,17 @@ examples:
         };
     };
 
+  - |
+    firmware {
+        scpi {
+            compatible = "amlogic,meson-gxbb-scpi", "arm,scpi-pre-1.0";
+            mboxes = <&mailbox 1 &mailbox 2>;
+            shmem = <&cpu_scp_lpri &cpu_scp_hpri>;
+
+            scpi_sensors1: sensors {
+                compatible = "amlogic,meson-gxbb-scpi-sensors", "arm,scpi-sensors";
+                #thermal-sensor-cells = <1>;
+            };
+        };
+    };
 ...