dt-bindings: mfd: cros-ec: Add compatible string for UART support

Add a compatible string to support the UART implementation of the cros
ec interface. The driver does not support the reg and interrupt
properties, so exempt them from being required for UART compatible nodes.

Signed-off-by: Bhanu Prakash Maiya <[email protected]>
Co-developed-by: Mark Hasemeyer <[email protected]>
Signed-off-by: Mark Hasemeyer <[email protected]>
Acked-by: Krzysztof Kozlowski <[email protected]>
Signed-off-by: Lee Jones <[email protected]>
Link: https://lore.kernel.org/r/20221207104005.v10.2.I9e018ecb8bdf341648cb64417085978ff0d22a46@changeid

1 files changed, 20 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/mfd/google,cros-ec.yaml b/Documentation/devicetree/bindings/mfd/google,cros-ec.yaml
index 3d5efa5578d1..cdf1d719efe9 100644
--- a/Documentation/devicetree/bindings/mfd/google,cros-ec.yaml
+++ b/Documentation/devicetree/bindings/mfd/google,cros-ec.yaml
@@ -33,6 +33,9 @@ properties:
       - description:
           For implementations of the EC connected through RPMSG.
         const: google,cros-ec-rpmsg
+      - description:
+          For implementations of the EC connected through UART.
+        const: google,cros-ec-uart
 
   controller-data: true
 
@@ -187,6 +190,15 @@ allOf:
       properties:
         mediatek,rpmsg-name: false
 
+  - if:
+      properties:
+        compatible:
+          not:
+            contains:
+              enum:
+                - google,cros-ec-rpmsg
+                - google,cros-ec-uart
+    then:
       required:
         - reg
         - interrupts
@@ -299,4 +311,12 @@ examples:
         vdd-supply = <&pp3300_fp_mcu>;
       };
     };
+
+  # Example for UART
+  - |
+    serial {
+        cros-ec {
+            compatible = "google,cros-ec-uart";
+        };
+    };
 ...