dt-bindings: i2c: convert i2c-cros-ec-tunnel to json-schema

Convert the google,cros-ec-i2c-tunnel binding to YAML and add it as a
property of google,cros-ec.yaml.

Reviewed-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Signed-off-by: Ricardo Cañuelo <ricardo.canuelo@collabora.com>
Link: https://lore.kernel.org/r/20201021114308.25485-2-ricardo.canuelo@collabora.com
[robh: add ref to i2c-controller.yaml]
Signed-off-by: Rob Herring <robh@kernel.org>

Author: Ricardo Cañuelo

Documentation/devicetree/bindings/i2c/google,cros-ec-i2c-tunnel.yaml

@@ -0,0 +1,66 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+
+$id: http://devicetree.org/schemas/i2c/google,cros-ec-i2c-tunnel.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: I2C bus that tunnels through the ChromeOS EC (cros-ec)
+
+maintainers:
+  - Doug Anderson <dianders@chromium.org>
+  - Benson Leung <bleung@chromium.org>
+  - Enric Balletbo i Serra <enric.balletbo@collabora.com>
+
+description: |
+  On some ChromeOS board designs we've got a connection to the EC
+  (embedded controller) but no direct connection to some devices on the
+  other side of the EC (like a battery and PMIC).  To get access to
+  those devices we need to tunnel our i2c commands through the EC.
+
+  The node for this device should be under a cros-ec node like
+  google,cros-ec-spi or google,cros-ec-i2c.
+
+allOf:
+  - $ref: i2c-controller.yaml#
+
+properties:
+  compatible:
+    const: google,cros-ec-i2c-tunnel
+
+  google,remote-bus:
+    description: The EC bus we'd like to talk to.
+    $ref: /schemas/types.yaml#/definitions/uint32
+
+required:
+  - compatible
+  - google,remote-bus
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    spi0 {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        cros-ec@0 {
+            compatible = "google,cros-ec-spi";
+            reg = <0>;
+            spi-max-frequency = <5000000>;
+
+            i2c-tunnel {
+                compatible = "google,cros-ec-i2c-tunnel";
+                #address-cells = <1>;
+                #size-cells = <0>;
+
+                google,remote-bus = <0>;
+
+                battery: sbs-battery@b {
+                    compatible = "sbs,sbs-battery";
+                    reg = <0xb>;
+                    sbs,poll-retry-count = <1>;
+                };
+            };
+        };
+    };

Documentation/devicetree/bindings/i2c/i2c-cros-ec-tunnel.txt

@@ -71,6 +71,11 @@ properties:
   wakeup-source:
     description: Button can wake-up the system.
 
+patternProperties:
+  "^i2c-tunnel[0-9]*$":
+    type: object
+    $ref: "/schemas/i2c/google,cros-ec-i2c-tunnel.yaml#"
+
 required:
   - compatible