[PATCH v6] mfd: google,cros-ec: add DT bindings for a baseboard's switch device

[Ikjoon Jang]

This is for ChromeOS tablets which have a 'cros_cbas' switch device
in the "Whiskers" base board. This device can be instantiated only by
device tree on ARM platforms. ChromeOS EC doesn't provide a way to
probe the device.

Signed-off-by: Ikjoon Jang <ikjn@xxxxxxxxxxxx>
Reviewed-by: Rob Herring <robh@xxxxxxxxxx>
Acked-by: Enric Balletbo i Serra <enric.balletbo@xxxxxxxxxxxxx>

---

Changes in v6:
 - Remove a label from cbas node in an example

Changes in v5:
 - Add missing blank lines and change the description property's position.
 - Add a note to description: "this device cannot be detected at runtime."

Changes in v4:
Define cros-cbase bindings inside google,cros-ec.yaml instead of
a separated binding document.

 .../bindings/mfd/google,cros-ec.yaml          | 20 +++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/Documentation/devicetree/bindings/mfd/google,cros-ec.yaml b/Documentation/devicetree/bindings/mfd/google,cros-ec.yaml
index 76bf16ee27ec..929c17552d8b 100644
--- a/Documentation/devicetree/bindings/mfd/google,cros-ec.yaml
+++ b/Documentation/devicetree/bindings/mfd/google,cros-ec.yaml
@@ -114,6 +114,22 @@ properties:
       - "#address-cells"
       - "#size-cells"
 
+  cbas:
+    type: object
+
+    description:
+      This device is used to signal when a detachable base is attached
+      to a Chrome OS tablet. This device cannot be detected at runtime.
+
+    properties:
+      compatible:
+        const: google,cros-cbas
+
+    required:
+      - compatible
+
+    additionalProperties: false
+
 patternProperties:
   "^i2c-tunnel[0-9]*$":
     type: object
@@ -180,6 +196,10 @@ examples:
             interrupts = <99 0>;
             interrupt-parent = <&gpio7>;
             spi-max-frequency = <5000000>;
+
+            cbas {
+                compatible = "google,cros-cbas";
+            };
         };
     };
 
-- 
2.31.1.607.g51e8a6a459-goog