dt-bindings: mfd: Convert ChromeOS EC bindings to json-schema

Convert the ChromeOS EC bindings to json-schema.
Signed-off-by: Ikjoon Jang <ikjn@chromium.org>
Reviewed-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

Documentation/devicetree/bindings/mfd/cros-ec.txt

-ChromeOS Embedded Controller
-
-Google's ChromeOS EC is a Cortex-M device which talks to the AP and
-implements various function such as keyboard and battery charging.
-
-The EC can be connect through various means (I2C, SPI, LPC, RPMSG) and the
-compatible string used depends on the interface. Each connection method has
-its own driver which connects to the top level interface-agnostic EC driver.
-Other Linux driver (such as cros-ec-keyb for the matrix keyboard) connect to
-the top-level driver.
-
-Required properties (I2C):
-- compatible: "google,cros-ec-i2c"
-- reg: I2C slave address
-
-Required properties (SPI):
-- compatible: "google,cros-ec-spi"
-- reg: SPI chip select
-
-Required properties (RPMSG):
-- compatible: "google,cros-ec-rpmsg"
-
-Optional properties (SPI):
-- google,cros-ec-spi-pre-delay: Some implementations of the EC need a little
-  time to wake up from sleep before they can receive SPI transfers at a high
-  clock rate. This property specifies the delay, in usecs, between the
-  assertion of the CS to the start of the first clock pulse.
-- google,cros-ec-spi-msg-delay: Some implementations of the EC require some
-  additional processing time in order to accept new transactions. If the delay
-  between transactions is not long enough the EC may not be able to respond
-  properly to subsequent transactions and cause them to hang. This property
-  specifies the delay, in usecs, introduced between transactions to account
-  for the time required by the EC to get back into a state in which new data
-  can be accepted.
-
-Required properties (LPC):
-- compatible: "google,cros-ec-lpc"
-- reg: List of (IO address, size) pairs defining the interface uses
-
-Optional properties (all):
-- google,has-vbc-nvram: Some implementations of the EC include a small
-  nvram space used to store verified boot context data. This boolean flag
-  is used to specify whether this nvram is present or not.
-
-Example for I2C:
-
-i2c@12ca0000 {
-	cros-ec@1e {
-		reg = <0x1e>;
-		compatible = "google,cros-ec-i2c";
-		interrupts = <14 0>;
-		interrupt-parent = <&wakeup_eint>;
-		wakeup-source;
-	};
-
-
-Example for SPI:
-
-spi@131b0000 {
-	ec@0 {
-		compatible = "google,cros-ec-spi";
-		reg = <0x0>;
-		interrupts = <14 0>;
-		interrupt-parent = <&wakeup_eint>;
-		wakeup-source;
-		spi-max-frequency = <5000000>;
-		controller-data {
-		cs-gpio = <&gpf0 3 4 3 0>;
-		samsung,spi-cs;
-		samsung,spi-feedback-delay = <2>;
-		};
-	};
-};
-
-
-Example for LPC is not supplied as it is not yet implemented.

Documentation/devicetree/bindings/mfd/google,cros-ec.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/mfd/google,cros-ec.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: ChromeOS Embedded Controller
+
+maintainers:
+  - Benson Leung <bleung@chromium.org>
+  - Enric Balletbo i Serra <enric.balletbo@collabora.com>
+  - Guenter Roeck <groeck@chromium.org>
+
+description:
+  Google's ChromeOS EC is a microcontroller which talks to the AP and
+  implements various functions such as keyboard and battery charging.
+  The EC can be connected through various interfaces (I2C, SPI, and others)
+  and the compatible string specifies which interface is being used.
+
+properties:
+  compatible:
+    oneOf:
+      - description:
+          For implementations of the EC is connected through I2C.
+        const: google,cros-ec-i2c
+      - description:
+          For implementations of the EC is connected through SPI.
+        const: google,cros-ec-spi
+      - description:
+          For implementations of the EC is connected through RPMSG.
+        const: google,cros-ec-rpmsg
+
+  google,cros-ec-spi-pre-delay:
+    description:
+      This property specifies the delay in usecs between the
+      assertion of the CS and the first clock pulse.
+    allOf:
+      - $ref: /schemas/types.yaml#/definitions/uint32
+      - default: 0
+      - minimum: 0
+
+  google,cros-ec-spi-msg-delay:
+    description:
+      This property specifies the delay in usecs between messages.
+    allOf:
+      - $ref: /schemas/types.yaml#/definitions/uint32
+      - default: 0
+      - minimum: 0
+
+  google,has-vbc-nvram:
+    description:
+      Some implementations of the EC include a small nvram space used to
+      store verified boot context data. This boolean flag is used to specify
+      whether this nvram is present or not.
+    type: boolean
+
+  spi-max-frequency:
+    description: Maximum SPI frequency of the device in Hz.
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+required:
+  - compatible
+
+if:
+  properties:
+    compatible:
+      contains:
+        enum:
+          - google,cros-ec-i2c
+          - google,cros-ec-rpmsg
+then:
+  properties:
+    google,cros-ec-spi-pre-delay: false
+    google,cros-ec-spi-msg-delay: false
+    spi-max-frequency: false
+
+additionalProperties: false
+
+examples:
+  # Example for I2C
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    i2c0 {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        cros-ec@1e {
+            compatible = "google,cros-ec-i2c";
+            reg = <0x1e>;
+            interrupts = <6 0>;
+            interrupt-parent = <&gpio0>;
+        };
+    };
+
+  # Example for SPI
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    spi0 {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        cros-ec@0 {
+            compatible = "google,cros-ec-spi";
+            reg = <0x0>;
+            google,cros-ec-spi-msg-delay = <30>;
+            google,cros-ec-spi-pre-delay = <10>;
+            interrupts = <99 0>;
+            interrupt-parent = <&gpio7>;
+            spi-max-frequency = <5000000>;
+        };
+    };
+
+  # Example for RPMSG
+  - |
+    scp0 {
+        cros-ec {
+            compatible = "google,cros-ec-rpmsg";
+        };
+    };
+...