[PATCH v5 1/3] dt-bindings: mfd: Add Gateworks System Controller bindings

[Tim Harvey <tharvey@gateworks.com>]

This patch adds documentation of device-tree bindings for the
Gateworks System Controller (GSC).

Signed-off-by: Tim Harvey <tharvey@gateworks.com>
---
v5:
 - resolve dt_binding_check issues

v4:
 - move to using pwm<n>_auto_point<m>_{pwm,temp} for FAN PWM
 - remove unncessary resolution/scaling properties for ADCs
 - update to yaml
 - remove watchdog

v3:
 - replaced _ with -
 - remove input bindings
 - added full description of hwmon
 - fix unit address of hwmon child nodes
---
 .../devicetree/bindings/mfd/gateworks-gsc.yaml     | 158 +++++++++++++++++++++
 1 file changed, 158 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/mfd/gateworks-gsc.yaml

diff --git a/Documentation/devicetree/bindings/mfd/gateworks-gsc.yaml b/Documentation/devicetree/bindings/mfd/gateworks-gsc.yaml
new file mode 100644
index 00000000..f7c1a05
--- /dev/null
+++ b/Documentation/devicetree/bindings/mfd/gateworks-gsc.yaml
@@ -0,0 +1,158 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/mfd/gateworks-gsc.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Gateworks System Controller multi-function device
+
+description: |
+  The GSC is a Multifunction I2C slave device with the following submodules:
+   - Watchdog Timer
+   - GPIO
+   - Pushbutton controller
+   - Hardware Monitore with ADC's for temperature and voltage rails and
+     fan controller
+
+maintainers:
+  - Tim Harvey <tharvey@gateworks.com>
+  - Robert Jones <rjones@gateworks.com>
+
+properties:
+  $nodename:
+    pattern: "gsc@[0-9a-f]{1,2}"
+  compatible:
+    const: gw,gsc
+
+  reg:
+    description: I2C device address
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  interrupt-controller: true
+
+  "#interrupt-cells":
+    const: 1
+    description: The IRQ number
+
+  hwmon:
+    type: object
+    description: Optional Hardware Monitoring module
+
+    properties:
+      compatible:
+        const: gw,gsc-hwmon
+
+      "#address-cells":
+        const: 1
+
+      "#size-cells":
+        const: 0
+
+      gw,fan-base:
+        $ref: /schemas/types.yaml#/definitions/uint32
+        description: The fan controller base address
+
+    patternProperties:
+      "^adc@[0-2]$":
+        type: object
+        description: |
+          Properties for a single ADC which can report cooked values
+          (ie temperature sensor based on thermister), raw values
+          (ie voltage rail with a pre-scaling resistor divider).
+
+        properties:
+          reg:
+            description: Register of the ADC
+            maxItems: 1
+
+          label:
+            description: Name of the ADC input
+
+          type:
+            description: |
+              temperature in C*10 (temperature),
+              pre-scaled voltage value (voltage),
+              or scaled based on an optional resistor divider and optional
+              offset (voltage-raw)
+            enum:
+              - temperature
+              - voltage
+              - voltage-raw
+
+          gw,voltage-divider:
+            allOf:
+              - $ref: /schemas/types.yaml#/definitions/uint32-array
+            description: values of resistors for divider on raw ADC input
+            items:
+              - description: R1
+              - description: R2
+
+          gw,voltage-offset:
+            $ref: /schemas/types.yaml#/definitions/uint32
+            description: |
+              A positive uV voltage offset to apply to a raw ADC
+              (ie to compensate for a diode drop).
+
+        required:
+          - type
+          - reg
+          - label
+
+    required:
+      - compatible
+      - "#address-cells"
+      - "#size-cells"
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - interrupt-controller
+  - "#interrupt-cells"
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        gsc@20 {
+            compatible = "gw,gsc";
+            reg = <0x20>;
+            interrupt-parent = <&gpio1>;
+            interrupts = <4 GPIO_ACTIVE_LOW>;
+            interrupt-controller;
+            #interrupt-cells = <1>;
+
+            hwmon {
+                compatible = "gw,gsc-hwmon";
+                #address-cells = <1>;
+                #size-cells = <0>;
+                gw,fan-base = <0x2c>;
+
+                adc@0 { /* A0: Board Temperature */
+                    type = "temperature";
+                    reg = <0x00>;
+                    label = "temp";
+                };
+
+                adc@2 { /* A1: Input Voltage (raw ADC) */
+                    type = "voltage-raw";
+                    reg = <0x02>;
+                    label = "vdd_vin";
+                    gw,voltage-divider = <22100 1000>;
+                    gw,voltage-offset = <800000>;
+                };
+
+                adc@b { /* A2: Battery voltage */
+                    type = "voltage";
+                    reg = <0x0b>;
+                    label = "vdd_bat";
+                };
+            };
+        };
+    };
-- 
2.7.4