diff --git a/phosphor-regulators/docs/config_file/chassis.md b/phosphor-regulators/docs/config_file/chassis.md
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+# chassis
+
+## Description
+A chassis within the system.
+
+Chassis are large enclosures that can be independently powered off and on by
+the BMC.  Small and mid-sized systems may contain a single chassis.  In a large
+rack-mounted system, each drawer may correspond to a chassis.
+
+A chassis only needs to be defined in the config file if it contains regulators
+that need to be configured or monitored.
+
+## Properties
+| Name | Required | Type | Description |
+| :--- | :------: | :--- | :---------- |
+| comments | no | array of strings | One or more comment lines describing this chassis. |
+| number | yes | number | Chassis number within the system.  Chassis numbers start at 1 because chassis 0 represents the entire system. |
+| devices | no | array of [devices](device.md) | One or more devices within the chassis.  The array should contain regulator devices and any related devices required to perform regulator operations. |
+
+## Example
+```
+{
+  "comments": [ "Chassis number 1 containing CPUs and memory" ],
+  "number": 1,
+  "devices": [
+    {
+      "id": "vdd_regulator",
+      ... details omitted ...
+    },
+    {
+      "id": "vio_regulator",
+      ... details omitted ...
+    }
+  ]
+}
+```
diff --git a/phosphor-regulators/docs/config_file/device.md b/phosphor-regulators/docs/config_file/device.md
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+# device
+
+## Description
+A hardware device within the chassis.
+
+The following devices should be defined in the config file:
+* Voltage regulators that require configuration or monitoring.
+* Other devices that are required to configure or monitor regulators.  For
+  example, an I/O expander may provide necessary information about a regulator.
+
+## Properties
+| Name | Required | Type | Description |
+| :--- | :------: | :--- | :---------- |
+| comments | no | array of strings | One or more comment lines describing this device. |
+| id | yes | string | Unique ID for this device.  Can only contain letters (A-Z, a-z), numbers (0-9), and underscore (\_). |
+| is_regulator | yes | boolean (true or false) | Indicates whether this device is a voltage regulator (phase controller). |
+| fru | yes | string | Field-Replaceable Unit (FRU) for this device.  Specify the D-Bus inventory path of the FRU.  If the device itself is not a FRU, specify the FRU that contains it. |
+| i2c_interface | yes | [i2c_interface](i2c_interface.md) | I2C interface to this device. |
+| presence_detection | no | [presence_detection](presence_detection.md) | Specifies how to detect whether this device is present.  If this property is not specified, the device is assumed to always be present. |
+| configuration | no | [configuration](configuration.md) | Specifies configuration changes that should be applied to this device.  These changes usually override hardware default settings.  The configuration changes are applied during the boot before regulators are enabled. |
+| rails | no | array of [rails](rail.md) | One or more voltage rails produced by this device.  This property can only be specified if the "is_regulator" property is true. |
+
+## Example
+```
+{
+  "comments": [ "IR35221 regulator producing the Vdd rail" ],
+  "id": "vdd_regulator",
+  "is_regulator": true,
+  "fru": "/system/chassis/motherboard/regulator2",
+  "i2c_interface": {
+    "bus": 1,
+    "address": "0x70"
+  },
+  "configuration": {
+    "rule_id": "configure_ir35221_rule"
+  },
+  "rails": [
+    {
+      "id": "vdd",
+      ... details omitted ...
+    }
+  ]
+}
+```
diff --git a/phosphor-regulators/docs/config_file/i2c_interface.md b/phosphor-regulators/docs/config_file/i2c_interface.md
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+# i2c_interface
+
+## Description
+I2C interface to a device.
+
+Direct I2C communication to the device will be performed using the [i2c-dev
+API](https://www.kernel.org/doc/Documentation/i2c/dev-interface).
+
+To avoid race conditions and conflicts, no device driver should be bound to the
+device.
+
+## Properties
+| Name | Required | Type | Description |
+| :--- | :------: | :--- | :---------- |
+| bus  | yes | number | I2C bus number of the device.  The first bus is 0. |
+| address  | yes | string | 7-bit I2C address of the device expressed in hexadecimal.  Must be prefixed with 0x and surrounded by double quotes. |
+
+## Example
+```
+{
+  "bus": 1,
+  "address": "0x70"
+}
+```
diff --git a/phosphor-regulators/docs/config_file/rail.md b/phosphor-regulators/docs/config_file/rail.md
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+# rail
+
+## Description
+A voltage rail produced by a regulator.
+
+Voltage regulators produce one or more rails.  Each rail typically provides a
+different output voltage level, such as 1.1V.
+
+On a PMBus regulator with multiple rails, the current rail is selected using
+the PAGE command.  Subsequent PMBus commands are sent to that PAGE/rail.
+
+## Properties
+| Name | Required | Type | Description |
+| :--- | :------: | :--- | :---------- |
+| comments | no | array of strings | One or more comment lines describing this rail. |
+| id | yes | string | Unique ID for this rail.  Can only contain letters (A-Z, a-z), numbers (0-9), and underscore (\_). |
+| configuration | no | [configuration](configuration.md) | Specifies configuration changes that should be applied to this rail.  These changes usually override hardware default settings.  The configuration changes are applied during the boot before regulators are enabled. |
+| sensor_monitoring | no | [sensor_monitoring](sensor_monitoring.md) | Specifies how to read the sensors for this rail. |
+
+## Example
+```
+{
+  "comments": [ "Vdd rail on PAGE 0 of the Vdd/Vio regulator" ],
+  "id": "vdd",
+  "configuration": {
+    "volts": 1.1,
+    "rule_id": "set_page0_voltage_rule"
+  },
+  "sensor_monitoring": {
+    "rule_id": "read_ir35221_page0_sensors_rule"
+  }
+}
+```