diff --git a/phosphor-regulators/docs/config_file/README.md b/phosphor-regulators/docs/config_file/README.md
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+# phosphor-regulators Configuration File
+
+## Overview
+
+The `phosphor-regulators` application is controlled by a configuration file
+(config file).  The config file defines how to perform the following operations
+on voltage regulators in the system:
+* Modify regulator configuration, such as output voltage or overcurrent
+  settings
+* Read sensor values
+
+The config file does not control how voltage regulators are enabled or how to
+monitor their Power Good (pgood) status.  Those operations are typically
+performed by power sequencer hardware and related firmware.
+
+
+## Data Format
+
+The config file is written using the [JSON (JavaScript Object
+Notation)](https://www.json.org/) data format.
+
+The config file can be created using any text editor, such as Atom, Notepad++,
+gedit, Vim, or Emacs.  You can select any file name, but it must end with the
+".json" suffix, such as `regulators.json`.
+
+
+## Example
+
+See [config_file.json](../../examples/config_file.json).
+
+
+## Contents
+
+### Structure
+
+The config file typically contains the following structure:
+* Array of [rules](rule.md)
+  * Rules defining how to modify configuration of regulators
+  * Rules defining how to read sensors
+* Array of [chassis](chassis.md) in the system
+  * Array of regulator [devices](device.md) in the chassis
+    * Array of voltage [rails](rail.md) produced by the regulator
+
+Rules provide common, reusable sequences of actions that can be shared by one
+or more regulators.  They are optional and can be omitted if each regulator
+requires a unique sequence of actions.
+
+### Syntax
+
+The config file contains a single JSON [config_file](config_file.md) object at
+the root level.  That object contains arrays of other JSON objects.
+
+The following JSON object types are supported:
+* [action](action.md)
+* [and](and.md)
+* [chassis](chassis.md)
+* [compare_presence](compare_presence.md)
+* [compare_vpd](compare_vpd.md)
+* [config_file](config_file.md)
+* [configuration](configuration.md)
+* [device](device.md)
+* [i2c_compare_bit](i2c_compare_bit.md)
+* [i2c_compare_byte](i2c_compare_byte.md)
+* [i2c_compare_bytes](i2c_compare_bytes.md)
+* [i2c_interface](i2c_interface.md)
+* [i2c_write_bit](i2c_write_bit.md)
+* [i2c_write_byte](i2c_write_byte.md)
+* [i2c_write_bytes](i2c_write_bytes.md)
+* [if](if.md)
+* [not](not.md)
+* [or](or.md)
+* [pmbus_read_sensor](pmbus_read_sensor.md)
+* [pmbus_write_vout_command](pmbus_write_vout_command.md)
+* [presence_detection](presence_detection.md)
+* [rail](rail.md)
+* [rule](rule.md)
+* [run_rule](run_rule.md)
+* [sensor_monitoring](sensor_monitoring.md)
+* [set_device](set_device.md)
+
+### Comments
+
+The JSON data format does not support comments.  However, many of the JSON
+objects in the config file provide an optional "comments" property.  The value
+of this property is an array of strings.  Use this property to annotate the
+config file.  The "comments" properties are ignored when the config file is
+read by the `phosphor-regulators` application.
+
+Examples:
+
+```
+"comments": [ "IR35221 regulator producing the Vdd rail" ]
+
+"comments": [ "Check if register 0x82 contains 0x7302",
+              "Device returns bytes in little-endian order",
+              "Ignore most significant bit in each byte" ]
+```
+
+### Hexadecimal Values
+
+The JSON number data type does not support the hexadecimal format.  For this
+reason, properties with hexadecimal values use the string data type.
+
+Example:
+```
+"address": "0x70"
+```
+
+
+## Validation
+
+After creating or modifying a config file, you need to validate it using the
+tool [validate-regulators-config](../../tools/validate-regulators-config).
+
+The validation tool checks the config file for errors, such as:
+* Invalid JSON syntax (like a missing brace)
+* Unrecognized JSON object or property
+* Duplicate rule or device ID
+* Reference to a rule or device ID that does not exist
+* Infinite loop, such as rule A runs rule B which runs rule A
+
+The tool requires two input files:
+* config file to validate
+* [config_schema.json](../../tools/config_schema.json)
+
+The tool has the following command line syntax:
+```
+validate-regulators-config -c <config file> -s config_schema.json
+```
+where `<config file>` is the name of the config file to validate.
+
+
+## Installation
+
+### Standard Directory
+
+`/usr/share/phosphor-regulators`
+
+The standard version of the config file should be installed in this read-only
+directory as part of the firmware image install.  This is the config file that
+will normally be used.
+
+### Test Directory
+
+`/etc/phosphor-regulators`
+
+A new version of the config file can be tested by copying it into this writable
+directory.  This avoids the need to build and install a new firmware image on
+the BMC.
+
+### Search Order
+
+The `phosphor-regulators` application will search first in the test directory
+for a config file.  If no config file is found or the file contains errors, the
+application will next search in the standard directory.
+
+
+## Loading and Reloading
+
+The config file is loaded when the `phosphor-regulators` application starts.
+
+To force the application to reload the config file, use the following command
+on the BMC:
+
+``kill -SIGHUP `pidof phosphor-regulators` ``
+
+
+## Testing
+
+After creating or modifying a config file, you should test it to ensure it
+provides the desired behavior.
+
+Perform the following steps to test the config file:
+* Run the [validation tool](#validation) to ensure the config file contains no
+  errors.
+* Copy the config file into the [test directory](#test-directory) on the BMC.
+* Force the `phosphor-regulators` application to
+  [reload](#loading-and-reloading) its config file, causing it to find and load
+  the file in the test directory.
+* Boot the system.  Regulator configuration changes (such as voltage settings)
+  are only applied during the boot.
+
+When finished testing, perform the following steps to revert to the standard
+config file:
+* Remove the config file from the test directory.
+* Force the `phosphor-regulators` application to reload its config file,
+  causing it to find and load the file in the standard directory.
+* Boot the system, if necessary, to apply the regulator configuration changes
+  in the standard config file.
diff --git a/phosphor-regulators/docs/config_file/config_file.md b/phosphor-regulators/docs/config_file/config_file.md
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+# config_file
+
+## Description
+The root (outer-most) object in a phosphor-regulators configuration file.
+
+## Properties
+| Name | Required | Type | Description |
+| :--- | :------: | :--- | :---------- |
+| comments | no | array of strings | One or more comment lines describing this file. |
+| rules | no | array of [rules](rule.md) | One or more rules shared by regulators in this file. |
+| chassis | yes | array of [chassis](chassis.md) | One or more chassis in the system. |
+
+## Example
+```
+{
+  "comments": [ "Config file for a FooBar one-chassis system" ],
+  "rules": [
+    {
+      "id": "set_voltage_rule",
+      ... details omitted ...
+    },
+    {
+      "id": "read_sensors_rule",
+      ... details omitted ...
+    }
+  ],
+  "chassis": [
+    {
+      "number": 1,
+      "devices": [
+        ... details omitted ...
+      ]
+    }
+  ]
+}
+```
diff --git a/phosphor-regulators/examples/config_file.json b/phosphor-regulators/examples/config_file.json
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+{
+  "comments": [ "Config file for a FooBar one-chassis system" ],
+
+  "rules": [
+    {
+      "comments": [ "Sets output voltage for a PMBus regulator rail" ],
+      "id": "set_voltage_rule",
+      "actions": [
+        {
+          "pmbus_write_vout_command": {
+            "format": "linear"
+          }
+        }
+      ]
+    },
+
+    {
+      "comments": [ "Reads sensors from a PMBus regulator rail" ],
+      "id": "read_sensors_rule",
+      "actions": [
+        {
+          "comments": [ "Read output voltage from READ_VOUT." ],
+          "pmbus_read_sensor": {
+            "type": "vout",
+            "command": "0x8B",
+            "format": "linear_16"
+          }
+        },
+
+        {
+          "comments": [ "Read output current from READ_IOUT." ],
+          "pmbus_read_sensor": {
+            "type": "iout",
+            "command": "0x8C",
+            "format": "linear_11"
+          }
+        },
+
+        {
+          "comments": [ "Read temperature from READ_TEMPERATURE_1." ],
+          "pmbus_read_sensor": {
+            "type": "temperature",
+            "command": "0x8D",
+            "format": "linear_11"
+          }
+        }
+      ]
+    }
+  ],
+
+  "chassis": [
+    {
+      "comments": [ "Chassis number 1 containing CPUs and memory" ],
+      "number": 1,
+      "devices": [
+        {
+          "comments": [ "IR35221 regulator producing the Vdd rail" ],
+          "id": "vdd_regulator",
+          "is_regulator": true,
+          "fru": "/system/chassis/motherboard/regulator1",
+          "i2c_interface": {
+            "bus": 1,
+            "address": "0x70"
+          },
+          "rails": [
+            {
+              "comments": [ "Vdd rail" ],
+              "id": "vdd",
+              "configuration": {
+                "volts": 1.03,
+                "rule_id": "set_voltage_rule"
+              },
+              "sensor_monitoring": {
+                "rule_id": "read_sensors_rule"
+              }
+            }
+          ]
+        },
+
+        {
+          "comments": [ "IR35221 regulator producing the Vio rail" ],
+          "id": "vio_regulator",
+          "is_regulator": true,
+          "fru": "/system/chassis/motherboard/regulator2",
+          "i2c_interface": {
+            "bus": 1,
+            "address": "0x71"
+          },
+          "rails": [
+            {
+              "comments": [ "Vio rail" ],
+              "id": "vio",
+              "configuration": {
+                "volts": 1.1,
+                "rule_id": "set_voltage_rule"
+              },
+              "sensor_monitoring": {
+                "rule_id": "read_sensors_rule"
+              }
+            }
+          ]
+        }
+      ]
+    }
+  ]
+}