diff --git a/phosphor-regulators/src/device.hpp b/phosphor-regulators/src/device.hpp
new file mode 100644
index 0000000..3b3a91b
--- /dev/null
+++ b/phosphor-regulators/src/device.hpp
@@ -0,0 +1,71 @@
+/**
+ * Copyright © 2019 IBM Corporation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#pragma once
+
+#include <string>
+
+namespace phosphor
+{
+namespace power
+{
+namespace regulators
+{
+
+/**
+ * @class Device
+ *
+ * A hardware device, such as a voltage regulator or I/O expander.
+ */
+class Device
+{
+  public:
+    // Specify which compiler-generated methods we want
+    Device() = delete;
+    Device(const Device&) = delete;
+    Device(Device&&) = delete;
+    Device& operator=(const Device&) = delete;
+    Device& operator=(Device&&) = delete;
+    ~Device() = default;
+
+    /**
+     * Constructor.
+     *
+     * @param id unique device ID
+     */
+    Device(const std::string& id) : id{id}
+    {
+    }
+
+    /**
+     * Returns the unique ID of this device.
+     *
+     * @return device ID
+     */
+    const std::string& getId() const
+    {
+        return id;
+    }
+
+  private:
+    /**
+     * Unique ID of this device.
+     */
+    const std::string id{};
+};
+
+} // namespace regulators
+} // namespace power
+} // namespace phosphor
diff --git a/phosphor-regulators/src/meson.build b/phosphor-regulators/src/meson.build
new file mode 100644
index 0000000..19f1bb5
--- /dev/null
+++ b/phosphor-regulators/src/meson.build
@@ -0,0 +1 @@
+# subdir('actions')
diff --git a/phosphor-regulators/src/rail.hpp b/phosphor-regulators/src/rail.hpp
new file mode 100644
index 0000000..3fa516b
--- /dev/null
+++ b/phosphor-regulators/src/rail.hpp
@@ -0,0 +1,74 @@
+/**
+ * Copyright © 2019 IBM Corporation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#pragma once
+
+#include <string>
+
+namespace phosphor
+{
+namespace power
+{
+namespace regulators
+{
+
+/**
+ * @class Rail
+ *
+ * A voltage rail produced by a voltage regulator.
+ *
+ * Voltage regulators produce one or more rails.  Each rail typically provides a
+ * different output voltage level, such as 1.1V.
+ */
+class Rail
+{
+  public:
+    // Specify which compiler-generated methods we want
+    Rail() = delete;
+    Rail(const Rail&) = delete;
+    Rail(Rail&&) = delete;
+    Rail& operator=(const Rail&) = delete;
+    Rail& operator=(Rail&&) = delete;
+    ~Rail() = default;
+
+    /**
+     * Constructor.
+     *
+     * @param id unique rail ID
+     */
+    Rail(const std::string& id) : id{id}
+    {
+    }
+
+    /**
+     * Returns the unique ID of this rail.
+     *
+     * @return rail ID
+     */
+    const std::string& getId() const
+    {
+        return id;
+    }
+
+  private:
+    /**
+     * Unique ID of this rail.
+     */
+    const std::string id{};
+};
+
+} // namespace regulators
+} // namespace power
+} // namespace phosphor
diff --git a/phosphor-regulators/src/rule.hpp b/phosphor-regulators/src/rule.hpp
new file mode 100644
index 0000000..ccc47fa
--- /dev/null
+++ b/phosphor-regulators/src/rule.hpp
@@ -0,0 +1,78 @@
+/**
+ * Copyright © 2019 IBM Corporation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#pragma once
+
+#include <string>
+
+namespace phosphor
+{
+namespace power
+{
+namespace regulators
+{
+
+/**
+ * @class Rule
+ *
+ * A rule is a sequence of actions that can be shared by multiple voltage
+ * regulators.
+ *
+ * Rules define a standard way to perform an operation.  For example, the
+ * following action sequences might be sharable using a rule:
+ * - Actions that set the output voltage of a regulator rail
+ * - Actions that read all the sensors of a regulator rail
+ * - Actions that detect down-level hardware using version registers
+ */
+class Rule
+{
+  public:
+    // Specify which compiler-generated methods we want
+    Rule() = delete;
+    Rule(const Rule&) = delete;
+    Rule(Rule&&) = delete;
+    Rule& operator=(const Rule&) = delete;
+    Rule& operator=(Rule&&) = delete;
+    ~Rule() = default;
+
+    /**
+     * Constructor.
+     *
+     * @param id unique rule ID
+     */
+    Rule(const std::string& id) : id{id}
+    {
+    }
+
+    /**
+     * Returns the unique ID of this rule.
+     *
+     * @return rule ID
+     */
+    const std::string& getId() const
+    {
+        return id;
+    }
+
+  private:
+    /**
+     * Unique ID of this rule.
+     */
+    const std::string id{};
+};
+
+} // namespace regulators
+} // namespace power
+} // namespace phosphor