diff --git a/phosphor-power-sequencer/src/services.hpp b/phosphor-power-sequencer/src/services.hpp
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+/**
+ * Copyright © 2024 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 "pmbus.hpp"
+#include "xyz/openbmc_project/Logging/Entry/server.hpp"
+
+#include <fmt/format.h>
+
+#include <phosphor-logging/lg2.hpp>
+#include <sdbusplus/bus.hpp>
+#include <sdbusplus/exception.hpp>
+
+#include <cstdint>
+#include <map>
+#include <memory>
+#include <string>
+#include <vector>
+
+namespace phosphor::power::sequencer
+{
+
+using namespace sdbusplus::xyz::openbmc_project::Logging::server;
+using PMBusBase = phosphor::pmbus::PMBusBase;
+using PMBus = phosphor::pmbus::PMBus;
+
+/**
+ * @class Services
+ *
+ * Abstract base class that provides an interface to system services like error
+ * logging and the journal.
+ */
+class Services
+{
+  public:
+    // Specify which compiler-generated methods we want
+    Services() = default;
+    Services(const Services&) = delete;
+    Services(Services&&) = delete;
+    Services& operator=(const Services&) = delete;
+    Services& operator=(Services&&) = delete;
+    virtual ~Services() = default;
+
+    /**
+     * Returns the D-Bus bus object.
+     *
+     * @return D-Bus bus
+     */
+    virtual sdbusplus::bus_t& getBus() = 0;
+
+    /**
+     * Logs an error message in the system journal.
+     *
+     * @param message message to log
+     */
+    virtual void logErrorMsg(const std::string& message) = 0;
+
+    /**
+     * Logs an informational message in the system journal.
+     *
+     * @param message message to log
+     */
+    virtual void logInfoMsg(const std::string& message) = 0;
+
+    /**
+     * Logs an error.
+     *
+     * If logging fails, a message is written to the system journal but an
+     * exception is not thrown.
+     *
+     * @param message Message property of the error log entry
+     * @param severity Severity property of the error log entry
+     * @param additionalData AdditionalData property of the error log entry
+     */
+    virtual void
+        logError(const std::string& message, Entry::Level severity,
+                 std::map<std::string, std::string>& additionalData) = 0;
+
+    /**
+     * Returns whether the hardware with the specified inventory path is
+     * present.
+     *
+     * Throws an exception if an error occurs while obtaining the presence
+     * value.
+     *
+     * @param inventoryPath D-Bus inventory path of the hardware
+     * @return true if hardware is present, false otherwise
+     */
+    virtual bool isPresent(const std::string& inventoryPath) = 0;
+
+    /**
+     * Reads all the GPIO values on the chip with the specified label.
+     *
+     * Throws an exception if an error occurs while obtaining the values.
+     *
+     * @param chipLabel label identifying the chip with the GPIOs
+     * @return GPIO values
+     */
+    virtual std::vector<int> getGPIOValues(const std::string& chipLabel) = 0;
+
+    /**
+     * Creates object for communicating with a PMBus device by reading and
+     * writing sysfs files.
+     *
+     * Throws an exception if an error occurs.
+     *
+     * @param bus I2C bus
+     * @param address I2C address
+     * @param driverName Device driver name
+     * @param instance Chip instance number
+     * @return object for communicating with PMBus device
+     */
+    virtual std::unique_ptr<PMBusBase>
+        createPMBus(uint8_t bus, uint16_t address,
+                    const std::string& driverName = "",
+                    size_t instance = 0) = 0;
+};
+
+/**
+ * @class BMCServices
+ *
+ * Implementation of the Services interface using standard BMC system services.
+ */
+class BMCServices : public Services
+{
+  public:
+    // Specify which compiler-generated methods we want
+    BMCServices() = delete;
+    BMCServices(const BMCServices&) = delete;
+    BMCServices(BMCServices&&) = delete;
+    BMCServices& operator=(const BMCServices&) = delete;
+    BMCServices& operator=(BMCServices&&) = delete;
+    virtual ~BMCServices() = default;
+
+    /**
+     * Constructor.
+     *
+     * @param bus D-Bus bus object
+     */
+    explicit BMCServices(sdbusplus::bus_t& bus) : bus{bus} {}
+
+    /** @copydoc Services::getBus() */
+    virtual sdbusplus::bus_t& getBus() override
+    {
+        return bus;
+    }
+
+    /** @copydoc Services::logErrorMsg() */
+    virtual void logErrorMsg(const std::string& message) override
+    {
+        lg2::error(message.c_str());
+    }
+
+    /** @copydoc Services::logInfoMsg() */
+    virtual void logInfoMsg(const std::string& message) override
+    {
+        lg2::info(message.c_str());
+    }
+
+    /** @copydoc Services::logError() */
+    virtual void
+        logError(const std::string& message, Entry::Level severity,
+                 std::map<std::string, std::string>& additionalData) override;
+
+    /** @copydoc Services::isPresent() */
+    virtual bool isPresent(const std::string& inventoryPath) override;
+
+    /** @copydoc Services::getGPIOValues() */
+    virtual std::vector<int>
+        getGPIOValues(const std::string& chipLabel) override;
+
+    /** @copydoc Services::createPMBus() */
+    virtual std::unique_ptr<PMBusBase>
+        createPMBus(uint8_t bus, uint16_t address,
+                    const std::string& driverName = "",
+                    size_t instance = 0) override
+    {
+        std::string path = fmt::format("/sys/bus/i2c/devices/{}-{:04x}", bus,
+                                       address);
+        return std::make_unique<PMBus>(path, driverName, instance);
+    }
+
+  private:
+    /**
+     * Returns whether the specified D-Bus exception is one of the expected
+     * types that can be thrown if hardware is not present.
+     *
+     * @return true if exception type is expected, false otherwise
+     */
+    bool isExpectedException(const sdbusplus::exception_t& e);
+
+    /**
+     * D-Bus bus object.
+     */
+    sdbusplus::bus_t& bus;
+};
+
+} // namespace phosphor::power::sequencer