pseq: Create UCD90xDevice class

Create the UCD90xDevice class in the phosphor-power-sequencer
application.

This is a base class for the UCD90x family of power sequencer devices.

Tested:
* Performed the following tests on Rainier and Everest systems
  * MFR_STATUS value obtained successfully
  * Verified error paths and exceptions thrown

Change-Id: I430ffb95d96e228ce0245ae1c9cb63db72d590c5
Signed-off-by: Shawn McCarney <shawnmm@us.ibm.com>
diff --git a/phosphor-power-sequencer/src/ucd90x_device.hpp b/phosphor-power-sequencer/src/ucd90x_device.hpp
new file mode 100644
index 0000000..f5044c8
--- /dev/null
+++ b/phosphor-power-sequencer/src/ucd90x_device.hpp
@@ -0,0 +1,96 @@
+/**
+ * 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_driver_device.hpp"
+#include "rail.hpp"
+#include "services.hpp"
+
+#include <cstdint>
+#include <map>
+#include <memory>
+#include <string>
+#include <utility>
+#include <vector>
+
+namespace phosphor::power::sequencer
+{
+
+/**
+ * @class UCD90xDevice
+ *
+ * PMBusDriverDevice sub-class for the UCD90X family of power sequencer devices.
+ *
+ * These devices share a common device driver.
+ */
+class UCD90xDevice : public PMBusDriverDevice
+{
+  public:
+    // Specify which compiler-generated methods we want
+    UCD90xDevice() = delete;
+    UCD90xDevice(const UCD90xDevice&) = delete;
+    UCD90xDevice(UCD90xDevice&&) = delete;
+    UCD90xDevice& operator=(const UCD90xDevice&) = delete;
+    UCD90xDevice& operator=(UCD90xDevice&&) = delete;
+    virtual ~UCD90xDevice() = default;
+
+    /**
+     * Constructor.
+     *
+     * @param name Device name
+     * @param rails Voltage rails that are enabled and monitored by this device
+     * @param services System services like hardware presence and the journal
+     * @param bus I2C bus for the device
+     * @param address I2C address for the device
+     */
+    explicit UCD90xDevice(const std::string& name,
+                          std::vector<std::unique_ptr<Rail>> rails,
+                          Services& services, uint8_t bus, uint16_t address) :
+        PMBusDriverDevice(name, std::move(rails), services, bus, address,
+                          driverName)
+    {}
+
+    /**
+     * Returns the value of the PMBus MFR_STATUS command.
+     *
+     * This is a manufacturer-specific command that replaces the standard
+     * STATUS_MFR_SPECIFIC command on UCD90x devices.
+     *
+     * The returned value is in host-endian order.
+     *
+     * Note that the UCD90x documentation states that this is a paged command.
+     * This means that the PMBus PAGE should be set, and some of the bits in the
+     * command value are page-specific.  However, the current device driver only
+     * provides a single file in sysfs, and the driver always sets the PAGE to
+     * 0.  Thus, the bits that are page-specific in the returned value are
+     * always for PAGE 0.
+     *
+     * Throws an exception if the value could not be obtained.
+     *
+     * @return MFR_STATUS value
+     */
+    virtual uint64_t getMfrStatus();
+
+    constexpr static std::string driverName{"ucd9000"};
+
+  protected:
+    /** @copydoc PMBusDriverDevice::storePgoodFaultDebugData() */
+    virtual void storePgoodFaultDebugData(
+        Services& services, const std::vector<int>& gpioValues,
+        std::map<std::string, std::string>& additionalData) override;
+};
+
+} // namespace phosphor::power::sequencer