diff --git a/power-supply/main.cpp b/power-supply/main.cpp
index eb3f9ed..e36bd24 100644
--- a/power-supply/main.cpp
+++ b/power-supply/main.cpp
@@ -56,13 +56,16 @@
         return -4;
     }
 
+    auto bus = sdbusplus::bus::new_default();
+
     auto objname = "power_supply" + instnum;
     auto instance = std::stoul(instnum);
     auto psuDevice = std::make_unique<psu::PowerSupply>(objname,
                                                         std::move(instance),
                                                         std::move(objpath),
-                                                        std::move(invpath));
-    auto bus = sdbusplus::bus::new_default();
+                                                        std::move(invpath),
+                                                        bus);
+
     sd_event* events = nullptr;
 
     auto r = sd_event_default(&events);
@@ -81,6 +84,14 @@
 
     // TODO: Use inventory path to subscribe to signal change for power supply presence.
 
+    //Attach the event object to the bus object so we can
+    //handle both sd_events (for the timers) and dbus signals.
+    bus.attach_event(eventPtr.get(), SD_EVENT_PRIORITY_NORMAL);
+
+    // TODO: Get power state on startup.
+    // TODO: Get presence state on startup and subscribe to presence changes.
+    // TODO - set to vinUVFault to false on presence change & start of poweron
+    // TODO - set readFailLogged to false on presence change and start of poweron
     auto pollInterval = std::chrono::milliseconds(1000);
     DeviceMonitor mainloop(std::move(psuDevice), eventPtr, pollInterval);
     mainloop.run();
diff --git a/power-supply/power_supply.cpp b/power-supply/power_supply.cpp
index e9f5d6b..8dd4c3e 100644
--- a/power-supply/power_supply.cpp
+++ b/power-supply/power_supply.cpp
@@ -13,7 +13,20 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+#include <phosphor-logging/log.hpp>
+#include <phosphor-logging/elog.hpp>
+#include <xyz/openbmc_project/Sensor/Device/error.hpp>
+#include <xyz/openbmc_project/Control/Device/error.hpp>
+#include <xyz/openbmc_project/Power/Fault/error.hpp>
+#include "elog-errors.hpp"
 #include "power_supply.hpp"
+#include "pmbus.hpp"
+#include "utility.hpp"
+
+using namespace phosphor::logging;
+using namespace sdbusplus::xyz::openbmc_project::Control::Device::Error;
+using namespace sdbusplus::xyz::openbmc_project::Sensor::Device::Error;
+using namespace sdbusplus::xyz::openbmc_project::Power::Fault::Error;
 
 namespace witherspoon
 {
@@ -22,15 +35,56 @@
 namespace psu
 {
 
+
 void PowerSupply::analyze()
 {
-    //TODO analyze() needs to be implemented in this class.
+    using namespace witherspoon::pmbus;
+
+    try
+    {
+        auto curUVFault = pmbusIntf.readBit(VIN_UV_FAULT, Type::Hwmon);
+        //TODO: 3 consecutive reads should be performed.
+        // If 3 consecutive reads are seen, log the fault.
+        // Driver gives cached value, read once a second.
+        // increment for fault on, decrement for fault off, to deglitch.
+        // If count reaches 3, we have fault. If count reaches 0, fault is
+        // cleared.
+
+        //TODO: INPUT FAULT or WARNING bit to check from STATUS_WORD
+        // pmbus-core update to read high byte of STATUS_WORD?
+
+        if ((curUVFault != vinUVFault) || inputFault)
+        {
+            if (curUVFault)
+            {
+                //FIXME - metadata
+                report<PowerSupplyUnderVoltageFault>();
+                vinUVFault = true;
+            }
+            else
+            {
+                log<level::INFO>("VIN_UV_FAULT cleared");
+                vinUVFault = false;
+            }
+        }
+    }
+    catch (ReadFailure& e)
+    {
+        if (!readFailLogged)
+        {
+            commit<ReadFailure>();
+            readFailLogged = true;
+            // TODO - Need to reset that to false at start of power on, or
+            // presence change.
+        }
+    }
+
     return;
 }
 
 void PowerSupply::clearFaults()
 {
-    //TODO
+    //TODO - Clear faults at pre-poweron.
     return;
 }
 
diff --git a/power-supply/power_supply.hpp b/power-supply/power_supply.hpp
index 4249024..43489d2 100644
--- a/power-supply/power_supply.hpp
+++ b/power-supply/power_supply.hpp
@@ -1,5 +1,6 @@
 #pragma once
 #include "device.hpp"
+#include "pmbus.hpp"
 
 namespace witherspoon
 {
@@ -29,10 +30,14 @@
          * @param[in] inst - the device instance
          * @param[in] objpath - the path to monitor
          * @param[in] invpath - the inventory path to use
+         * @param[in] bus - D-Bus bus object
          */
         PowerSupply(const std::string& name, size_t inst,
-                    const std::string& objpath, const std::string& invpath)
-            : Device(name, inst), monitorPath(objpath), inventoryPath(invpath)
+                    const std::string& objpath,
+                    const std::string& invpath,
+                    sdbusplus::bus::bus& bus)
+            : Device(name, inst), monitorPath(objpath), inventoryPath(invpath),
+            bus(bus), pmbusIntf(objpath)
         {
         }
 
@@ -65,6 +70,39 @@
          * The D-Bus path to use for this power supply's inventory status.
          */
         std::string inventoryPath;
+
+        /** @brief Connection for sdbusplus bus */
+        sdbusplus::bus::bus& bus;
+
+        /**
+         * @brief Pointer to the PMBus interface
+         *
+         * Used to read out of or write to the /sysfs tree(s) containing files
+         * that a device driver monitors the PMBus interface to the power
+         * supplies.
+         */
+        witherspoon::pmbus::PMBus pmbusIntf;
+
+        /**
+         * @brief Has a PMBus read failure already been logged?
+         */
+        bool readFailLogged = false;
+
+        /**
+         * @brief Set to true when a VIN UV fault has been detected
+         *
+         * This is the VIN_UV_FAULT bit in the low byte from the STATUS_WORD
+         * command response.
+         */
+        bool vinUVFault = false;
+
+        /**
+         * @brief Set to true when an input fault or warning is detected
+         *
+         * This is the "INPUT FAULT OR WARNING" bit in the high byte from the
+         * STATUS_WORD command response.
+         */
+        bool inputFault = false;
 };
 
 }