1 files changed, 110 insertions, 0 deletions
diff --git a/presence/tach.hpp b/presence/tach.hpp
new file mode 100644
index 0000000..4f02521
--- /dev/null
+++ b/presence/tach.hpp
@@ -0,0 +1,110 @@
+#pragma once
+
+#include <sdbusplus/message.hpp>
+#include <sdbusplus/bus/match.hpp>
+#include <string>
+#include <vector>
+#include "psensor.hpp"
+#include "sdbusplus.hpp"
+
+namespace phosphor
+{
+namespace fan
+{
+namespace presence
+{
+class RedundancyPolicy;
+
+/**
+ * @class Tach
+ * @brief Fan tach sensor presence implementation.
+ *
+ * The Tach class uses one or more tach speed indicators
+ * to determine presence state.
+ */
+class Tach : public PresenceSensor
+{
+    public:
+        /**
+         * @brief
+         *
+         * Cannot move or copy due to this ptr as context
+         * for sdbus callbacks.
+         */
+        Tach() = delete;
+        Tach(const Tach&) = delete;
+        Tach& operator=(const Tach&) = delete;
+        Tach(Tach&&) = delete;
+        Tach& operator=(Tach&&) = delete;
+        ~Tach() = default;
+
+        /**
+         * @brief ctor
+         *
+         * @param[in] sensors - Fan tach sensors for this psensor.
+         */
+        Tach(const std::vector<std::string>& sensors);
+
+        /**
+         * @brief start
+         *
+         * Register for dbus signal callbacks on fan
+         * tach sensor change.  Query initial tach speeds.
+         *
+         * @return The current sensor state.
+         */
+        bool start() override;
+
+        /**
+         * @brief stop
+         *
+         * De-register dbus signal callbacks.
+         */
+        void stop() override;
+
+        /**
+         * @brief Check the sensor.
+         *
+         * Query the tach speeds.
+         */
+        bool present() override;
+
+    private :
+        /**
+         * @brief Get the policy associated with this sensor.
+         */
+        virtual RedundancyPolicy& getPolicy() = 0;
+
+        /**
+         * @brief Properties changed handler for tach sensor updates.
+         *
+         * @param[in] sensor - The sensor that changed.
+         * @param[in] props - The properties that changed.
+         */
+        void propertiesChanged(
+            size_t sensor,
+            const phosphor::fan::util::Properties<int64_t>& props);
+
+        /**
+         * @brief Properties changed handler for tach sensor updates.
+         *
+         * @param[in] sensor - The sensor that changed.
+         * @param[in] msg - The sdbusplus signal message.
+         */
+        void propertiesChanged(
+            size_t sensor,
+            sdbusplus::message::message& msg);
+
+        /** @brief array of tach sensors dbus matches, and tach values. */
+        std::vector<std::tuple<
+            std::string,
+            std::unique_ptr<sdbusplus::bus::match::match>,
+            int64_t>> state;
+
+        /** The current state of the sensor. */
+        bool currentState;
+};
+
+} // namespace presence
+} // namespace fan
+} // namespace phosphor