4 files changed, 22 insertions, 2 deletions
diff --git a/host/lib/usrp/e100/clock_ctrl.cpp b/host/lib/usrp/e100/clock_ctrl.cpp
index 0eb9eef8e..1dd55049b 100644
--- a/host/lib/usrp/e100/clock_ctrl.cpp
+++ b/host/lib/usrp/e100/clock_ctrl.cpp
@@ -432,6 +432,16 @@ public:
         this->latch_regs();
     }
 
+    bool get_locked(void){
+        static const boost::uint8_t addr = 0x01F;
+        boost::uint32_t reg = _iface->read_spi(
+            UE_SPI_SS_AD9522, spi_config_t::EDGE_RISE,
+            _ad9522_regs.get_read_reg(addr), 24
+        );
+        _ad9522_regs.set_reg(addr, reg);
+        return _ad9522_regs.digital_lock_detect != 0;
+    }
+
 private:
     spi_iface::sptr _iface;
     const bool _dboard_clocks_diff;
diff --git a/host/lib/usrp/e100/clock_ctrl.hpp b/host/lib/usrp/e100/clock_ctrl.hpp
index 538ea65d8..803265556 100644
--- a/host/lib/usrp/e100/clock_ctrl.hpp
+++ b/host/lib/usrp/e100/clock_ctrl.hpp
@@ -119,6 +119,9 @@ public:
      */
     virtual void use_auto_ref(void) = 0;
 
+    //! Is the reference locked?
+    virtual bool get_locked(void) = 0;
+
 };
 
 #endif /* INCLUDED_USRP_E100_CLOCK_CTRL_HPP */
diff --git a/host/lib/usrp/e100/e100_impl.cpp b/host/lib/usrp/e100/e100_impl.cpp
index b80ee0836..b988de9a1 100644
--- a/host/lib/usrp/e100/e100_impl.cpp
+++ b/host/lib/usrp/e100/e100_impl.cpp
@@ -226,8 +226,8 @@ e100_impl::e100_impl(const uhd::device_addr_t &device_addr){
     ////////////////////////////////////////////////////////////////////
     // and do the misc mboard sensors
     ////////////////////////////////////////////////////////////////////
-    //none for now...
-    _tree->create<int>(mb_path / "sensors"); //phony property so this dir exists
+    _tree->create<sensor_value_t>(mb_path / "sensors/ref_locked")
+        .publish(boost::bind(&e100_impl::get_ref_locked, this));
 
     ////////////////////////////////////////////////////////////////////
     // create frontend control objects
@@ -406,3 +406,8 @@ void e100_impl::update_clock_source(const std::string &source){
     else if (source == "external") _clock_ctrl->use_external_ref();
     else throw uhd::runtime_error("unhandled clock configuration reference source: " + source);
 }
+
+sensor_value_t e100_impl::get_ref_locked(void){
+    const bool lock = _clock_ctrl->get_locked();
+    return sensor_value_t("Ref", lock, "locked", "unlocked");
+}
diff --git a/host/lib/usrp/e100/e100_impl.hpp b/host/lib/usrp/e100/e100_impl.hpp
index a15197545..99c8481e3 100644
--- a/host/lib/usrp/e100/e100_impl.hpp
+++ b/host/lib/usrp/e100/e100_impl.hpp
@@ -31,6 +31,7 @@
 #include <uhd/usrp/subdev_spec.hpp>
 #include <uhd/usrp/dboard_eeprom.hpp>
 #include <uhd/usrp/mboard_eeprom.hpp>
+#include <uhd/types/sensors.hpp>
 #include <uhd/types/otw_type.hpp>
 #include <uhd/types/clock_config.hpp>
 #include <uhd/types/stream_cmd.hpp>
@@ -124,6 +125,7 @@ private:
     void update_rx_subdev_spec(const uhd::usrp::subdev_spec_t &);
     void update_tx_subdev_spec(const uhd::usrp::subdev_spec_t &);
     void update_clock_source(const std::string &);
+    uhd::sensor_value_t get_ref_locked(void);
 
 };