uhd: Add reference power level API to multi_usrp and radio_control

This adds the following API calls:

- multi_usrp::has_{rx,tx}_power_reference()
- multi_usrp::set_{rx,tx}_power_reference()
- multi_usrp::get_{rx,tx}_power_reference()
- radio_control::has_{rx,tx}_power_reference()
- radio_control::set_{rx,tx}_power_reference()
- radio_control::get_{rx,tx}_power_reference()

It also adds a manual page explaining the philosophy of the API.

Note that this does not actually add this feature to any device
implementation. Calling the new API calls will thus result in
`uhd::not_implemented_error` exceptions being thrown. This commit is to
lock down the API and ABI.

1 files changed, 36 insertions, 0 deletions

diff --git a/host/lib/rfnoc/radio_control_impl.cpp b/host/lib/rfnoc/radio_control_impl.cpp
index 4f1246e5c..e34a9b430 100644
--- a/host/lib/rfnoc/radio_control_impl.cpp
+++ b/host/lib/rfnoc/radio_control_impl.cpp
@@ -404,6 +404,28 @@ double radio_control_impl::set_rx_gain(
     return set_rx_gain(gain, chan);
 }
 
+bool radio_control_impl::has_rx_power_reference(const size_t)
+{
+    return false;
+}
+
+bool radio_control_impl::has_tx_power_reference(const size_t)
+{
+    return false;
+}
+
+void radio_control_impl::set_rx_power_reference(const double, const size_t)
+{
+    throw uhd::not_implemented_error(
+        "set_rx_power_reference() is not supported on this radio!");
+}
+
+void radio_control_impl::set_tx_power_reference(const double, const size_t)
+{
+    throw uhd::not_implemented_error(
+        "set_tx_power_reference() is not supported on this radio!");
+}
+
 void radio_control_impl::set_rx_agc(const bool, const size_t)
 {
     throw uhd::not_implemented_error("set_rx_agc() is not supported on this radio!");
@@ -575,6 +597,20 @@ uhd::meta_range_t radio_control_impl::get_rx_bandwidth_range(size_t chan) const
     return result;
 }
 
+double radio_control_impl::get_rx_power_reference(const size_t)
+{
+    throw uhd::not_implemented_error(
+        "get_rx_power_reference() is not supported on this radio!");
+    return 0.0;
+}
+
+double radio_control_impl::get_tx_power_reference(const size_t)
+{
+    throw uhd::not_implemented_error(
+        "get_tx_power_reference() is not supported on this radio!");
+    return 0.0;
+}
+
 /******************************************************************************
  * LO Default API
  *****************************************************************************/