remove gain_mode getter/setter where not used

lib/fcd/fcd_source.cc

@@ -206,16 +206,6 @@ osmosdr::gain_range_t fcd_source::get_gain_range( const std::string & name, size
   return get_gain_range( chan );
 }
 
-bool fcd_source::set_gain_mode( bool automatic, size_t chan )
-{
-  return get_gain_mode(chan);
-}
-
-bool fcd_source::get_gain_mode( size_t chan )
-{
-  return true;
-}
-
 double fcd_source::set_gain( double gain, size_t chan )
 {
   _src->set_lna_gain(gain);

lib/fcd/fcd_source.h

@@ -65,8 +65,6 @@ public:
   std::vector<std::string> get_gain_names( size_t chan = 0 );
   osmosdr::gain_range_t get_gain_range( size_t chan = 0 );
   osmosdr::gain_range_t get_gain_range( const std::string & name, size_t chan = 0 );
-  bool set_gain_mode( bool automatic, size_t chan = 0 );
-  bool get_gain_mode( size_t chan = 0 );
   double set_gain( double gain, size_t chan = 0 );
   double set_gain( double gain, const std::string & name, size_t chan = 0 );
   double get_gain( size_t chan = 0 );

lib/file/file_source_c.cc

@@ -183,16 +183,6 @@ osmosdr::gain_range_t file_source_c::get_gain_range( const std::string & name, s
   return get_gain_range( chan );
 }
 
-bool file_source_c::set_gain_mode( bool automatic, size_t chan )
-{
-  return get_gain_mode(chan);
-}
-
-bool file_source_c::get_gain_mode( size_t chan )
-{
-  return true;
-}
-
 double file_source_c::set_gain( double gain, size_t chan )
 {
   return get_gain(chan);

lib/file/file_source_c.h

@@ -63,8 +63,6 @@ public:
   std::vector<std::string> get_gain_names( size_t chan = 0 );
   osmosdr::gain_range_t get_gain_range( size_t chan = 0 );
   osmosdr::gain_range_t get_gain_range( const std::string & name, size_t chan = 0 );
-  bool set_gain_mode( bool automatic, size_t chan = 0 );
-  bool get_gain_mode( size_t chan = 0 );
   double set_gain( double gain, size_t chan = 0 );
   double set_gain( double gain, const std::string & name, size_t chan = 0 );
   double get_gain( size_t chan = 0 );

lib/osmosdr_src_iface.h

@@ -130,14 +130,14 @@ public:
    * \param chan the channel index 0 to N-1
    * \return the actual gain mode
    */
-  virtual bool set_gain_mode( bool automatic, size_t chan = 0 ) = 0;
+  virtual bool set_gain_mode( bool automatic, size_t chan = 0 ) { return false; }
 
   /*!
    * Get the gain mode selected for the underlying radio hardware.
    * \param chan the channel index 0 to N-1
    * \return the actual gain mode (true means automatic gain mode)
    */
-  virtual bool get_gain_mode( size_t chan = 0 ) = 0;
+  virtual bool get_gain_mode( size_t chan = 0 ) { return false; }
 
   /*!
    * Set the gain for the underlying radio hardware.

lib/uhd/uhd_source_c.cc

@@ -229,16 +229,6 @@ osmosdr::gain_range_t uhd_source_c::get_gain_range( const std::string & name, si
   return range;
 }
 
-bool uhd_source_c::set_gain_mode( bool automatic, size_t chan )
-{
-  return get_gain_mode(chan);
-}
-
-bool uhd_source_c::get_gain_mode( size_t chan )
-{
-  return true;
-}
-
 double uhd_source_c::set_gain( double gain, size_t chan )
 {
   _src->set_gain(gain, chan);

lib/uhd/uhd_source_c.h

@@ -65,8 +65,6 @@ public:
   std::vector<std::string> get_gain_names( size_t chan = 0 );
   osmosdr::gain_range_t get_gain_range( size_t chan = 0 );
   osmosdr::gain_range_t get_gain_range( const std::string & name, size_t chan = 0 );
-  bool set_gain_mode( bool automatic, size_t chan = 0 );
-  bool get_gain_mode( size_t chan = 0 );
   double set_gain( double gain, size_t chan = 0 );
   double set_gain( double gain, const std::string & name, size_t chan = 0 );
   double get_gain( size_t chan = 0 );