float ltc6904_get_selected_frequency(LTC6904_OSCILLATOR_t *self);
ltc6904_get_selected_frequency returns the selected oscillator frequency in hertz, derived from the internal octave and DAC select bits. This is the datasheet "true" oscillator frequency nearest to the frequency requested by ltc6904_set_frequency.
ltc6904_get_selected_frequency returns a standard status code.
ltc6904_get_selected_frequency is thread-safe if the transport member in self is thread-safe. Typically, for SPI and I2C transports, you ensure thread safety by associating a mutex with the bus used by the transport.