OptionalbusyThe line an SX126x's BUSY pin is on. The SX127x has no BUSY pin.
The GPIO chip the lines are on, /dev/gpiochip0 for a Raspberry Pi's header.
The line the module's reset pin is on, the BCM GPIO number on a Raspberry Pi.
The SPI device file, one per chip select, such as /dev/spidev0.0.
OptionalspiThe SPI clock in hertz, 2 MHz when omitted.
Where a radio module is wired on a Linux board.