/// in some header
typedef ... hm2_spi_setup_function;
typedef ... hm2_spi_force_write_function;
typedef ... hm2_spi_prepare_tram_write_function;
typedef ... hm2_spi_process_tram_read_function;
struct hm2_spi_module {
    char name[16];
    hm2_spi_setup_function setup;
    hm2_spi_force_write_function force_write;
    hm2_spi_prepare_tram_write_function prepare_tram_write;
    hm2_spi_process_tram_read_function process_tram_read;
};

/// in some driver
static struct hm2_spi_module bogoboard_submodule = {
    "bogoboard",
    bogoboard_setup,
    bogoboard_force_write,
    bogoboard_prepare_tram_write,
    bogoboard_process_tram_read
};

rtapi_app_main() {
    return hm2_register_spi_subdriver( &bogoboard_submodule );
}


/// in some hal file
loadrt hm2_pic config="...., spi=bogoboard.bogoboard.cleverboard"