hdf_config/hdf_test/spi_test_config.hcs

root {
    spi_test {
        module = "spi_test";
        match_attr = "SPI_TEST";
        bus = 0;
        cs = 0;
        len = 8;
        wbuf = [0xa1, 0xb2, 0xc3, 0xd4, 0xe5, 0xf6, 0x78, 0x90];
    }
}