mcpgpio_spi_write
.write = mcpgpio_spi_write,
error = mcpgpio_spi_write(sc, 0, REG_IOCON, sc->sc_iocon);
error = mcpgpio_spi_write(sc, 0, REGADDR_BANK0(0, REG_IOCON),
error = mcpgpio_spi_write(sc, 1,