mcpgpio_read
error = mcpgpio_read(sc, bank, REG_GPIO, &data);
error = mcpgpio_read(sc, bank, REG_OLAT, &data);
if ((error = mcpgpio_read(sc, bank, REG_IODIR, &iodir)) != 0 ||
(error = mcpgpio_read(sc, bank, REG_IPOL, &ipol)) != 0 ||
(error = mcpgpio_read(sc, bank, REG_GPPU, &gppu)) != 0) {