MAX_GPIO_REG
gpio = I2C_READ(sc, MAX_GPIO_REG(pin));
I2C_WRITE(sc, MAX_GPIO_REG(pin), gpio);
gpio = I2C_READ(sc, MAX_GPIO_REG(gpin->pin_num));
gpio = I2C_READ(sc, MAX_GPIO_REG(gpin->pin_num));
I2C_READ(sc, MAX_GPIO_REG(gpin->pin_num)), gpio);
I2C_WRITE(sc, MAX_GPIO_REG(gpin->pin_num), gpio);