LTC4245_GPIO
gpio_curr = (data->cregs[LTC4245_GPIO] & 0xc0) >> 6;
gpio_reg = (data->cregs[LTC4245_GPIO] & 0x3f) | ((gpio_next + 1) << 6);
i2c_smbus_write_byte_data(client, LTC4245_GPIO, gpio_reg);
data->cregs[LTC4245_GPIO] = gpio_reg;