VSC_ADDR_OFFSET
ret = vsc_read(dev, VSC_ADDR_OFFSET, &val);
ret = vsc_read(dev, VSC_ADDR_OFFSET, &flag);
ret = vsc_write(dev, VSC_ADDR_OFFSET, address);
ret = vsc_write(dev, VSC_ADDR_OFFSET, address);
ret = vsc_read(dev, VSC_ADDR_OFFSET, next_read_addr);