How can I access the MCP3008 ADC chip with linux spidev?
It's got a SPI based interface, correct?  If so, then you should be able to just write a userspace driver to interface with the chip.  Did you look at Interfacing an SPI ADC (MCP3008) chip to the Raspberry Pi using C++ (spidev)? 

If your hardware has SPI then your kernel should have a SPI driver loaded, and /dev/spidev* should be populated.