need help on SPI (atmega32u4 <-> MCP2515)

I have the following custom board (see attachement), can anyone advise how do I interface with MCP2515?
Issue is that to talk to SPI slave I have to set CS to LOW, but according to the schema it is not connected to atmega32u4.

Ok, got it working. I miss read the schematics, SS pin was wired to PB0 on atmega.