Assuming you stay Intrastate in California and are not hauling any type of hazardous materials:
You may drive up to 12 hours unless you are driving a tank vehicle with a capacity of 500 gallons or more and transporting flammables.
You may not drive after having been on duty for more than 80 hours in any 8 day period.
If you are hauling hazmat, driving interstate, etc then you are governed by the federal regs:
PART 395 Hos Regs