This news from California: A Cambodian immigrant is suing two Silicon Valley companies, claiming they fired him for refusing to do extra work at home for below the minimum wage. The lawsuit follows a state Labor Department decision in July to investigate whether Silicon Valley high-tech companies pay Asian immigrants low wages to assemble electronic parts at home. Kamsan Mao alleged that his former employer, Top Line Electronics in San Jose, forced him to work at home at night and on weekends after his daily eight-hour shifts. Mao says he was paid less than minimum wage, sometimes as little as $5 for three hours of labor, as he built and repaired power supplies that go into computers.