Clarence Williams III, who played the cool undercover cop Linc Hayes on the counterculture series “The Mod Squad” and Prince’s father in “Purple Rain,” has died. He was 81. Williams died Friday at his home in Los Angeles after a battle with colon cancer, his manager Allan Mindel said Sunday. A native of New York, Williams career spanned over five decades in theater, television and film. He was born into a creative family in 1939 and raised by his musical grandparents. He got his acting start on Broadway. His breakout role would come with “The Mod Squad,” which he led with Peggy Lipton and Michael Cole during its run on ABC.