Passport only or passport AND Visa to visit Shanghai for 10 days?

My son teaches English at one of the colleges in China and I am going to visit him for 12 days at the end of August and the beginning of September, respectively, so I can be there for the birth of my grandchild. I do not know what paperwork, other than a Passport, that I will need to go there. Can you please help me with the details of the required items that are needed and where I must go to obtain these?