The premise of the question is incorrect. Hinduism is most certainly and very much prevalent in South India, along with Islam, Christianity, and many other religions. There is no such thing as Dravidianism. If there was such a thing in ancient times, it is a highly debated and contentious issue. Genetics and many other modern tools seem to suggest that these are constructs - just like race. So if the question is with reference to religion- there is no religion called Dravidianism. If it is a racial question- I propose that it is an incorrect premise to construct racial identities.
EDIT: (Addition)
Many of the greatest "revivalists" and thinkers of Hinduism (although the term Hinduism is very broad- i use it here in the conventional sense) have come from South India (South India- again in conventional sense). Three of the most well known scholars/thinkers were Shankaracharya, Ramanuja and Madhavacharya.
Epics such as the Ramayana have been re-interpreted and re-told in South Indian Languages such as Kamban's version of Ramayana. Also, Shaivism and other forms of Hinduism has had rich literary inputs from all languages. To see Tamil literature check this. The other (primary) languages in south India are Kannada, Malayalam, and Telugu. A search will throw up many results, but it is too vast to cover in an SE answer.