embedded linux audio

Hi all, Iam trying to run linphone (opensource IP phone) in powerPC based xilinx development board. The board contains a Audio Codec chip LM4550 and speaker, Mic i/os. I also have xilinx board based AC97 audio drivers (not for linux). I plan to modify the low level IO functions used in drivers with linux IO functions to make it work under embedded linux (monta vista Linux). I dont know how can I make changes in linphone open source application so that it uses my device drivers for audio functions. Since I use linux2.4.xx I feel I can use only OSS drivers. How can I specify in my device driver. Could anyone tell how can I go about, Prakash