WM8753 (also the Wolfson Codec) is the "sound card" chip in the Neo1973 audio subsystem.
It's connected to the S3C2410 IIS interface for PCM data, and to the S3C2410 I2C interface for control. The stereo output (LOUT1 and ROUT1) is connected to LM4857 stereo input (LIN and RIN) for amplification.
There are several sources connected via switches that can cut each source out: