WM8753 (also the Wolfson Codec) is the "sound card" chip in the Neo1973 audio subsystem. It has a stereo ADC for recording and a stereo DAC for playback, plus a mono "voice" DAC.
It's connected to the S3C2410 IIS interface for PCM data, and to the S3C2410 I2C interface for control. (Is the "voice" interface unconnected?). The stereo output ("Audio Out": LOUT1 and ROUT1) is connected to LM4857 stereo input (LIN and RIN) for amplification. MONO1 and MONO2 form "GSM Line Out"; RXP and RXN form "GSM Line In". MIC1 is "Headset Mic", and MIC2 is "Call Mic".
The following output pins are not connected: LOUT2 and ROUT2, OUT3, OUT4. The following input pins are not connected: LINE1, LINE2.
There are several sources connected via switches that can cut each source out:
- "Left Mixer Left" and "Right Mixer Right Playback Switch" connect the stereo DAC for stereo mixing.
- "Mono Mixer Left" and "Mono Mixer Right Playback Switch" connect the stereo DAC for mono mixing.
- XXX bypass, sidetone, voice
- Off: all off.
- GSM Handset: only "Headset Mic" off.
- GSM Headset: only "Call Mic" off.
- GSM Bluetooth: only "Line In" and "Line Out" on.
- Speakers: only "Audio Out" on.
- Headphones: only "Audio Out" on.
- Capture Handset: only "Call Mic" on.
- Capture Headset: only "Headset Mic" on.
- Capture Bluetooth: all off.
- The WM8753 data sheet (PDF)
- asoc-* at OpenMoko kernel patches