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 "hi-fi" data, and to the S3C2410 I2C interface for control. The PCM "voice" input and output is connected to the Bluetooth chip. 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.
http://wolfson.co.uk/uploads/images/en/WM8753_BlockDiagram.gif
There are several sources connected via switches that can cut each source out:
From: Joerg Reisenweber <joerg@openmoko.org> To: openmoko-devel@lists.openmoko.org Date: Thu, 12 Jun 2008 15:48:58 +0200 LOUT2/ROUT2 is handset earpiece (aka receiver). LOUT1/ROUT1 is routing to external amp, which there is switching between headset-stereo and device-speaker-mono(GTA02)/stereo(GTA01) via cpu-GPIO[HP_IN]. (what also is a function I expect to see in alsa-driver of our "OEM-card", but surely NOT in WM8753-alsa-driver) NC: OUT3 OUT4 MONO1, MONO2: differential output routing to mic analog in of GSM and while I'm writing... MIC2,MIC2N: diff. input from handset mic MIC1,MIC1N: "differential" Input from headset (ring3 jack, MIC1N:GND via 100N) RXP,RXN: diff. input from GSM analog "earpiece" output ACOP->AIN via 100N LINE1, LINE2: to testpoint H-TP3001/2, NC VXD: digital PCM to BT (mono only?) DACDAT, ADCDAT: to cpu via IIS