--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/aud-c139/headset.src	Tue Apr 05 06:22:50 2022 +0000
@@ -0,0 +1,24 @@
+# C139 headset audio mode, reconstructed from register readings
+# collected in freecalypso-reveng repository, compal/audio directory
+
+mic headset {
+	gain 9		# read out via omr in active call state
+	output-bias 0	# C139 uses 2.0V
+}
+
+# C139 fw applies complex volume control: it messes with PGA settings,
+# and in headset mode it also applies a FIR filter that produces a 6 dB
+# digital gain without any frequency curve transformation.
+#
+# For FreeCalypso, given how far we are from actually using the headset jack
+# on C139 for its headset function (as opposed to the serial port),
+# we are going to start with PGA at 0 and no weird FIR.
+
+speaker headset {
+	gain 0
+}
+
+sidetone -23		# readout of VBUCTRL from official fw
+
+# C139 AEC config for headset mode
+aec-new 2 1 0x14 0x4CCC 0x59AD 0x7500 0 0x1000 0x1000 0 4 0x20