Success: Two-way phone call with Treo 650 in Linux

Now that I have a VOIP account that can make unmetered calls to mobiles I decided to try having a play with getting two-way phone calls working from Linux on the Treo 650. I turned on the phone part in Palm OS, booted this kernel and reset the power on the gsm module with:

echo 0 > /sys/devices/platform/palmt650-pm-gsm/power_on
echo 1 > /sys/devices/platform/palmt650-pm-gsm/power_on
echo 1 > /sys/devices/platform/palmt650-pm-gsm/wake

I then fired open minicom and opened /dev/ttyS0 at baud 460800 without flow control. I then connected the modem to the network and entered my subsidy unlock pin:

AT+CFUN=1
AT+CPIN="xxxxxxxxx"

Once connected, I called my phone via VOIP and then answered with the ATA command:

RING
RING

ATA
OK

At that point I opened up a few terminal windows and started fiddling with ALSA. I first started playing some white noise so I could heer when I started transmitting:

cat /dev/urandom > /dev/dsp

I discovered you can divert PCM to be transmitted by the phone using:

      Master Mono: Enable, set transmit volume
              PCM: Enable, set PCM volume
PCM Play to Phone: Enable to route PCM signal to the phone module

After some more fiddling I routed the microphone to the phone. The labeling of the Mic controls in the ALSA driver is rather strange but here are the key settings:

      Master Mono: Enable, set transmit volume
Mic Select Source: mic1=handset, mic2=headset
            Mic 2: Selected mic volume
   Mic 1 to phone: Enable/disable handset mic 
   Mic 2 to phone: Enable/disable oheadset mic
   Mic 20dB Boost: Useful in speakerphone mode, you can talk from quite a distance.

Mic 1: [irrelevant?]
Mic select:  [irrelevant?]

After that I managed to get the incoming audio going out the handset earpiece with these settings:

         Master: Enable, earpiece volume
Master Left Inv: Enable
          Phone: Seems you don't need to unmute, but need to set volume.
Phone to Master: Enable
            Aux: Set a high volume (weird stuff happens if low)
    Out3 LR Mux: Master Mix (mislabeled, it's actually out2)

I've made an ALSA state file for working two-way phone audio with the handset.

Hello! Hello?!

Well there's been much progress. I've basically finished off the kernel driver aside from waking the CPU from suspend upon an incoming call. Also adding basic BCM2132 to gsmd turned out to be a fairly simple procedure aside from some strangenesses of the platform. See the gsmd list for my patches. So now we can make and receive calls and SMS with the only remaining problem being routing of audio.

I've setup a skeleton SoC audio driver. This is enough after some fiddling with alsamixer to at least be able to hear what the other person says but outgoing sound doesn't work. The diagram to the left shows how I think things are wired up and should be of use to anyone trying to understand the huge number of alsamixer controls. At the moment I'm trying to get OE building an OpenMoko image with MACHINE=palmt650. :-)