Here's an output of running a serial BT module connected to my C1K via external rs232 transceiver:
# cat /proc/tty/driver/serial
serinfo:1.0 driver:5.05c revision:Jun 28 2005
0: uart:PXA UART port:F8100000 irq:22 baud:460800 tx:5675 rx:12368 RTS|CTS|DTR|DSR|CD|RI
1: uart:PXA UART port:F8200000 irq:21 tx:0 rx:0
2: uart:PXA UART port:F8700000 irq:20 tx:0 rx:0
3: uart:16C950/954 port:F60003F8 irq:135 tx:0 rx:0
# btctl -v         Â
bt0 Â Â 00:10:60:a2:cb:8e
    Name: "zaurus"
    Class: 0xB2010C, Computer (Laptop) [Networking,Object Transfer,Audio,Information]
    Scan Mode: discoverable, connectable
    Security: service pair [-auth, -encrypt]
    Packets: DM1 DH1 DM3 DH3 DM5 DH5 HV1 HV2 HV3
    Role: allow switch, remain slave
    Baseband:
        Manufacture: Cambridge Silicon Radio, id: 10
        Features: 1.1 compliant
    Buffers:
        ACL: 8 x 192 bytes
        SCO: 8 x 64 bytes
    Suported features:
        Packet types: 3-slots, 5-slots
        Radio features: RSSI, CQD data rate, paging scheme
        Policy: switch, hold mode, sniff mode, park mode
        Encryption: supported
        Clock modes: slot offset, timing accuracy
        Audio: SCO, HV2, HV3, u-Law log, a-Law log, CVSD, transparent SCO
        Power Control: supported
# cat /proc/tty/driver/serial
serinfo:1.0 driver:5.05c revision:Jun 28 2005
0: uart:PXA UART port:F8100000 irq:22 baud:460800 tx:5800 rx:12752 RTS|CTS|DTR|DSR|CD|RI
1: uart:PXA UART port:F8200000 irq:21 tx:0 rx:0
2: uart:PXA UART port:F8700000 irq:20 tx:0 rx:0
3: uart:16C950/954 port:F60003F8 irq:135 tx:0 rx:0
#
Another thing comes to mind is how to control the power of BT module? Of course, bt draws much less then wi-fi, but still you won't probably want to shorten your battery life more than absolutely necessary. I'm thinking of trying to use some controlled power domain for +3.3V if I can find any inside C1K. I.e. irda diode or maybe sd/mmc slot? Any ideas?
-albertr