finding bluetooth serial port

[Grant Edwards]

On 2007-11-07, Paul Sijben <paul.sijben at xs4all.nl> wrote:

> To automate/ease configuration in my app I am trying to find
> out to which serial port a certain bluetooth device is
> connected. With pybluez I can find out which bluetooth devices
> I have, but it will not tell me the serial port they are
> mapped to.
>
> Is there a way to figure this out from python? (I am
> insterested in the platforms WinXP and linux primarily)

Under linux, the "right" thing to do is to write a udev rule so
that the device has a predictiable name (or symlink).

http://reactivated.net/writing_udev_rules.html

If you don't want to write a udev rule, you'll need to bascally
re-implement udev by parsing the sysfs directory tree until you
find the device you're looking for. Here's how to do it for USB
(I assume BT works in a similar fashion).  

Let's say I know the device has vendor ID 0403, product ID
6001, and serial number 123456.

I search through the directories under /sys/devices until I
find a directory containing three files named

  idProduct
  idVendor
  serial  

Which contain the three strings I'm looking for.

In this case:

# cat /sys/devices/pci0000:00/0000:00:10.3/usb5/5-1/idVendor 
0403
# cat /sys/devices/pci0000:00/0000:00:10.3/usb5/5-1/idProduct
6001
# cat /sys/devices/pci0000:00/0000:00:10.3/usb5/5-1/serial   
12345678

Once you've found that directory, you can look at the other
entries to find out whatever you want to know about the device:

/sys/devices/pci0000:00/0000:00:10.3/usb5/5-1/
|-- 5-1:1.0
|   |-- bAlternateSetting
|   |-- bInterfaceClass
|   |-- bInterfaceNumber
|   |-- bInterfaceProtocol
|   |-- bInterfaceSubClass
|   |-- bNumEndpoints
|   |-- bus -> ../../../../../../bus/usb
|   |-- driver -> ../../../../../../bus/usb/drivers/ftdi_sio
|   |-- ep_02 -> ../../../../../../devices/pci0000:00/0000:00:10.3/usb5/5-1/5-1:1.0/usbdev5.42_ep02
|   |-- ep_81 -> ../../../../../../devices/pci0000:00/0000:00:10.3/usb5/5-1/5-1:1.0/usbdev5.42_ep81
|   |-- interface
|   |-- modalias
|   |-- power
|   |   |-- state
|   |   `-- wakeup
|   |-- subsystem -> ../../../../../../bus/usb
|   |-- ttyUSB0
|   |   |-- bus -> ../../../../../../../bus/usb-serial
|   |   |-- driver -> ../../../../../../../bus/usb-serial/drivers/ftdi_sio
|   |   |-- power
|   |   |   |-- state
|   |   |   `-- wakeup
|   |   |-- subsystem -> ../../../../../../../bus/usb-serial
|   |   |-- tty:ttyUSB0 -> ../../../../../../../class/tty/ttyUSB0
|   |   `-- uevent
|   |-- uevent
|   |-- usb_endpoint:usbdev5.42_ep02 -> ../../../../../../devices/pci0000:00/0000:00:10.3/usb5/5-1/5-1:1.0/usbdev5.42_ep02
|   |-- usb_endpoint:usbdev5.42_ep81 -> ../../../../../../devices/pci0000:00/0000:00:10.3/usb5/5-1/5-1:1.0/usbdev5.42_ep81
|   |-- usbdev5.42_ep02
|   |   |-- bEndpointAddress
|   |   |-- bInterval
|   |   |-- bLength
|   |   |-- bmAttributes
|   |   |-- dev
|   |   |-- device -> ../../../../../../../devices/pci0000:00/0000:00:10.3/usb5/5-1/5-1:1.0
|   |   |-- direction
|   |   |-- interval
|   |   |-- power
|   |   |   |-- state
|   |   |   `-- wakeup
|   |   |-- subsystem -> ../../../../../../../class/usb_endpoint
|   |   |-- type
|   |   |-- uevent
|   |   `-- wMaxPacketSize
|   `-- usbdev5.42_ep81
|       |-- bEndpointAddress
|       |-- bInterval
|       |-- bLength
|       |-- bmAttributes
|       |-- dev
|       |-- device -> ../../../../../../../devices/pci0000:00/0000:00:10.3/usb5/5-1/5-1:1.0
|       |-- direction
|       |-- interval
|       |-- power
|       |   |-- state
|       |   `-- wakeup
|       |-- subsystem -> ../../../../../../../class/usb_endpoint
|       |-- type
|       |-- uevent
|       `-- wMaxPacketSize
|-- bConfigurationValue
|-- bDeviceClass
|-- bDeviceProtocol
|-- bDeviceSubClass
|-- bMaxPacketSize0
|-- bMaxPower
|-- bNumConfigurations
|-- bNumInterfaces
|-- bcdDevice
|-- bmAttributes
|-- bus -> ../../../../../bus/usb
|-- configuration
|-- devnum
|-- driver -> ../../../../../bus/usb/drivers/usb
|-- ep_00 -> ../../../../../devices/pci0000:00/0000:00:10.3/usb5/5-1/usbdev5.42_ep00
|-- event_char
|-- idProduct
|-- idVendor
|-- manufacturer
|-- maxchild
|-- power
|   |-- state
|   `-- wakeup
|-- product
|-- serial
|-- speed
|-- subsystem -> ../../../../../bus/usb
|-- uevent
|-- usb_device:usbdev5.42 -> ../../../../../class/usb_device/usbdev5.42
|-- usb_endpoint:usbdev5.42_ep00 -> ../../../../../devices/pci0000:00/0000:00:10.3/usb5/5-1/usbdev5.42_ep00
|-- usbdev5.42_ep00
|   |-- bEndpointAddress
|   |-- bInterval
|   |-- bLength
|   |-- bmAttributes
|   |-- dev
|   |-- device -> ../../../../../../devices/pci0000:00/0000:00:10.3/usb5/5-1
|   |-- direction
|   |-- interval
|   |-- power
|   |   |-- state
|   |   `-- wakeup
|   |-- subsystem -> ../../../../../../class/usb_endpoint
|   |-- type
|   |-- uevent
|   `-- wMaxPacketSize
`-- version


If you want to search by something other than the product id,
vendor id and serial number, then pick some other of the files
above that will have identifiable contents and look for that.

-- 
Grant Edwards                   grante             Yow! We just joined the
                                  at               civil hair patrol!
                               visi.com