lsudt

lsudt (list USB device tree) is a utility for listing USB devices as a tree including associated dev nodes and other information from udev.

This makes it much easier to understand the topology of a USB tree and the relationship between device nodes and the USB devices they originate from.

The utility provides filtering capabilities allowing you to filter by device path, port path, udev tag and udev ID_PATH.

Example Usage

# Filter by USB port path
$ lsudt -p 1-10
Port 1-10: Hub (2109:2813 / 1-10)
    Port 1: Hub (1a40:101 / 1-10.1)
        Port 1: Device (67b:2303 / 1-10.1.1)
           /dev/ttyUSB0

        Port 4: Device (bda:8152 / 1-10.1.4)
           Net: enx00e04c360033

    Port 4: Device (5e3:749 / 1-10.4)
       /dev/sda
       /dev/sda1
       /dev/sda2
       /dev/sda3
       /dev/sda4
       /dev/sda5
       /dev/sda6
       /dev/sda7
       /dev/sda8
       /dev/bsg/6:0:0:0
       /dev/sg0

# Filter by device path
$ lsudt -d /sys/devices/pci0000:00/0000:00:14.0/usb1/1-4 
Port 1-4: Device (46d:843 / 1-4)
   /dev/input/event5
   /dev/media0
   /dev/video0
   /dev/video1
   /dev/snd/pcmC1D0c
   /dev/snd/controlC1

# Filter by ID_PATH
$ lsudt -i pci-0000:00:14.0-usb-0:5
Port 1-5: Device (b0e:348 / 1-5)
   /dev/snd/pcmC3D0c
   /dev/snd/pcmC3D0p
   /dev/snd/controlC3
   /dev/hidraw2
   /dev/input/event22
   /dev/usb/hiddev1
 
# Filter by udev TAG
$ lsudt -t power-switch
Port 1-4: (1-4)
   /dev/input/event5

Port 1-5: (1-5)
   /dev/input/event22

Port 1-7: (1-7)
   /dev/input/event3

Port 1-9: (1-9)
   /dev/input/event7
   /dev/input/event9
   /dev/input/event8

# Show more information
$ lsudt -p 1-10.1 -u -s -e -l
Port 1: Hub (1a40:101 / 1-10.1)
   /dev/bus/usb/001/085 (pci-0000:00:14.0-usb-0:10.1)
    Port 1: Device (67b:2303 / 1-10.1.1)
       /dev/bus/usb/001/109 (pci-0000:00:14.0-usb-0:10.1.1)
       /dev/ttyUSB0 (pci-0000:00:14.0-usb-0:10.1.1:1.0)
       : /dev/serial/by-id/usb-Prolific_Technology_Inc._USB-Serial_Controller-if00-port0
       : /dev/serial/by-path/pci-0000:00:14.0-usb-0:10.1.1:1.0-port0

    Port 4: Device (bda:8152 / 1-10.1.4)
       /dev/bus/usb/001/086 (pci-0000:00:14.0-usb-0:10.1.4)
       Net: enx00e04c360033 (pci-0000:00:14.0-usb-0:10.1.4:1.0)

# Show help
$ lsudt -h
usage: lsudt [-h] [--version] [--show-devusb] [--show-idpath] [--show-empty-hubs]
             [--show-device-links] [--device-path DEVICE_PATH] [--port-path PORT_PATH]
             [--udev-tag TAG] [--udev-idpath ID_PATH]

View connected USB devices and device nodes

optional arguments:
  -h, --help            show this help message and exit
  --version             show program's version number and exit
  --show-devusb, -u     show /dev/usb/ device nodes
  --show-idpath, -s     show udev ID_PATH next to devices
  --show-empty-hubs, -e
                        show empty hubs
  --show-device-links, -l
                        show device links
  --device-path DEVICE_PATH, -d DEVICE_PATH
                        limit output to devices contained within a path starting with /sys/devices/
  --port-path PORT_PATH, -p PORT_PATH
                        limit output to devices downstream of a particular port path
  --label LABEL, -b LABEL
                        limit output to devices downstream of a particular label
  --udev-tag TAG, -t TAG
                        limit output to devices with udev tag
  --udev-idpath ID_PATH, -i ID_PATH
                        limit output to devices with a parent starting with given idpath

Installation

The easiest way to install lsudt is to use pip, as follows:

$ pip3 install lsudt

Alternatively you can clone the Github repo and install it as follows:

$ git clone https://github.com/The-Good-Penguin/lsudt.git
$ cd lsudt
$ pip3 install .

Labels

The USB tree can be better visualised by using labels. A user may create a configuration file that assigns text labels to specific devices.

For example consider the following USB tree:

$ lsudt -p 1-10
Port 1-10: Hub (2109:2813 / 1-10)
    Port 2: Hub (45b:209 / 1-10.2)
        Port 3: Device (67b:2303 / 1-10.2.3)
           /dev/ttyUSB0

        Port 4: Hub (1a40:101 / 1-10.2.4)
            Port 3: Device (67b:2303 / 1-10.2.4.3)
               /dev/ttyUSB1

            Port 4: Device (bda:8152 / 1-10.2.4.4)
               Net: enx00e04c360033

The same tree can be better visualised when using labels:

$ ./lsudt.py -p 1-10
Port 1-10: Hub (2109:2813 / 1-10)
    Port 2: Hub used for Raspberry Pi (45b:209 / 1-10.2)
        Port 3: Raspberry Pi UART (67b:2303 / 1-10.2.3)
           /dev/ttyUSB0

        Port 4: Additional hub (1a40:101 / 1-10.2.4)
            Port 3: USB relay (Pi power control) (67b:2303 / 1-10.2.4.3)
               /dev/ttyUSB1

            Port 4: Hub built in Ethernet (connected to Pi) (bda:8152 / 1-10.2.4.4)
               Net: enx00e04c360033

The configuration file for these labels is shown below:

segments:
  -
    identifier: raspberry_pi
    label: Hub used for Raspberry Pi
    ports:
      - port: 1
        label: UART
        env: UART
      - port: 3
        label: Raspberry Pi UART
        env: UART
      - port: 4
        label: Additional hub
      - port: 4.3
        label: USB relay (Pi power control)
        env: POWER
      - port: 4.4
        label: Hub built in Ethernet (connected to Pi)

mappings:
  -
    identifier: raspberry_pi
    #port: 1-10.2
    idpath: pci-0000:00:14.0-usb-0:5

Envs

envs are the method by which a labelled port can have a generated environment variable that bears the path to its node i.e. /dev/sda1

Using the above raspberry pi example

      - port: 3
        label: Raspberry Pi UART
        env: UART

This will generate a string in the form of RASPBERRY_PI_UART_0=/dev/foo. This is based on the top level identifier (raspberry_pi) which is capitalised and, if necessary, converts '-' and ' ' to '_'. The env label given in env. The final number is the to differentiate several devices on the same hub e.g. /dev/sda /dev/sda1 /dev/sda2 will produce *_DISK_0, *_DISK_1, *_DISK_2 respectively.

This name/value string can then be parsed however the user sees fit. For example:

$ eval `lsudt -x -b raspberry_pi`
$ minicom -D ${RASPBERRY_PI_UART_0}

Options may also be applied to the env part of a yml. For example:

   env: DISK,sd

This Will ensure that only devices beginning with 'sd' are picked up. so /dev/sg1 will be dropped but /dev/sda1 will be kept.

Further to this it is guaranteed that all block devices will always be in alphabetical order in relation to their env enumeration. So in the case of:

$ ls /dev/sda*
   /dev/sda
   /dev/sda1
   /dev/sda2
   /dev/sdb

the provided strings will always be in order:

$ lsudt -x -b my_device
   MY_DEVICE_DISK_0=/dev/sda
   MY_DEVICE_DISK_1=/dev/sda1
   MY_DEVICE_DISK_2=/dev/sda2
   MY_DEVICE_DISK_3=/dev/sdb

Segments

A segment represents a fixed portion of the USB topology and consists of an identifier, label and set of labels and/or envs for child ports.

The segment is accompanied with a mapping that describes where the segment lives in the overall USB tree. In this way, the port path of the ports in a segment are relative to the port path in the mapping. In addition to a port mapping, segements can be associated with part of a tree via an idpath as shown in the above example.

This is useful as the segment can represent a fixed set of devices (e.g. a board in a board farm) and the mapping describes where it is (e.g. making it easier to move a board in a board farm).

The configuration can be split across any number of files. lsudt will scan for any files ending with the .yml suffix in the ~/.lsudt/ directory.

Finally a segment identifier can be used to filter the output of lsudt, e.g.

$ ./lsudt.py -b raspberry_pi
Port 2: Hub used for Raspberry Pi (45b:209 / 1-10.2)
    Port 3: Raspberry Pi UART (67b:2303 / 1-10.2.3)
       /dev/ttyUSB0

    Port 4: Additional hub (1a40:101 / 1-10.2.4)
        Port 3: USB relay (Pi power control) (67b:2303 / 1-10.2.4.3)
           /dev/ttyUSB1

        Port 4: Hub built in Ethernet (connected to Pi) (bda:8152 / 1-10.2.4.4)
           Net: enx00e04c360033

Waiting For Devices

If you have a device that might take a moment or two to come up (block devices for example) the script can be told to hold off outputting all of the name=value pairs until the requested name is present. This can be done using the --wait-for-env/-w flag. This flag accepts a list of values e.g. -w FIRST_NAME SECOND_NAME etc

Using our raspberry-pi example above if we wanted to wait for its UART to come up we would type:

$ lsudt -x -i pci-0000:00:14.0-usb-0:5 -w RASPBERRY_PI_UART_0

And this would stop the anything from being printed to stdout before RASPBERRY_PI_UART_0 is generated. We can also ask for multiple envs to be present and it will wait until all are present before printing:

$ lsudt -x -i pci-0000:00:14.0-usb-0:5 -w RASPBERRY_PI_UART_0 RASPBERRY_PI_POWER_0

By default the script will try 10 times (once a second). If you wish to CHANGE this then:

$ lsudt -x -i pci-0000:00:14.0-usb-0:5 -w RASPBERRY_PI_UART_0 -o -1 # Never stop trying
$ lsudt -x -i pci-0000:00:14.0-usb-0:5 -w RASPBERRY_PI_UART_0 -o 99 # try 99 times/for 99 seconds

Contributing

We welcome any feedback, bug reports, feature requests and pull requests. There is no mailing list associated with this project - please contribute via the GitHub Issues / Pull requests functionality.

Please run pylint and black on any code contributions.