usb

Probes all usb devices listed in the sysfs /sys/bus/usb/devices/.

Function Arguments

Name	Type	Description
dir_path	str, None	(optional; default: None) The path used to search for device sysfs data. First all symlinks are resolved, to the the “real” path. Then iteratively search toward parent folder until the remaining path contains the relevent data fields.

Description

This function goes through /sys/bus/usb/devices/ to read attributes of each usb device (also includes usb root hub) listed there. Each result should contain these fields:

• device_path: Pathname of the sysfs directory.

• idVendor

• idProduct

The result might also contain these optional fields if they are exported in the sysfs entry:

• manufacturer

• product

• bcdDevice

Examples

Let’s say the Chromebook has two usb devices. One of which (at /sys/bus/usb/devices/1-1) has the attributes:

• idVendor=0x0123

• idProduct=0x4567

• manufacturer=Google

• product=Google Fancy Camera

• bcdDevice=0x8901

And the other one (at /sys/bus/usb/devices/1-2) has the attributes:

• idVendor=0x0246

• idProduct=0x1357

• product=Goofy Bluetooth

Then the probe statement:

{
  "eval": "usb"
}

will have the corresponding probed result:

[
  {
    "bus_type": "usb",
    "idVendor": "0123",
    "idProduct": "4567",
    "manufacturer": "Google",
    "product": "Google Fancy Camera",
    "bcdDevice": "8901"
  },
  {
    "bus_type": "usb",
    "idVendor": "0246",
    "idProduct": "1357",
    "product": "Goofy Bluetooth"
  }
]

To verify if the Chromebook has Google Fancy Camera or not, you can write a probe statement like:

{
  "eval": "usb",
  "expect": {
    "idVendor": "0123",
    "idProduct": "4567"
  }
}

and verify if the camera field of the probed result dict contains elements or not.

You can also specify dir_path argument directly to ask the function to probe that sysfs USB entry. For example, the probe statement

{
  "eval": "usb:/sys/bus/usb/devices/1-1"
}

will have the corresponding probed results:

[
  {
    "bus_type": "usb",
    "idVendor": "0123",
    ...
  }
]