udev: A passagem de parâmetros via $ attr {key} não funciona. Como resolver isso?

Question

Eu quero enumerar minhas pontes USB-UART com meu próprio script. O script deve ser chamado com alguns atributos e retornar um novo nome de nó do devfs.

1. Eu testei o script no console:

   ./rc3e.py -d get-devfs-node tty --vendor 10C4 --product EA60 --driver cp210x --serial "Board=KC705;Serial=5081a76781f40229d39e6c9802400fd2"
   KC705_0/ttyUSB
   

2. Eu implementei uma regra do udev estática:

   # Silicon Labs - CP2103 USB to UART Bridge Controller
   SUBSYSTEM=="tty", SUBSYSTEMS=="usb", ATTRS{idProduct}=="ea60", ATTRS{idVendor}=="10c4", ATTRS{serial}=="Board=KC705;Serial=5081a76781f40229d39e6c9802400fd2", SYMLINK+="KC705_0/ttyUSB"
   

3. Estou testando a regra do udev com /usr/bin/logger :

   SUBSYSTEM=="tty", SUBSYSTEMS=="usb", PROGRAM="/usr/bin/logger -p user.error 'product=%attr{idProduct} vendor=$attr{idVendor} drivers=$driver serial=$attr{serial}'"
   

   Aqui estou preso.
   A linha reportada em /var/log/syslog é esta:

   Sep 23 15:12:26 xxxxxx root: product= vendor= drivers=cp210x serial=
   

$driver é substituído, mas $att{key} está sempre vazio.

Esta é minha udevadm info -a -n /dev/ttyUSB2 output:

udevadm info -a -n /dev/ttyUSB2

Udevadm info starts with the device specified by the devpath and then
walks up the chain of parent devices. It prints for every device
found, all possible attributes in the udev rules key format.
A rule to match, can be composed by the attributes of the device
and the attributes from one single parent device.

  looking at device '/devices/pci0000:00/0000:00:14.0/usb1/1-3/1-3:1.0/ttyUSB2/tty/ttyUSB2':
    KERNEL=="ttyUSB2"
    SUBSYSTEM=="tty"
    DRIVER==""

  looking at parent device '/devices/pci0000:00/0000:00:14.0/usb1/1-3/1-3:1.0/ttyUSB2':
    KERNELS=="ttyUSB2"
    SUBSYSTEMS=="usb-serial"
    DRIVERS=="cp210x"                                      <-- key of interrest
    ATTRS{port_number}=="0"

  looking at parent device '/devices/pci0000:00/0000:00:14.0/usb1/1-3/1-3:1.0':
    KERNELS=="1-3:1.0"
    SUBSYSTEMS=="usb"
    DRIVERS=="cp210x"
    ATTRS{bAlternateSetting}==" 0"
    ATTRS{bInterfaceClass}=="ff"
    ATTRS{bInterfaceNumber}=="00"
    ATTRS{bInterfaceProtocol}=="00"
    ATTRS{bInterfaceSubClass}=="00"
    ATTRS{bNumEndpoints}=="02"
    ATTRS{interface}=="CP2103 USB to UART Bridge Controller"
    ATTRS{supports_autosuspend}=="1"

  looking at parent device '/devices/pci0000:00/0000:00:14.0/usb1/1-3':
    KERNELS=="1-3"
    SUBSYSTEMS=="usb"
    DRIVERS=="usb"
    ATTRS{authorized}=="1"
    ATTRS{avoid_reset_quirk}=="0"
    ATTRS{bConfigurationValue}=="1"
    ATTRS{bDeviceClass}=="00"
    ATTRS{bDeviceProtocol}=="00"
    ATTRS{bDeviceSubClass}=="00"
    ATTRS{bMaxPacketSize0}=="64"
    ATTRS{bMaxPower}=="100mA"
    ATTRS{bNumConfigurations}=="1"
    ATTRS{bNumInterfaces}==" 1"
    ATTRS{bcdDevice}=="0100"
    ATTRS{bmAttributes}=="80"
    ATTRS{busnum}=="1"
    ATTRS{configuration}==""
    ATTRS{devnum}=="2"
    ATTRS{devpath}=="3"
    ATTRS{idProduct}=="ea60"                               <-- key of interrest
    ATTRS{idVendor}=="10c4"                                <-- key of interrest
    ATTRS{ltm_capable}=="no"
    ATTRS{manufacturer}=="Silicon Labs"
    ATTRS{maxchild}=="0"
    ATTRS{product}=="CP2103 USB to UART Bridge Controller"
    ATTRS{quirks}=="0x0"
    ATTRS{removable}=="unknown"
    ATTRS{serial}=="Board=KC705;Serial=5081a76781f40229d39e6c9802400fd2"    <-- key of interrest
    ATTRS{speed}=="12"
    ATTRS{urbnum}=="258427"
    ATTRS{version}==" 1.10"

O que devo alterar para passar esses parâmetros ao meu script?

EDIT 1:

root@fpga-cloud:/dev# udevadm info /dev/ttyUSB2
P: /devices/pci0000:00/0000:00:14.0/usb1/1-3/1-3:1.0/ttyUSB2/tty/ttyUSB2
N: ttyUSB2
S: KC705_0/ttyUSB
S: serial/by-id/usb-Silicon_Labs_CP2103_USB_to_UART_Bridge_Controller_Board=KC705_Serial=5081a76781f40229d39e6c9802400fd2-if00-port0
S: serial/by-path/pci-0000:00:14.0-usb-0:3:1.0-port0
S: ttyUSB.KC705
E: DEVLINKS=/dev/KC705_2/ttyUSB /dev/serial/by-id/usb-Silicon_Labs_CP2103_USB_to_UART_Bridge_Controller_Board=KC705_Serial=5081a76781f40229d39e6c9802400fd2-if00-port0 /dev/KC705_1/ttyUSB /dev/ttyUSB.KC705 /dev/serial/by-path/pci-0000:00:14.0-usb-0:3:1.0-port0
E: DEVNAME=/dev/ttyUSB2
E: DEVPATH=/devices/pci0000:00/0000:00:14.0/usb1/1-3/1-3:1.0/ttyUSB2/tty/ttyUSB2
E: ID_BUS=usb
E: ID_MM_CANDIDATE=1
E: ID_MODEL=CP2103_USB_to_UART_Bridge_Controller
E: ID_MODEL_ENC=CP2103\x20USB\x20to\x20UART\x20Bridge\x20Controller
E: ID_MODEL_FROM_DATABASE=CP210x UART Bridge / myAVR mySmartUSB light
E: ID_MODEL_ID=ea60
E: ID_PATH=pci-0000:00:14.0-usb-0:3:1.0
E: ID_PATH_TAG=pci-0000_00_14_0-usb-0_3_1_0
E: ID_PCI_CLASS_FROM_DATABASE=Serial bus controller
E: ID_PCI_INTERFACE_FROM_DATABASE=XHCI
E: ID_PCI_SUBCLASS_FROM_DATABASE=USB controller
E: ID_REVISION=0100
E: ID_SERIAL=Silicon_Labs_CP2103_USB_to_UART_Bridge_Controller_Board=KC705_Serial=5081a76781f40229d39e6c9802400fd2
E: ID_SERIAL_SHORT=Board=KC705_Serial=5081a76781f40229d39e6c9802400fd2
E: ID_TYPE=generic
E: ID_USB_DRIVER=cp210x
E: ID_USB_INTERFACES=:ff0000:
E: ID_USB_INTERFACE_NUM=00
E: ID_VENDOR=Silicon_Labs
E: ID_VENDOR_ENC=Silicon\x20Labs
E: ID_VENDOR_FROM_DATABASE=Cygnal Integrated Products, Inc.
E: ID_VENDOR_ID=10c4
E: MAJOR=188
E: MINOR=2
E: SUBSYSTEM=tty
E: TAGS=:systemd:
E: USEC_INITIALIZED=7849322