phablet@ubuntu-phablet:~$ sudo udevadm test-builtin input_id /devices/platform/mtk-kpd/input/input0
calling: test-builtin
=== trie on-disk ===
tool version:          219
file size:         6711498 bytes
header size             80 bytes
strings            1721914 bytes
nodes              4989504 bytes
Load module index
Network interface NamePolicy= disabled on kernel command line, ignoring.
timestamp of '/etc/systemd/network' changed
timestamp of '/lib/systemd/network' changed
Parsed configuration file /lib/systemd/network/99-default.link
Created link configuration context.
ID_INPUT=1
capabilities/ev raw kernel attribute: 3
capabilities/ev decoded bit map:
  bit    0: 00000003
capabilities/abs raw kernel attribute: 0
capabilities/abs decoded bit map:
capabilities/rel raw kernel attribute: 0
capabilities/rel decoded bit map:
capabilities/key raw kernel attribute: 80 180000 0 40000800 1c0840 0 0 0
capabilities/key decoded bit map:
  bit    0: 00000000
  bit   32: 00000000
  bit   64: 00000000
  bit   96: 001C0840
  bit  128: 40000800
  bit  160: 00000000
  bit  192: 00180000
  bit  224: 00000080
properties raw kernel attribute: 0
properties decoded bit map:
test_key: checking bit block 0 for any keys; found=0
test_key: checking bit block 32 for any keys; found=0
test_key: checking bit block 64 for any keys; found=0
test_key: checking bit block 96 for any keys; found=1
test_key: checking bit block 128 for any keys; found=1
test_key: checking bit block 160 for any keys; found=1
test_key: checking bit block 192 for any keys; found=1
test_key: checking bit block 224 for any keys; found=1
ID_INPUT_KEY=1
Unload module index
Unloaded link configuration context.