andypugh@DN2800:~$ cat /proc/bus/input/devices
...
I: Bus=0000 Vendor=0000 Product=0000 Version=0000
N: Name="matrix_kb.0"
P: Phys=
S: Sysfs=/devices/virtual/input/input13
U: Uniq=
H: Handlers=kbd event7
B: EV=3
B: KEY=3 ffffffff ffffffff ffffffff ffffffff ffffffff ffffffff ffffffff

andypugh@DN2800:~$ halcmd show pin
...
     7  bit   OUT         FALSE  matrix_kb.0.key.0.0
     7  bit   OUT         FALSE  matrix_kb.0.key.0.1
     7  bit   OUT         FALSE  matrix_kb.0.key.0.2
     7  bit   OUT         FALSE  matrix_kb.0.key.0.3
 ...