#cat /proc/bus/input/devices
(snipped the other devices)
I: Bus=0011 Vendor=0002 Product=0001 Version=0000
N: Name="PS/2 Generic Mouse"
P: Phys=isa0060/serio3/input0
S: Sysfs=/devices/platform/i8042/serio3/input/input7
U: Uniq=
H: Handlers=mouse0 event7
B: PROP=0
B: EV=7
B: KEY=70000 0 0 0 0
B: REL=3

# evtest
(selected event 7)
/dev/input/event7:	PS/2 Generic Mouse
Input driver version is 1.0.1
Input device ID: bus 0x11 vendor 0x2 product 0x1 version 0x0
Input device name: "PS/2 Generic Mouse"
Supported events:
  Event type 0 (EV_SYN)
  Event type 1 (EV_KEY)
    Event code 272 (BTN_LEFT)
    Event code 273 (BTN_RIGHT)
    Event code 274 (BTN_MIDDLE)
  Event type 2 (EV_REL)
    Event code 0 (REL_X)
    Event code 1 (REL_Y)

From Xorg.0.log:
[    28.839] (II) config/udev: Adding input device PS/2 Generic Mouse (/dev/input/event7)
[    28.839] (**) PS/2 Generic Mouse: Applying InputClass "evdev pointer catchall"
[    28.839] (II) Using input driver 'evdev' for 'PS/2 Generic Mouse'
[    28.839] (II) Loading /usr/lib/xorg/modules/input/evdev_drv.so
[    28.839] (**) PS/2 Generic Mouse: always reports core events
[    28.839] (**) evdev: PS/2 Generic Mouse: Device: "/dev/input/event7"
[    28.839] (--) evdev: PS/2 Generic Mouse: Vendor 0x2 Product 0x1
[    28.839] (--) evdev: PS/2 Generic Mouse: Found 3 mouse buttons
[    28.839] (--) evdev: PS/2 Generic Mouse: Found relative axes
[    28.839] (--) evdev: PS/2 Generic Mouse: Found x and y relative axes
[    28.839] (II) evdev: PS/2 Generic Mouse: Configuring as mouse
[    28.839] (**) evdev: PS/2 Generic Mouse: YAxisMapping: buttons 4 and 5
[    28.839] (**) evdev: PS/2 Generic Mouse: EmulateWheelButton: 4, EmulateWheelInertia: 10, EmulateWheelTimeout: 200
[    28.839] (**) Option "config_info" "udev:/sys/devices/platform/i8042/serio3/input/input7/event7"
[    28.839] (II) XINPUT: Adding extended input device "PS/2 Generic Mouse" (type: MOUSE, id 12)
[    28.839] (II) evdev: PS/2 Generic Mouse: initialized for relative axes.
[    28.840] (**) PS/2 Generic Mouse: (accel) keeping acceleration scheme 1
[    28.840] (**) PS/2 Generic Mouse: (accel) acceleration profile 0
[    28.840] (**) PS/2 Generic Mouse: (accel) acceleration factor: 2.000
[    28.840] (**) PS/2 Generic Mouse: (accel) acceleration threshold: 4
[    28.840] (II) config/udev: Adding input device PS/2 Generic Mouse (/dev/input/mouse0)
[    28.840] (II) No input driver specified, ignoring this device.
[    28.840] (II) This device may have been added with another device file.