platform_frameworks_base/cmds/uinput/README.md

Usage

Two options to use the uinput command:

1. Interactive through stdin:

type uinput - into the terminal, then type/paste commands to send to the binary. Use Ctrl+D to signal end of stream to the binary (EOF).

This mode can be also used from an app to send uinput events. For an example, see the cts test case at: InputTestCase.java

When using another program to control uinput in interactive mode, registering a new input device (for example, a bluetooth joystick) should be the first step. After the device is added, you need to wait for the onInputDeviceAdded (see InputDeviceListener) notification before issuing commands to the device. Failure to do so will cause missed events and inconsistent behavior.

2. Using a file as an input:

type uinput <filename>, and the file will be used an an input to the binary. You must add a sufficient delay after a "register" command to ensure device is ready. The interactive mode is the recommended method of communicating with the uinput binary.

All of the input commands should be in pseudo-JSON format as documented below. See examples here.

The file can have multiple commands one after the other (which is not strictly legal JSON format, as this would imply multiple root elements).

Command description

1. register Register a new uinput device

Field	Type	Description
id	integer	Device id
command	string	Must be set to "register"
name	string	Device name
vid	16-bit integer	Vendor id
pid	16-bit integer	Product id
bus	string	Bus that device should use
configuration	int array	uinput device configuration
ff_effects_max	integer	ff_effects_max value
abs_info	array	ABS axes information

Device ID is used for matching the subsequent commands to a specific device to avoid ambiguity when multiple devices are registered.

Device bus is used to determine how the uinput device is connected to the host. The options are "usb" and "bluetooth".

Device configuration is used to configure uinput device. "type" field provides the UI_SET_* control code, and data is a vector of control values to be sent to uinput device, depends on the control code.

Field	Type	Description
type	integer	UI_SET_ control type
data	int array	control values

Device ff_effects_max must be provided if FFBIT is set.

Device abs_info fields are provided to set the device axes information. It is an array of below objects:

Field	Type	Description
code	integer	Axis code
info	object	ABS information object

ABS information object is defined as below:

Field	Type	Description
value	integer	Latest reported value
minimum	integer	Minimum value for the axis
maximum	integer	Maximum value for the axis
fuzz	integer	fuzz value for noise filter
flat	integer	values to be discarded
resolution	integer	resolution of axis

See struct input_absinfo) definitions.

Example:

{
  "id": 1,
  "command": "register",
  "name": "Keyboard (Test)",
  "vid": 0x18d2,
  "pid": 0x2c42,
  "bus": "usb",
  "configuration":[
        {"type":100, "data":[1, 21]},  // UI_SET_EVBIT : EV_KEY and EV_FF
        {"type":101, "data":[11, 2, 3, 4]},   // UI_SET_KEYBIT : KEY_0 KEY_1 KEY_2 KEY_3
        {"type":107, "data":[80]}    //  UI_SET_FFBIT : FF_RUMBLE
  ],
  "ff_effects_max" : 1,
  "abs_info": [
        {"code":1, "info": {"value":20, "minimum":-255,
                            "maximum":255, "fuzz":0, "flat":0, "resolution":1}
        },
        {"code":8, "info": {"value":-50, "minimum":-255,
                            "maximum":255, "fuzz":0, "flat":0, "resolution":1}
        }
  ]
}

2. delay Add a delay to command processing

Field	Type	Description
id	integer	Device id
command	string	Must be set to "delay"
duration	integer	Delay in milliseconds

Example:

{
  "id": 1,
  "command": "delay",
  "duration": 10
}

3. inject Send an array of uinput event packets [type, code, value] to the uinput device

Field	Type	Description
id	integer	Device id
command	string	Must be set to "inject"
events	integer array	events to inject

The "events" parameter is an array of integers, encapsulates evdev input_event type, code and value, see the example below.

Example:

{
  "id": 1,
  "command": "inject",
  "events": [0x01, 0xb,  0x1,   // EV_KEY, KEY_0, DOWN
             0x00, 0x00, 0x00,  // EV_SYN, SYN_REPORT, 0
             0x01, 0x0b, 0x00,  // EV_KEY, KEY_0, UP
             0x00, 0x00, 0x00,  // EV_SYN, SYN_REPORT, 0
             0x01, 0x2,  0x1,   // EV_KEY, KEY_1, DOWN
             0x00, 0x00, 0x01,  // EV_SYN, SYN_REPORT, 0
             0x01, 0x02, 0x00,  // EV_KEY, KEY_1, UP
             0x00, 0x00, 0x01   // EV_SYN, SYN_REPORT, 0
            ]
}

Notes

1. As soon as EOF is reached (either in interactive mode, or in file mode), the device that was created will be unregistered. There is no explicit command for unregistering a device.
2. The getevent utility can used to print out the key events for debugging purposes.