Tools:

• Android 4+ device (checked only on 5.0 and 4.4);
  
• USB OTG device support;
  
• root access;
  
• file manager with root support (in my case, this is Total Commander);
  
• text editor (in my case it is Total Commander again);
  
• a sheet of paper and a pencil;
  
• USB Device Info(to determine the properties of the device);
  
• Keytest(to display the device button codes)temporarily unavailable on the link, download from the forum link below.
  Another program that displays button codes and axis actionsGoogle play
  Universal program for testing buttons, editing actions and creating a configGamepad tester

Also, these applications can be downloaded on the forumNative support for input devices (Post # 36465278)

1. Creating a file with VID and PID
We connect our input device and launch the USB Device Info application. We are interested in the Linux tab, in which we select our device (I had it last in the list) and look for the values ​​of the Vendor ID and Product ID lines. In my case it was 0c45 and 7700, respectively.


Also VID and PID can be viewed by connecting the device to the PC.


For Bluetooth devices:
You can find these values ​​for Bluetooth devices by opening the file / proc / bus / input / devices.

Copy any file from / system / usr / keylayout to sdcard and rename it according to the received data; for my joystick, the name is:Vendor_0c45_Product_7700.kl. (Note that letter case does matter)

2. Getting Button Codes
Launch the KeyTest application and, armed with paper and a pencil, we start alternately pressing the buttons on the device, recording the numbers displayed after scanCode =. I wrote down the codes, placing them on paper, like buttons on a gamepad.

From the program you can exit only by the button "Home".

ATTENTION!
If Gamepad is visible in the first step, butKeytest does not respond on pressing, you may not have the required module in the kernel - say "thank you" to the author of the firmware.
But do not despair, there is a possible solution.Native support for input devices (Post wm-hater # 52134473)

3. Mapping buttons
Now that the codes for all keys have become known, it is necessary to prescribe their functions. There are two ways:
a) find a device among the configs available in Android that is as close as possible to yours, and simply change the button codes in it by copying the contents to your file;
b) prescribe everything yourself.
I went the second way, because my joystick has only a control cross and four buttons. First you need to understand the syntax of the file layout, it is very simple:

key button code action_key

But then the question arose: what actions of the buttons to write in the config? For many years of using various gamepads on Android, I have determined for myself that the most universal config is the Sony Xperia Play layout, it behaves equally well in games and in the system interface.

Ok Google key mapping for Xperia Play


We are interested in the third column, but the record of actions in it is slightly different from those that were found in the system - this is not an obstacle, just remove KEYCODE_.

I register my buttons (remember the sheet of pencil notes? It's time to find it ...):
!!! ATTENTION !!!
Need a text editor with support for unix encoding!
Notepad from Windows is NOT suitable,
Use, for example, Notepad ++

But here it was not without nuances. At Sony, the KEYCODE_BACK action (the “back” button, which is familiar to us, is assigned to the “circle” button). It is easy to guess that pressing such a button in the game can cause a nervous breakdown. And the thing is that during the game on Xplay, this button takes an alternative value - KEYCODE_BUTTON_B. Here we prescribe it.
The offset along the axis is written as:

4. The moment of truth
Save our file and copy it to the / system / usr / keylayout folder. Set rights -rw -r -r (644). We reboot the device (I didn’t do this myself, just blocked and unlocked, but for the purity of conscience and experiment I had to write it).

We connect our device, and if everything is done correctly, then you can immediately use the “crossbar” to navigate the Android menu. The button assigned to DPAD_CENTER will be the select button, and BUTTON_B the back button.

Q:I prescribe everything correctly, but the config does not cling.
BUT: If you register action codes with an error, for example:
key 123BUTTON_HOMEinstead of key 123HOME
then the system will consider this file erroneous.
The best way to check if your kl file is picked up by the system or not is to erase all keycodes or comment them out with a # sign:
#key 123 BUTTON_HOME
If the file is picked up - there will be no reaction to the buttons, but everything will be displayed in KeyTest.

Q:I prescribe everything correctly and without errors, but all or part of the buttons do not work.
BUT: Try writing scancode in hex format: Native support for input devices (Post romanctest # 69194647)
Q:Dualshok 4 constantly falls off or works with a delay.
BUT: Native support for input devices (Post maxmergov # 81264882)

About .kl:https://source.android.com/devices/input/key-layout-files
About .kcm:https://source.android.com/devices/input/key-character-map-files
About .idc:https://source.android.com/devices/input/input-device-configuration-files

https://youtu.be/9FszPvF-zoQ
Thank you saykipishOok

#
! QU RacePad

A
acme ga-05
Acme Pro GA-03

D
Defender Racer Wireless PRO
Dualshock 4
Dual Shock (Not original wired and wireless)
Dialog GP-A11
Dialog GP-A11RF (no wired version)
Defender Mobile Master
Defender Game Racer X7

E
EXEQ NEONLight
EXEQ Spitfire
EXEQ MechWarrior

G
GamepadPlus
Genius MaxFire Pandora Pro
Genius Maxfire G12 Wireles
Genius MaxFire G-12U Vibration
Gembird JPD-Dualforce2
Genius Maxfire Blaze 3

I
iPEGA 9023
ipega 9025
Ipega-9017
ipega 9028

L
Logitech rumblepad 2
Logitech Wireless Gamepad F710
Logitech f710 wireless
Logitech Gamepad F310 (USB)
Logitech Rumble Gamepad F510 (USB)
Logitech chillstream controller

M
MEEP! Joystick

N
Nyko playpad / playpad pro

O
Oklick GP-315M

S
SpeedLink TORID SL-6576-BK-01
Saitek P2500 Rumble Force PAD
Speedlink strike gamepad white
SVEN X-Pad
Startex doubleshock

T
Thrustmaster Dual Analog 4

W
WAMO G910 / Pro

X
Xiaomi gamepad
Xbox 360 wireless receiver
Xbox controllerler