Communicate with ardunio 2560 with android phone over cable (serial comm c++)

Projects Interfacing w/ Software on the Computer
1

Hi there, i'm trying to read/send commands to ardunio 2560, its more like android based question but i dont know where to ask, maybe someone had similar issues.
I connect phone to ardunio via otg cable, phone sees the device but i cannot find any valid file descriptor to use i have several /dev/tty devices but all of them report that read function would block, even when i set serial communication to be nonblocking, baud rates match, and i am supposed to receive a text from ardunio board (it controls a 3d printer)
After connecting phone to board it creates /dev/bus/001/'devnum' node but its not a tty device so i cannot set baudrate etc for this so i tried various tty fds on /dev/ node however they seem not to work at all
I tested if printer is being able to work with other 3rd party software(on phone) and it works i can send commands to printer (i think programs written in java - its called 3d fox) so i think i should be able to find a proper file descriptor and refer to it, so at least i would know that if im referencing to valid fd i have a bug in my application, however i cant use java and im very happy about it so its pure c/c++ app.
I also tried to find devpath in /sys/class node but it seems phone doesnt create any new dev/tty node and doesnt even show devpath at all

dmesg | grep usb returns only this garbage:

[499667.618103s][pid:29191,cpu0,kworker/0:2][USB_DEBUG]hw_is_usb_cable_connected ret is 0 !
[499667.813842s][pid:29191,cpu0,kworker/0:2][USB][hisi_usb_otg_event]event: 2
[499667.894012s][pid:28738,cpu1,kworker/u16:0][usbotg][dwc_otg_core_init]:usb mode Host
[499668.004119s][pid:28738,cpu1,kworker/u16:0][I/smpl] charge_usb_notifier_call 146 receive usb event:5, in_charging:0, valid_event:0
[499668.005676s][pid:28738,cpu1,kworker/u16:0][USB][handle_event]hisi usb_status: OFF -> HOST
[499683.722137s][pid:29191,cpu0,kworker/0:2]usb 1-1: new full-speed USB device number 14 using dwc_otg
[499683.933166s][pid:29191,cpu0,kworker/0:2]usb 1-1: New USB device found, idVendor=1a86, idProduct=7523
[499683.933197s][pid:29191,cpu0,kworker/0:2]usb 1-1: New USB device strings: Mfr=0, Product=2, SerialNumber=0
[499683.933227s][pid:29191,cpu0,kworker/0:2]usb 1-1: Product: USB2.0-Serial

Cheers

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According to https://hackernoon.com/10-creative-ways-to-use-otg-adapter-with-smartphones-27a86082cc6 you'll have to root your smartphone to make use of OTG.

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I already have root, this is why i provided data above (like dmesg output or if any dev node were created), ill need somehow to tell android that this device is an tty device and create proper node, detecting new plugged hardware is trivial, but then i have no idea how to create a proper filedescriptor that refers to arduino itself