Hello,
I started porting LPCOpen for LPC122x devices from the lpc_chip11cxx_lib library, I published it on GitHub.
Please note, that it is not yet tested, but the basic features of the MCU seem to work fine in my project.
Feel free to contribute.
GitHub - petipok/lpc_chip_122x: LPCOPEN chip library for NXP LPC 122x devices