richard_damon wrote on Monday, September 12, 2016:
For a UART, it should be THAT hard, as it is inherently a straming device, so a POSIX stream isn’t that bad of a match. The challange with open, is that you aren’t just writting an open for the serial port, but there is just a single open function that needs to handle EVERY device you want to connect to, and this goes and impacts the entire I/O file lib. You can look at an open source implementation like newlib for an example of how to do this. That implementation was designed to be somewhat extensible with hooks to let you add devices to the library.
I2C might be a bit tougher if you are actually expecting to use read/write to talk to the device, as I2C isn’t a simple streaming protocal, but is block based with device specific headers for each block. On the Raspberry Pi, I2C is hooked in via ioctl for all transactions, but since all the calls are now very much device specific, since you don’t have a ‘big’ OS getting in your way, it would be much better to just use a native I2C driver that you directly call, and not add a ioctl translation layer in the middle.