Make USB MIDI interface names customizable

[brushmate]

• Fixes usb_midi Device Name #4191

This pull request should solve the issues described in #4191 by introducing 4 new methods to the usb_midi module that allow for customizing the MIDI streaming interface, audio control interface, MIDI IN jack, and MIDI OUT jack names.

As suggested by @dhalbert I took a look at #8989 and basically just copied the code and adapted it to usb_midi. Since I have like zero experience in C programming I would be glad to get some feedback on the code. I feel like there are some unnecessary repetitions.

I tested this on a Raspberry Pi Pico.

[dhalbert]

Thanks for working on this!

Instead of four different routines, how about a single routine with optional arguments? Here is the signature:

usb_midi.set_names(self, *, streaming_interface_name = None, audio_control_interface_name = None, in_jack_name = None, out_jack_name = None)

They will be MP_ARG_KEY_ONLY and won't change if the arg is the default None. There are a lot of examples of this kind of thing in constructors, and also in .configure in busio.SPI.configure().

[brushmate]

I guess that makes sense. I was able to implement this method, but there is a lot of repeated code for each argument. What would be an idiomatic approach for getting rid of the repetitions?

[dhalbert]

I guess that makes sense. I was able to implement this method, but there is a lot of repeated code for each argument. What would be an idiomatic approach for getting rid of the repetitions?

You could just factor the repeated code into a static helper routine that takes two arguments, the input name and where to put it.

[brushmate]

I tried to do that, but failed. CircuitPython will always fall back to the default values. I guess something is wrong with all this pointer magic, but I have no clue how to properly debug the code.

[dhalbert]

I am recovering the ae9197b change before the refactoring I requested, and will try to fix this up on your fork branch.

[dhalbert]

I touched up the last commit so it works, touch up the documentation, and also fixed a build overflow problem.

test boot.py:

import usb_midi
usb_midi.set_names(streaming_interface_name="new_streaming_interface_name", audio_control_interface_name="new_audio_control_interface_name", in_jack_name="new_in_jack_name", out_jack_name="new_out_jack_name")

Testing the name setting:

$ sudo lsusb -vd 239a:80f2 | egrep 'iJack|iInterface'
      iInterface              4 CircuitPython CDC control
      iInterface              5 CircuitPython CDC data
      iInterface              6 CircuitPython Mass Storage
      iInterface              7 CircuitPython HID
      iInterface              9 new_audio_control_interface_name
      iInterface              8 new_streaming_interface_name
        iJack                  10 new_in_jack_name
        iJack                   0 
        iJack                  11 new_out_jack_name
        iJack                   0 

[dhalbert]

Thank you for this!

[brushmate]

Thank you for the assistance and the quick feedback on this PR!