Match stock Hyundai button logic

[sshane]

Currently we diverge from the original behavior when openpilot (alpha) longitudinal is used, which has confused some users in the past having them ask on Discord how to engage.

We should match the stock longitudinal button logic in panda and openpilot, here's what we don't match:

• [ ] CAN cars with set, resume, and main on button
  • [ ] Match main on button, which is a grate on whether cruise is "available". For example, pressing it has no effect on availability, nor resetting cruise speed, etc.
  • [ ] Resume should not be allowed if no cruise speed set (immediately after toggling main/availability)
• [ ] CAN and CAN FD cars with set, pause/resume, and main on button that toggles cruise:
  • [ ] Above criteria for main button, in addition to enabling cruise on rising edge the first time.
  • [ ] Pause/resume button should toggle cruise on and off if cruise is available.
• [ ] Not all HKG cars have this main and pause/resume button functionality and this button shows up as the normal resume button to openpilot, so we ideally need a way to differentiate these buttons/cars.

This needs to be done for both Hyundai's CAN and CAN FD platforms.

[BBBmau]

Looking to work on this to get a good understanding of how the engaging works.

This needs to be done for both Hyundai's CAN and CAN FD platforms.; if both CAN /CAN FD platforms are needed in hyundai, why are we wanting to match it to the hyundai button logic if that logic also needs to be replaced?

Been looking over it and it seems to make sense how disengaging and engaging works but that one part is what puzzles me.

[BBBmau]

found what I was looking for, after looking through car_controller.py in /hyundai I saw that the stock hyundai logic is just def create_button_messages(self, CC: car.CarControl, CS: car.CarState, use_clu11: bool): that's created in that same file.

I'll create a draft PR once I feel confident with one car and move on to others. I look forward to your comments on it! 👍🏼