Move i2c to mod, split device and controller
Remove mode generic:
I don't think it's reasonable to use the i2c in device mode while
blocking, so I'm cutting the generic.
we'll need access to the pin io bank registers for an upcoming fix, and
having both `io` and `io_bank` or similar can get confusing quickly.
rename `io` to `gpio` to avoid this, and also match the type while there.
Change embassy-rp i2c.rs impl of embedded_hal_async::i2c::I2c::transaction
to only do the call to setup() for address once per call to transactions.
Calling setup multiple times results in I2C transactions being skipped
on the bus, even across calls to transaction() or devices.
- Move typelevel interrupts to a special-purpose mod: `embassy_xx::interrupt::typelevel`.
- Reexport the PAC interrupt enum in `embassy_xx::interrupt`.
This has a few advantages:
- The `embassy_xx::interrupt` module is now more "standard".
- It works with `cortex-m` functions for manipulating interrupts, for example.
- It works with RTIC.
- the interrupt enum allows holding value that can be "any interrupt at runtime", this can't be done with typelevel irqs.
- When "const-generics on enums" is stable, we can remove the typelevel interrupts without disruptive changes to `embassy_xx::interrupt`.
Assert "tx_empty" interrupt a little early so there's time to wake up
and start refilling the fifo before it drains. This avoids stalling the
i2c bus if the tx fifo completely drains.
This is an interrupt-driven async i2c master implementation. It makes as
best use of the RP2040's i2c block's fifos as possible to minimize
interrupts.
It implements embedded_hal_async::i2c for easy interop.
WIP async impl
