PCNT clock may be deactivated after migration to 0.23

[DamienEspitallier]

Bug description

0.23 has changed the clock enable algorithm to use GenericPeripheralGuard. But it does not work when a PCNT is initialized in a function which return only a reference to a counter as it will drop the partially moved PCNT/Unit variables

To Reproduce

here is my function which trigger the bug

fn init_counters(
        pcnt: PCNT,
        left_pin_a: Input,
        left_pin_b: Input,
        right_pin_a: Input,
        right_pin_b: Input,
    ) -> (
        pcnt::unit::Counter<'static, 0>,
        pcnt::unit::Counter<'static, 1>,
    ) {
      let pcnt = Pcnt::new(pcnt);

      let u0 = pcnt.unit0;
      u0.set_filter(Some(min(10u16 * 80, 1023u16))).unwrap();
      u0.clear();

      let ch0 = &u0.channel0;
      ch0.set_ctrl_signal(left_pin_a.peripheral_input());
      ch0.set_edge_signal(left_pin_b.peripheral_input());
      ch0.set_ctrl_mode(
          pcnt::channel::CtrlMode::Reverse,
          pcnt::channel::CtrlMode::Keep,
      );
      ch0.set_input_mode(
          pcnt::channel::EdgeMode::Decrement,
          pcnt::channel::EdgeMode::Increment,
      );

      let ch1 = &u0.channel1;
      ch1.set_ctrl_signal(left_pin_b.peripheral_input());
      ch1.set_edge_signal(left_pin_a.peripheral_input());
      ch1.set_ctrl_mode(
          pcnt::channel::CtrlMode::Reverse,
          pcnt::channel::CtrlMode::Keep,
      );
      ch1.set_input_mode(
          pcnt::channel::EdgeMode::Increment,
          pcnt::channel::EdgeMode::Decrement,
      );

      let u1 = pcnt.unit1;
      u1.set_filter(Some(min(10u16 * 80, 1023u16))).unwrap();
      u1.clear();

      let ch0 = &u1.channel0;
      ch0.set_ctrl_signal(right_pin_a.peripheral_input());
      ch0.set_edge_signal(right_pin_b.peripheral_input());
      ch0.set_ctrl_mode(
          pcnt::channel::CtrlMode::Reverse,
          pcnt::channel::CtrlMode::Keep,
      );
      ch0.set_input_mode(
          pcnt::channel::EdgeMode::Decrement,
          pcnt::channel::EdgeMode::Increment,
      );

      let ch1 = &u1.channel1;
      ch1.set_ctrl_signal(right_pin_b.peripheral_input());
      ch1.set_edge_signal(right_pin_a.peripheral_input());
      ch1.set_ctrl_mode(
          pcnt::channel::CtrlMode::Reverse,
          pcnt::channel::CtrlMode::Keep,
      );
      ch1.set_input_mode(
          pcnt::channel::EdgeMode::Increment,
          pcnt::channel::EdgeMode::Decrement,
      );

      u0.listen();
      u0.resume();
      u1.listen();
      u1.resume();

      let counter_left = u0.counter.clone();
      let counter_right = u1.counter.clone();

      (counter_left, counter_right)
  }

At the end, pcnt and units will be dropped and counters will be broken as the clock is now deactivated.

For now, I "fixed" the issue in my code by using the following hack:

let pcnt = Pcnt::new(pcnt);
let pcnt = ManuallyDrop::new(pcnt);

Expected behavior

PCNT clock should be enabled as long as a reference to pcnt, unit or counter is valid.

Environment

• Target device: ESP32-S3
• Crate name and version: esp-hal 0.23.1

[Dominaezzz]

AHH, interesting use case. Each object basically needs a guard field in them