Add parameter for enabling pull-up and pull-down in RP PWM input mode

[pawel00100]

I created this simple change that allows pin B (the one that can be used as PWM counter input) to be set with pull-up or pull-down internal resistor.

I made tests for two most important cases. I was thinking about adding extra test for checking if the input is floating by default, but it even in case of code being wrong test could on occasion pass so I decided not to add it:

    // PWM input is floating by default
    {
        let pin2 = Input::new(&mut p11, Pull::Down);
        let pwm = Pwm::new_input(&mut p.PWM_CH3, &mut p7, Pull::None, InputMode::FallingEdge, cfg.clone());
        Timer::after_millis(1).await;
        assert!(pin2.is_low());
    }
    {
        let pin2 = Input::new(&mut p11, Pull::Up);
        let pwm = Pwm::new_input(&mut p.PWM_CH3, &mut p7, Pull::None, InputMode::FallingEdge, cfg.clone());
        Timer::after_millis(1).await;
        assert!(pin2.is_high());
    }

Alternative test for this case could be to use ADC with pullup/down and check voltage levels, in case the voltage was in the middle it would mean that an opposite pullup/down resistor was enabled when it shouldn't, but it would require rewiring test board and would be in my opinion a bit overkill.

Please note that I'm barely experienced in Rust and I'm an amateur in EE/embedded field so I'd advice extra caution reviewing the proposed change.

[Dirbaio]

could you make this a field in Config? this way the number of params doesn't explode and it doesn't increase verbosity for users that don't need the pull.

(yes, divmode should've been a field in config too...)

[Dirbaio]

actually no, it's better to have it separate so it's only present in the new_ constructots that use inputs, since it doesnt' make sense for outputs.

(same for divmode, that's why it was that way...)

[Dirbaio]

thank you!