1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156

use super::*;

pub type EPin<MODE> = ErasedPin<MODE>;

/// Fully erased pin
///
/// `MODE` is one of the pin modes (see [Modes](crate::gpio#modes) section).
pub struct ErasedPin<MODE> {
    // Bits 0-3: Pin, Bits 4-7: Port
    pin_port: u8,
    _mode: PhantomData<MODE>,
}

impl<MODE> fmt::Debug for ErasedPin<MODE> {
    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
        formatter.write_fmt(format_args!(
            "P({}{})<{}>",
            self.port_id(),
            self.pin_id(),
            crate::stripped_type_name::<MODE>()
        ))
    }
}

#[cfg(feature = "defmt")]
impl<MODE> defmt::Format for ErasedPin<MODE> {
    fn format(&self, f: defmt::Formatter) {
        defmt::write!(
            f,
            "P({}{})<{}>",
            self.port_id(),
            self.pin_id(),
            crate::stripped_type_name::<MODE>()
        );
    }
}

impl<MODE> PinExt for ErasedPin<MODE> {
    type Mode = MODE;

    #[inline(always)]
    fn pin_id(&self) -> u8 {
        self.pin_port & 0x0f
    }
    #[inline(always)]
    fn port_id(&self) -> u8 {
        self.pin_port >> 4
    }
}

impl<MODE> ErasedPin<MODE> {
    pub(crate) fn new(port: u8, pin: u8) -> Self {
        Self {
            pin_port: port << 4 | pin,
            _mode: PhantomData,
        }
    }

    #[inline]
    fn block(&self) -> &crate::pac::gpioa::RegisterBlock {
        // This function uses pointer arithmetic instead of branching to be more efficient

        // The logic relies on the following assumptions:
        // - GPIOA register is available on all chips
        // - all gpio register blocks have the same layout
        // - consecutive gpio register blocks have the same offset between them, namely 0x0400
        // - ErasedPin::new was called with a valid port

        // FIXME could be calculated after const_raw_ptr_to_usize_cast stabilization #51910
        const GPIO_REGISTER_OFFSET: usize = 0x0400;

        let offset = GPIO_REGISTER_OFFSET * self.port_id() as usize;
        let block_ptr =
            (crate::pac::GPIOA::ptr() as usize + offset) as *const crate::pac::gpioa::RegisterBlock;

        unsafe { &*block_ptr }
    }
}

impl<MODE> ErasedPin<Output<MODE>> {
    /// Drives the pin high
    #[inline(always)]
    pub fn set_high(&mut self) {
        // NOTE(unsafe) atomic write to a stateless register
        unsafe { self.block().bsrr.write(|w| w.bits(1 << self.pin_id())) };
    }

    /// Drives the pin low
    #[inline(always)]
    pub fn set_low(&mut self) {
        // NOTE(unsafe) atomic write to a stateless register
        unsafe {
            self.block()
                .bsrr
                .write(|w| w.bits(1 << (self.pin_id() + 16)))
        };
    }

    /// Is the pin in drive high or low mode?
    #[inline(always)]
    pub fn get_state(&self) -> PinState {
        if self.is_set_low() {
            PinState::Low
        } else {
            PinState::High
        }
    }

    /// Drives the pin high or low depending on the provided value
    #[inline(always)]
    pub fn set_state(&mut self, state: PinState) {
        match state {
            PinState::Low => self.set_low(),
            PinState::High => self.set_high(),
        }
    }

    /// Is the pin in drive high mode?
    #[inline(always)]
    pub fn is_set_high(&self) -> bool {
        !self.is_set_low()
    }

    /// Is the pin in drive low mode?
    #[inline(always)]
    pub fn is_set_low(&self) -> bool {
        self.block().odr.read().bits() & (1 << self.pin_id()) == 0
    }

    /// Toggle pin output
    #[inline(always)]
    pub fn toggle(&mut self) {
        if self.is_set_low() {
            self.set_high()
        } else {
            self.set_low()
        }
    }
}

impl<MODE> ErasedPin<MODE>
where
    MODE: marker::Readable,
{
    /// Is the input pin high?
    #[inline(always)]
    pub fn is_high(&self) -> bool {
        !self.is_low()
    }

    /// Is the input pin low?
    #[inline(always)]
    pub fn is_low(&self) -> bool {
        self.block().idr.read().bits() & (1 << self.pin_id()) == 0
    }
}