Add non-existent pins

Author: david-sawatzke

CHANGELOG.md

@@ -11,6 +11,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 - Support for stm32f0x1 line - @jessebraham
 - Support for HSE as a system clocksource (#25 - breaking change) - @zklapow
+- Added non-existent pins for SPI & I2C
 
 ### Changed
 

examples/unused.rs

@@ -0,0 +1,36 @@
+//! This is not intended to be used on a real system
+#![no_main]
+#![no_std]
+
+#[allow(unused)]
+use panic_halt;
+
+use stm32f0xx_hal as hal;
+
+use crate::hal::i2c::*;
+use crate::hal::prelude::*;
+use crate::hal::spi::*;
+use crate::hal::stm32;
+
+use cortex_m_rt::entry;
+#[entry]
+fn main() -> ! {
+    const MODE: Mode = Mode {
+        polarity: Polarity::IdleHigh,
+        phase: Phase::CaptureOnSecondTransition,
+    };
+
+    if let Some(p) = stm32::Peripherals::take() {
+        let rcc = p.RCC.constrain();
+        let clocks = rcc.cfgr.freeze();
+
+        let pins = unsafe { (NoSck::new(), NoMiso::new(), NoMosi::new()) };
+        let _ = Spi::spi1(p.SPI1, pins, MODE, 100_000.hz(), clocks);
+
+        let pins = unsafe { (NoScl::new(), NoSda::new()) };
+        let _ = I2c::i2c1(p.I2C1, pins, 400.khz());
+    }
+    loop {
+        continue;
+    }
+}

src/i2c.rs

@@ -132,10 +132,44 @@ pub enum Error {
     NACK,
 }
 
+/// Filler for a SDA Pin
+///
+/// Usefull if you don't want to utilize the sda pin,
+/// but a pin parameter is required
+pub struct NoSda {
+    _1: (),
+}
+
+impl NoSda {
+    /// Create a new unused pin
+    pub unsafe fn new() -> Self {
+        Self { _1: () }
+    }
+}
+
+/// Filler for a SCL Pin
+///
+/// Usefull if you don't want to utilize the scl pin,
+/// but a pin parameter is required
+pub struct NoScl {
+    _1: (),
+}
+
+impl NoScl {
+    /// Create a new unused pin
+    pub unsafe fn new() -> Self {
+        Self { _1: () }
+    }
+}
+
 macro_rules! i2c {
     ($($I2C:ident: ($i2c:ident, $i2cXen:ident, $i2cXrst:ident, $apbenr:ident, $apbrstr:ident),)+) => {
         $(
             use crate::stm32::$I2C;
+
+            impl SclPin<$I2C> for NoScl {}
+            impl SdaPin<$I2C> for NoSda {}
+
             impl<SCLPIN, SDAPIN> I2c<$I2C, SCLPIN, SDAPIN> {
                 pub fn $i2c(i2c: $I2C, pins: (SCLPIN, SDAPIN), speed: KiloHertz, rcc: &mut Rcc) -> Self
                 where

src/spi.rs

@@ -171,9 +171,58 @@ spi_pins! {
     }
 }
 
+/// Filler for a SCK pin
+///
+/// Usefull if you don't want to utilize the sck pin,
+/// but a pin parameter is required
+pub struct NoSck {
+    _1: (),
+}
+
+impl NoSck {
+    /// Create a new filler sck pin
+    pub unsafe fn new() -> Self {
+        Self { _1: () }
+    }
+}
+
+/// Filler for a MISO Pin
+///
+/// Usefull if you don't want to utilize the miso pin,
+/// but a pin parameter is required
+pub struct NoMiso {
+    _1: (),
+}
+
+impl NoMiso {
+    /// Create a new filler mosi pin
+    pub unsafe fn new() -> Self {
+        Self { _1: () }
+    }
+}
+
+/// Filler for a MOSI Pin
+///
+/// Usefull if you don't want to utilize the miso pin,
+/// but a pin parameter is required
+pub struct NoMosi {
+    _1: (),
+}
+
+impl NoMosi {
+    /// Create a new filler mosi pin
+    pub unsafe fn new() -> Self {
+        Self { _1: () }
+    }
+}
+
 macro_rules! spi {
     ($($SPI:ident: ($spi:ident, $spiXen:ident, $spiXrst:ident, $apbenr:ident, $apbrstr:ident),)+) => {
         $(
+            impl SckPin<$SPI> for NoSck {}
+            impl MisoPin<$SPI> for NoMiso {}
+            impl MosiPin<$SPI> for NoMosi {}
+
             impl<SCKPIN, MISOPIN, MOSIPIN> Spi<$SPI, SCKPIN, MISOPIN, MOSIPIN> {
                 /// Creates a new spi instance
                 pub fn $spi<F>(