Merge pull request #708 from jannic/checked-i2c-construction

Ensure that i2c pins have PullUp activated

Author: jannic

rp2040-hal/examples/i2c.rs

@@ -23,7 +23,7 @@ use hal::fugit::RateExtU32;
 // A shorter alias for the Peripheral Access Crate, which provides low-level
 // register access and a gpio related types.
 use hal::{
-    gpio::{FunctionI2C, Pin, PullUp},
+    gpio::{FunctionI2C, Pin},
     pac,
 };
 
@@ -78,8 +78,8 @@ fn main() -> ! {
     );
 
     // Configure two pins as being I²C, not GPIO
-    let sda_pin: Pin<_, FunctionI2C, PullUp> = pins.gpio18.reconfigure();
-    let scl_pin: Pin<_, FunctionI2C, PullUp> = pins.gpio19.reconfigure();
+    let sda_pin: Pin<_, FunctionI2C, _> = pins.gpio18.reconfigure();
+    let scl_pin: Pin<_, FunctionI2C, _> = pins.gpio19.reconfigure();
     // let not_an_scl_pin: Pin<_, FunctionI2C, PullUp> = pins.gpio20.reconfigure();
 
     // Create the I²C drive, using the two pre-configured pins. This will fail

rp2040-hal/src/i2c.rs

@@ -12,8 +12,8 @@
 //!
 //! let mut i2c = I2C::i2c1(
 //!     peripherals.I2C1,
-//!     pins.gpio18.into_pull_up_input().into_function(), // sda
-//!     pins.gpio19.into_pull_up_input().into_function(), // scl
+//!     pins.gpio18.reconfigure(), // sda
+//!     pins.gpio19.reconfigure(), // scl
 //!     400.kHz(),
 //!     &mut peripherals.RESETS,
 //!     125_000_000.Hz(),
@@ -47,7 +47,7 @@ use core::{marker::PhantomData, ops::Deref};
 use fugit::HertzU32;
 
 use crate::{
-    gpio::{bank0::*, pin::pin_sealed::TypeLevelPinId, AnyPin, FunctionI2c},
+    gpio::{bank0::*, pin::pin_sealed::TypeLevelPinId, AnyPin, FunctionI2c, PullUp},
     pac::{self, i2c0::RegisterBlock as I2CBlock, I2C0, I2C1, RESETS},
     resets::SubsystemReset,
     typelevel::Sealed,
@@ -327,12 +327,34 @@ macro_rules! hal {
                     system_clock: SystemF) -> Self
                 where
                     F: Into<HertzU32>,
-                    Sda: ValidPinSda<$I2CX>,
-                    Scl: ValidPinScl<$I2CX>,
+                    Sda: ValidPinSda<$I2CX> + AnyPin<Pull = PullUp>,
+                    Scl: ValidPinScl<$I2CX> + AnyPin<Pull = PullUp>,
                     SystemF: Into<HertzU32>,
                 {
                     Self::new_controller(i2c, sda_pin, scl_pin, freq.into(), resets, system_clock.into())
                 }
+
+                $crate::paste::paste! {
+                    /// Configures the I2C peripheral to work in master mode
+                    ///
+                    /// This function can be called without activating internal pull-ups on the I2C pins.
+                    /// It should only be used if external pull-ups are provided.
+                    pub fn [<$i2cX _with_external_pull_up>]<F, SystemF>(
+                        i2c: $I2CX,
+                        sda_pin: Sda,
+                        scl_pin: Scl,
+                        freq: F,
+                        resets: &mut RESETS,
+                        system_clock: SystemF) -> Self
+                    where
+                        F: Into<HertzU32>,
+                        Sda: ValidPinSda<$I2CX>,
+                        Scl: ValidPinScl<$I2CX>,
+                        SystemF: Into<HertzU32>,
+                    {
+                        Self::new_controller(i2c, sda_pin, scl_pin, freq.into(), resets, system_clock.into())
+                    }
+                }
             }
         )+
     }