From 3ec4e6320a3e9f7723a91e727004a35c3c903765 Mon Sep 17 00:00:00 2001
From: Jonathan Dickinson <oss@jonathan.dickinson.id>
Date: Tue, 10 Oct 2023 20:14:09 -0400
Subject: [PATCH] fix (rp i2c): set i2c slew rate to spec value

The RP2040 datasheet indicates that I2C pins should have a limited
slew rate (Page 440 - 4.3.1.3.). This configures that for both
`I2c` and `I2cSlave`.

In addition, the pin configuration has been centralized to a single
fn.
---
 embassy-rp/src/i2c.rs       | 36 ++++++++++++++++++------------------
 embassy-rp/src/i2c_slave.rs | 23 +++++------------------
 2 files changed, 23 insertions(+), 36 deletions(-)

diff --git a/embassy-rp/src/i2c.rs b/embassy-rp/src/i2c.rs
index 77777ad3..b4036f20 100644
--- a/embassy-rp/src/i2c.rs
+++ b/embassy-rp/src/i2c.rs
@@ -6,7 +6,6 @@ use embassy_hal_internal::{into_ref, PeripheralRef};
 use embassy_sync::waitqueue::AtomicWaker;
 use pac::i2c;
 
-use crate::gpio::sealed::Pin;
 use crate::gpio::AnyPin;
 use crate::interrupt::typelevel::{Binding, Interrupt};
 use crate::{interrupt, pac, peripherals, Peripheral};
@@ -318,6 +317,22 @@ impl<T: Instance> interrupt::typelevel::Handler<T::Interrupt> for InterruptHandl
     }
 }
 
+pub(crate) fn set_up_i2c_pin<'d, P, T>(pin: &P)
+where
+    P: core::ops::Deref<Target = T>,
+    T: crate::gpio::Pin,
+{
+    pin.gpio().ctrl().write(|w| w.set_funcsel(3));
+    pin.pad_ctrl().write(|w| {
+        w.set_schmitt(true);
+        w.set_slewfast(false);
+        w.set_ie(true);
+        w.set_od(false);
+        w.set_pue(true);
+        w.set_pde(false);
+    });
+}
+
 impl<'d, T: Instance + 'd, M: Mode> I2c<'d, T, M> {
     fn new_inner(
         _peri: impl Peripheral<P = T> + 'd,
@@ -355,23 +370,8 @@ impl<'d, T: Instance + 'd, M: Mode> I2c<'d, T, M> {
         p.ic_rx_tl().write(|w| w.set_rx_tl(0));
 
         // Configure SCL & SDA pins
-        scl.gpio().ctrl().write(|w| w.set_funcsel(3));
-        sda.gpio().ctrl().write(|w| w.set_funcsel(3));
-
-        scl.pad_ctrl().write(|w| {
-            w.set_schmitt(true);
-            w.set_ie(true);
-            w.set_od(false);
-            w.set_pue(true);
-            w.set_pde(false);
-        });
-        sda.pad_ctrl().write(|w| {
-            w.set_schmitt(true);
-            w.set_ie(true);
-            w.set_od(false);
-            w.set_pue(true);
-            w.set_pde(false);
-        });
+        set_up_i2c_pin(&scl);
+        set_up_i2c_pin(&sda);
 
         // Configure baudrate
 
diff --git a/embassy-rp/src/i2c_slave.rs b/embassy-rp/src/i2c_slave.rs
index 30e78925..9271ede3 100644
--- a/embassy-rp/src/i2c_slave.rs
+++ b/embassy-rp/src/i2c_slave.rs
@@ -5,7 +5,9 @@ use core::task::Poll;
 use embassy_hal_internal::into_ref;
 use pac::i2c;
 
-use crate::i2c::{i2c_reserved_addr, AbortReason, Instance, InterruptHandler, SclPin, SdaPin, FIFO_SIZE};
+use crate::i2c::{
+    i2c_reserved_addr, set_up_i2c_pin, AbortReason, Instance, InterruptHandler, SclPin, SdaPin, FIFO_SIZE,
+};
 use crate::interrupt::typelevel::{Binding, Interrupt};
 use crate::{pac, Peripheral};
 
@@ -100,23 +102,8 @@ impl<'d, T: Instance> I2cSlave<'d, T> {
         p.ic_rx_tl().write(|w| w.set_rx_tl(0));
 
         // Configure SCL & SDA pins
-        scl.gpio().ctrl().write(|w| w.set_funcsel(3));
-        sda.gpio().ctrl().write(|w| w.set_funcsel(3));
-
-        scl.pad_ctrl().write(|w| {
-            w.set_schmitt(true);
-            w.set_ie(true);
-            w.set_od(false);
-            w.set_pue(true);
-            w.set_pde(false);
-        });
-        sda.pad_ctrl().write(|w| {
-            w.set_schmitt(true);
-            w.set_ie(true);
-            w.set_od(false);
-            w.set_pue(true);
-            w.set_pde(false);
-        });
+        set_up_i2c_pin(&scl);
+        set_up_i2c_pin(&sda);
 
         // Clear interrupts
         p.ic_clr_intr().read();