From c2e244378acb5c49e91f447287888c729f5d7f79 Mon Sep 17 00:00:00 2001
From: Alexander Entinger <consulting@lxrobotics.com>
Date: Wed, 8 Feb 2023 10:24:39 +0100
Subject: [PATCH] Fix: Clean-up previous state when alternating between GPIO
 and PWM functionality. This fixes #613.

---
 cores/arduino/wiring_analog.cpp  | 11 +++++++++++
 cores/arduino/wiring_digital.cpp | 11 +++++++++++
 2 files changed, 22 insertions(+)

diff --git a/cores/arduino/wiring_analog.cpp b/cores/arduino/wiring_analog.cpp
index aec8a47d0..d11783d68 100644
--- a/cores/arduino/wiring_analog.cpp
+++ b/cores/arduino/wiring_analog.cpp
@@ -68,6 +68,17 @@ void analogWrite(pin_size_t pin, int val)
 #endif
   float percent = (float)val/(float)((1 << write_resolution)-1);
   mbed::PwmOut* pwm = digitalPinToPwm(pin);
+
+  /* Check if this pin has been previously configured as a GPIO pin.
+   * If it has, delete the GPIO allocation as well as the PWM allocation
+   * to enforce a full re-initialisation of the PWM module.
+   */
+  mbed::DigitalInOut * gpio = digitalPinToGpio(pin);
+  if ((gpio != NULL) && (pwm != NULL)) {
+    delete gpio; gpio = NULL; digitalPinToGpio(pin) = NULL;
+    delete pwm; pwm = NULL; digitalPinToPwm(pin) = NULL;
+  }
+
   if (pwm == NULL) {
     pwm = new mbed::PwmOut(digitalPinToPinName(pin));
     digitalPinToPwm(pin) = pwm;
diff --git a/cores/arduino/wiring_digital.cpp b/cores/arduino/wiring_digital.cpp
index c4fa74b0c..f20c0da0c 100644
--- a/cores/arduino/wiring_digital.cpp
+++ b/cores/arduino/wiring_digital.cpp
@@ -94,6 +94,17 @@ void digitalWrite(pin_size_t pin, PinStatus val)
     return;
   }
   mbed::DigitalInOut* gpio = digitalPinToGpio(pin);
+
+  /* Check if this pin has been previously configured as a PWM pin.
+   * If it has, delete the GPIO allocation as well as the PWM allocation
+   * to enforce a full re-initialisation of the GPIO module.
+   */
+  mbed::PwmOut * pwm = digitalPinToPwm(pin);
+  if ((gpio != NULL) && (pwm != NULL)) {
+    delete gpio; gpio = NULL; digitalPinToGpio(pin) = NULL;
+    delete pwm; pwm = NULL; digitalPinToPwm(pin) = NULL;
+  }
+
   if (gpio == NULL) {
     gpio = new mbed::DigitalInOut(digitalPinToPinName(pin), PIN_OUTPUT, PullNone, val);
     digitalPinToGpio(pin) = gpio;