Added ISR_DEFERRED option for attachInterrupt() to defer callback from ISR context

Author: hathach

changelog.md

@@ -13,7 +13,9 @@
   - InternalFS use LittleFS to manage internal flash for bonding and other user data
   - ExternalFS use fatfs to manage external spi flash (nrf52840 only) for usb msc.
 - Replace cpritnf by std printf
-- Add HwPWM3 for nRF52840
+- Added HwPWM3 for nRF52840
+- Added ISR_DEFERRED for attachInterrupt() for deferring callback from ISR context
+  - Added digital_interrupt_deferred sketch for demo
 
 ## 0.8.6
 

cores/nRF5/WInterrupts.c

@@ -31,6 +31,7 @@
 #endif
 
 static voidFuncPtr callbacksInt[NUMBER_OF_GPIO_TE];
+static bool callbackDeferred[NUMBER_OF_GPIO_TE];
 static int8_t channelMap[NUMBER_OF_GPIO_TE];
 static int enabled = 0;
 
@@ -39,6 +40,7 @@ static void __initialize()
 {
   memset(callbacksInt, 0, sizeof(callbacksInt));
   memset(channelMap, -1, sizeof(channelMap));
+  memset(callbackDeferred, 0, sizeof(callbackDeferred));
 
   NVIC_DisableIRQ(GPIOTE_IRQn);
   NVIC_ClearPendingIRQ(GPIOTE_IRQn);
@@ -65,6 +67,9 @@ int attachInterrupt(uint32_t pin, voidFuncPtr callback, uint32_t mode)
 
   pin = g_ADigitalPinMap[pin];
 
+  bool deferred = (mode & ISR_DEFERRED) ? true : false;
+  mode &= ~ISR_DEFERRED;
+
   uint32_t polarity;
 
   switch (mode) {
@@ -88,6 +93,7 @@ int attachInterrupt(uint32_t pin, voidFuncPtr callback, uint32_t mode)
     if (channelMap[ch] == -1 || (uint32_t)channelMap[ch] == pin) {
       channelMap[ch] = pin;
       callbacksInt[ch] = callback;
+      callbackDeferred[ch] = deferred;
 
       NRF_GPIOTE->CONFIG[ch] &= ~(GPIOTE_CONFIG_PSEL_Msk | GPIOTE_CONFIG_POLARITY_Msk);
       NRF_GPIOTE->CONFIG[ch] |= ((pin << GPIOTE_CONFIG_PSEL_Pos) & GPIOTE_CONFIG_PSEL_Msk) |
@@ -119,6 +125,7 @@ void detachInterrupt(uint32_t pin)
     if ((uint32_t)channelMap[ch] == pin) {
       channelMap[ch] = -1;
       callbacksInt[ch] = NULL;
+      callbackDeferred[ch] = false;
 
       NRF_GPIOTE->CONFIG[ch] &= ~GPIOTE_CONFIG_MODE_Event;
 
@@ -136,7 +143,12 @@ void GPIOTE_IRQHandler()
   for (int ch = 0; ch < NUMBER_OF_GPIO_TE; ch++) {
     if ((*(uint32_t *)((uint32_t)NRF_GPIOTE + event) == 0x1UL) && (NRF_GPIOTE->INTENSET & (1 << ch))) {
       if (channelMap[ch] != -1 && callbacksInt[ch]) {
-        callbacksInt[ch]();
+        if ( callbackDeferred[ch] )  {
+          // Adafruit defer callback to non-isr if configured so
+          ada_callback_fromISR(NULL, callbacksInt[ch]);
+        }else{
+         callbacksInt[ch]();
+        }
       }
 
     *(uint32_t *)((uint32_t)NRF_GPIOTE + event) = 0;

cores/nRF5/WInterrupts.h

@@ -31,6 +31,8 @@ extern "C" {
 #define FALLING 3
 #define RISING 4
 
+#define ISR_DEFERRED  0x0100
+
 #define DEFAULT 1
 #define EXTERNAL 0
 

keywords.txt

@@ -124,3 +124,4 @@ PIN_SPI_SCK	LITERAL1
 PIN_WIRE_SDA	LITERAL1
 PIN_WIRE_SCL	LITERAL1
 
+ISR_DEFERRED	LITERAL1

libraries/Bluefruit52Lib/examples/Hardware/digital_interrupt_deferred/digital_interrupt_deferred.ino

@@ -0,0 +1,46 @@
+/*********************************************************************
+ This is an example for our Feather Bluefruit modules
+
+ Pick one up today in the adafruit shop!
+
+ Adafruit invests time and resources providing this open source code,
+ please support Adafruit and open-source hardware by purchasing
+ products from Adafruit!
+
+ MIT license, check LICENSE for more information
+ All text above, and the splash screen below must be included in
+ any redistribution
+*********************************************************************/
+
+/*
+ * This sketch demotrate how to pass ISR_DEFFERED as additional parameter
+ * to defer callback from ISR context with attachInterrupt
+ */
+#include <Arduino.h>
+
+int interruptPin = A0;
+
+void setup()
+{
+  Serial.begin(115200);
+
+  pinMode(interruptPin, INPUT_PULLUP);
+
+  // ISR_DEFERRED flag cause the callback to be deferred from ISR context
+  // and invoked within a callback thread.
+  // It is required to use ISR_DEFERRED if callback function take long time 
+  // to run e.g Serial.print() or using any of Bluefruit API() which will
+  // potentially call rtos API
+  attachInterrupt(interruptPin, digital_callback, ISR_DEFERRED | CHANGE);
+}
+
+void loop()
+{
+  // nothing to do
+}
+
+void digital_callback(void)
+{
+  Serial.print("Pin value: ");
+  Serial.println(digitalRead(interruptPin));
+}