diff --git a/VERSION b/VERSION
index 5174c53..b2fb78a 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-3.16
+3.18
diff --git a/documentation/deutsch/functions.md b/documentation/deutsch/functions.md
index 0c86b55..f0c87b3 100644
--- a/documentation/deutsch/functions.md
+++ b/documentation/deutsch/functions.md
@@ -473,7 +473,7 @@ static void wfi(struct WPIWfiStatus wfiStatus, void* userdata) {
       edgeType = "falling";
   else
       edgeType = "none";
-  printf("gpio BCM = %d, IRQ edge = %s, timestamp = %lld microseconds, timenow = %lld, diff = %lld\n", wfiStatus.gpioPin, edgeType, wfiStatus.timeStamp_us, timenow, diff);
+  printf("gpio BCM = %d, IRQ edge = %s, timestamp = %lld microseconds, timenow = %lld, diff = %lld\n", wfiStatus.pinBCM, edgeType, wfiStatus.timeStamp_us, timenow, diff);
   if (toggle == 0) {
     digitalWrite (OUTpin, HIGH);
     toggle = 1;
@@ -500,19 +500,19 @@ int main (void)
 
   printf("Testing waitForInterrupt on both edges IRQ @ GPIO%d, timeout is %d\n", IRQpin, TIMEOUT);
   struct WPIWfiStatus wfiStatus = waitForInterrupt2(IRQpin, INT_EDGE_BOTH, TIMEOUT, BOUNCETIME_WFI);
-  if (wfiStatus.status < 0) {
+  if (wfiStatus.statusOK < 0) {
     printf("waitForInterrupt returned error\n");
     pinMode(OUTpin, INPUT);
     return 0;
   }
-  else if (wfiStatus.status == 0) {
+  else if (wfiStatus.statusOK == 0) {
     printf("waitForInterrupt timed out\n\n");
   }
   else {
     if (wfiStatus.edge == INT_EDGE_FALLING)
-        printf("waitForInterrupt: GPIO pin %d falling edge fired at %lld microseconds\n\n", wfiStatus.gpioPin, wfiStatus.timeStamp_us);
+        printf("waitForInterrupt: GPIO pin %d falling edge fired at %lld microseconds\n\n", wfiStatus.pinBCM, wfiStatus.timeStamp_us);
     else
-        printf("waitForInterrupt: GPIO pin %d rising edge fired at %lld microseconds\n\n", wfiStatus.gpioPin, wfiStatus.timeStamp_us);
+        printf("waitForInterrupt: GPIO pin %d rising edge fired at %lld microseconds\n\n", wfiStatus.pinBCM, wfiStatus.timeStamp_us);
   }
   
   printf("Testing IRQ @ GPIO%d on both edges and bouncetime %d microseconds. Toggle LED @ GPIO%d on IRQ.\n\n", IRQpin, BOUNCETIME, OUTpin);
@@ -809,8 +809,8 @@ int wiringPiSPISetupMode(int channel, int speed, int mode)
 int wiringPiSPIxSetupMode(const int number, const int channel, const int speed, const int mode)
 ```
 
-``number``: SPI Nummer (typisch 0, bei Compute Modul 0-7).  
-``channel``: SPI Kanal (typisch 0 oder 1, bei Compute Modul 0-3).  
+``number``: SPI Nummer (typisch 0, bei Compute Modul 0-6).  
+``channel``: SPI Kanal (typisch 0 oder 1, bei Compute Modul oder entsprechenden overlay 0-4).  
 ``speed``: SPI Taktrate.  
 ``mode``: SPI Modus (https://www.kernel.org/doc/Documentation/spi/spidev).  
 ``Rückgabewert``:  Datei Handle zum SPI-Bus  
diff --git a/documentation/english/functions.md b/documentation/english/functions.md
index f13874a..f1ec746 100644
--- a/documentation/english/functions.md
+++ b/documentation/english/functions.md
@@ -470,7 +470,7 @@ static void wfi(struct WPIWfiStatus wfiStatus, void* userdata) {
       edgeType = "falling";
   else
       edgeType = "none";
-  printf("gpio BCM = %d, IRQ edge = %s, timestamp = %lld microseconds, timenow = %lld, diff = %lld\n", wfiStatus.gpioPin, edgeType, wfiStatus.timeStamp_us, timenow, diff);
+  printf("gpio BCM = %d, IRQ edge = %s, timestamp = %lld microseconds, timenow = %lld, diff = %lld\n", wfiStatus.pinBCM, edgeType, wfiStatus.timeStamp_us, timenow, diff);
   if (toggle == 0) {
     digitalWrite (OUTpin, HIGH);
     toggle = 1;
@@ -497,19 +497,19 @@ int main (void)
 
   printf("Testing waitForInterrupt on both edges IRQ @ GPIO%d, timeout is %d\n", IRQpin, TIMEOUT);
   struct WPIWfiStatus wfiStatus = waitForInterrupt2(IRQpin, INT_EDGE_BOTH, TIMEOUT, BOUNCETIME_WFI);
-  if (wfiStatus.status < 0) {
+  if (wfiStatus.statusOK < 0) {
     printf("waitForInterrupt returned error\n");
     pinMode(OUTpin, INPUT);
     return 0;
   }
-  else if (wfiStatus.status == 0) {
+  else if (wfiStatus.statusOK == 0) {
     printf("waitForInterrupt timed out\n\n");
   }
   else {
     if (wfiStatus.edge == INT_EDGE_FALLING)
-        printf("waitForInterrupt: GPIO pin %d falling edge fired at %lld microseconds\n\n", wfiStatus.gpioPin, wfiStatus.timeStamp_us);
+        printf("waitForInterrupt: GPIO pin %d falling edge fired at %lld microseconds\n\n", wfiStatus.pinBCM, wfiStatus.timeStamp_us);
     else
-        printf("waitForInterrupt: GPIO pin %d rising edge fired at %lld microseconds\n\n", wfiStatus.gpioPin, wfiStatus.timeStamp_us);
+        printf("waitForInterrupt: GPIO pin %d rising edge fired at %lld microseconds\n\n", wfiStatus.pinBCM, wfiStatus.timeStamp_us);
   }
 
   printf("Testing IRQ @ GPIO%d on both edges and bouncetime %d microseconds. Toggle LED @ GPIO%d on IRQ.\n\n", IRQpin, BOUNCETIME, OUTpin);
@@ -798,8 +798,8 @@ int wiringPiSPISetupMode(int channel, int speed, int mode);
 int wiringPiSPIxSetupMode(const int number, const int channel, const int speed, const int mode);
 ```
 
-``number``: SPI number (typically 0, on Compute Module 0-7).  
-``channel``: SPI channel (typically 0 or 1, on Compute Module 0-3).  
+``number``: SPI number (typically 0, on Compute Module 0-6).  
+``channel``: SPI channel (typically 0 or 1, on Compute Module or the corresponding overlay 0-4).  
 ``speed``: SPI clock speed in Hz (500,000 to 32,000,000).  
 ``mode``: SPI mode ([www.kernel.org/doc/Documentation/spi/spidev](https://www.kernel.org/doc/Documentation/spi/spidev)).  
 ``Return Value``:  File handle to the SPI bus, or -1 on error.
diff --git a/gpio/gpio.1 b/gpio/gpio.1
index 4d76671..e99b66a 100644
--- a/gpio/gpio.1
+++ b/gpio/gpio.1
@@ -282,7 +282,7 @@ Please report bugs to https://github.com/WiringPi/WiringPi/issues
 
 .SH COPYRIGHT
 
-Copyright (c) 2012-2025 Gordon Henderson and contributors
+Copyright (c) 2012–2019 Gordon Henderson; 2019–2026 Contributors
 .br
 This is free software; see the source for copying conditions. There is NO
 warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
diff --git a/gpio/gpio.c b/gpio/gpio.c
index 8eae4d1..bf7d23d 100644
--- a/gpio/gpio.c
+++ b/gpio/gpio.c
@@ -2,7 +2,7 @@
  * gpio.c:
  *	Swiss-Army-Knife, Set-UID command-line interface to the Raspberry
  *	Pi's GPIO.
- *	Copyright (c) 2012-2025 Gordon Henderson and contributors
+ *	Copyright (c) 2012–2019 Gordon Henderson; 2019–2026 Contributors
  ***********************************************************************
  * This file is part of wiringPi:
  *	https://github.com/WiringPi/WiringPi/
@@ -916,7 +916,7 @@ static void doVersion (char *argv [])
 
   wiringPiVersion (&vMaj, &vMin) ;
   printf ("gpio version: %d.%d\n", vMaj, vMin) ;
-  printf ("Copyright (c) 2012-2025 Gordon Henderson and contributors\n") ;
+  printf ("Copyright (c) 2012–2019 Gordon Henderson; 2019–2026 Contributors\n") ;
   printf ("This is free software with ABSOLUTELY NO WARRANTY.\n") ;
   printf ("For details type: %s -warranty\n", argv [0]) ;
   printf ("\n") ;
@@ -1033,7 +1033,7 @@ int main (int argc, char *argv [])
   if (strcasecmp (argv [1], "-warranty") == 0)
   {
     printf ("gpio version: %s\n", VERSION) ;
-    printf ("Copyright (c) 2012-2025 Gordon Henderson and contributors\n") ;
+    printf ("Copyright (c) 2012–2019 Gordon Henderson; 2019–2026 Contributors\n") ;
     printf ("\n") ;
     printf ("    This program is free software; you can redistribute it and/or modify\n") ;
     printf ("    it under the terms of the GNU Leser General Public License as published\n") ;
diff --git a/gpio/readall.c b/gpio/readall.c
index 3812e53..d75c414 100644
--- a/gpio/readall.c
+++ b/gpio/readall.c
@@ -1,7 +1,7 @@
 /*
  * readall.c:
  *	The readall functions - getting a bit big, so split them out.
- *	Copyright (c) 2012-2024 Gordon Henderson and contributors
+ *	Copyright (c) 2012–2019 Gordon Henderson; 2019–2026 Contributors
  ***********************************************************************
  * This file is part of wiringPi:
  *	https://github.com/WiringPi/WiringPi/
diff --git a/gpio/test/gpio_test1_piface1.sh b/gpio/test/gpio_test1_piface1.sh
new file mode 100755
index 0000000..5840830
--- /dev/null
+++ b/gpio/test/gpio_test1_piface1.sh
@@ -0,0 +1,90 @@
+#!/bin/bash
+
+echo -e "🔧 Starting relay unit test for MCP23S17@Piface unit test hw\n\n"
+
+# set pin 200–207 as output
+for i in {200..207}; do
+  gpio -x mcp23s17:200:0:0 mode $i out
+done
+
+# set pin 208–215 as input
+for i in {208..215}; do
+  gpio -x mcp23s17:200:0:0 mode $i in
+  gpio -x mcp23s17:200:0:0 mode $i up
+done
+
+
+# Define relay output addresses and corresponding feedback input addresses
+relay_addresses=(200 201 207 206)
+feedback_addresses=(214 215 212 213)
+
+for round in {1..3}; do
+echo -e "🔄 Round $round / 3\n"
+
+# Loop through each relay
+for i in "${!relay_addresses[@]}"; do
+    out=${relay_addresses[$i]}
+    in=${feedback_addresses[$i]}
+
+    echo "➡️  Relay/IO write test $((i+1)): Address $out → Feedback at $in"
+
+    # Turn ON
+    gpio -x mcp23s17:200:0:0 write "$out" 1
+    sleep 0.5
+    feedback_on=$(gpio -x mcp23s17:200:0:0 read "$in")
+
+    if [ "$feedback_on" -eq 0 ]; then
+        echo "✅ ON Test passed: Feedback is LOW as expected."
+    else
+        echo "❌ ON Test failed: Feedback is HIGH."
+    fi
+
+    # Turn OFF
+    gpio -x mcp23s17:200:0:0 write "$out" 0
+    sleep 0.5
+    feedback_off=$(gpio -x mcp23s17:200:0:0 read "$in")
+
+    if [ "$feedback_off" -eq 1 ]; then
+        echo "✅ OFF Test passed: Feedback is HIGH as expected."
+    else
+        echo "❌ OFF Test failed: Feedback is LOW."
+    fi
+
+    echo -e "\n"
+    sleep 0.5
+
+done
+    for addr in {208..211}; do
+
+    echo "🔃 Pullup resistor test address $addr: "
+     gpio -x mcp23s17:200:0:0 mode "$addr" up
+    sleep 0.5
+     feedback_on=$(gpio -x mcp23s17:200:0:0 read "$addr")
+
+    if [ "$feedback_on" -eq 1 ]; then
+        echo "✅ PULLUP Test passed: Feedback is HIGH as expected."
+    else
+        echo "❌ PULLUP Test failed: Feedback is LOW."
+    fi
+    sleep 0.5
+ 
+     gpio -x mcp23s17:200:0:0 mode "$addr" down 
+    sleep 0.5
+     feedback_on=$(gpio -x mcp23s17:200:0:0 read "$addr")
+
+    if [ "$feedback_on" -eq 1 ]; then
+        echo "✅ PULLDOWN Test passed: Feedback is LOW as expected."
+    else
+        echo "❌ PULLDOW Test failed: Feedback is HIGH."
+    fi
+
+    echo -e "\n"
+    sleep 0.5
+
+
+done
+
+done
+
+#echo "🧹 Cleanup complete. All relays turned OFF."
+
diff --git a/version.h b/version.h
index 5ea1e8c..5d9ebc5 100644
--- a/version.h
+++ b/version.h
@@ -1,3 +1,3 @@
-#define VERSION "3.16"
+#define VERSION "3.18"
 #define VERSION_MAJOR 3
-#define VERSION_MINOR 16
+#define VERSION_MINOR 18
diff --git a/wiringPi/gtest/.gitignore b/wiringPi/gtest/.gitignore
new file mode 100644
index 0000000..b868581
--- /dev/null
+++ b/wiringPi/gtest/.gitignore
@@ -0,0 +1,2 @@
+bin
+googletest-main
diff --git a/wiringPi/gtest/Makefile b/wiringPi/gtest/Makefile
new file mode 100644
index 0000000..16ce2f8
--- /dev/null
+++ b/wiringPi/gtest/Makefile
@@ -0,0 +1,92 @@
+CXX      := g++
+CXXFLAGS := -std=c++17 -Wall -Wextra -Werror -g \
+	-Igoogletest-main/googletest/include -Igoogletest-main/googlemock/include
+LDFLAGS  := -pthread
+WIRING_PI_LIBS := -lwiringPi
+
+# Where to download googletest
+GTEST_URL := https://github.com/google/googletest/archive/refs/heads/main.zip
+GTEST_ZIP := googletest.zip
+GTEST_DIR := googletest-main
+
+# Output directory
+BIN_DIR := bin
+
+# Helper program
+RUN_ISR_SRC := run_isr.cpp
+RUN_ISR_BIN := $(BIN_DIR)/run_isr
+
+# Need BCM17 <-> BCM18 connection
+TEST_SRCS := \
+    test_isr_both.cpp \
+    test_isr_conflict_between_processes.cpp \
+    test_isr_falling.cpp \
+    test_isr_restart.cpp \
+    test_isr_restart2.cpp \
+    test_isr_rising.cpp \
+    test_isr_rising2.cpp
+
+# Derive test binaries (in bin/)
+TEST_BINS := $(addprefix $(BIN_DIR)/, $(TEST_SRCS:.cpp=))
+
+# gtest/gmock sources
+GTEST_SRCS := $(GTEST_DIR)/googletest/src/gtest-all.cc
+GMOCK_SRCS := $(GTEST_DIR)/googlemock/src/gmock-all.cc
+GTEST_MAIN := $(GTEST_DIR)/googletest/src/gtest_main.cc
+GTEST_INCLUDES := -I$(GTEST_DIR)/googletest/include -I$(GTEST_DIR)/googlemock/include
+
+GTEST_OBJS := $(GTEST_SRCS:.cc=.o)
+GMOCK_OBJS := $(GMOCK_SRCS:.cc=.o)
+GTEST_MAIN_OBJ := $(GTEST_MAIN:.cc=.o)
+
+# Default: build everything
+all: $(GTEST_DIR) $(BIN_DIR) $(TEST_BINS) $(RUN_ISR_BIN)
+
+# Rule: build normal test binaries
+$(filter-out $(BIN_DIR)/test_conflict_between_processes,$(TEST_BINS)): $(BIN_DIR)/%: %.cpp $(GTEST_OBJS) $(GMOCK_OBJS) $(GTEST_MAIN_OBJ)
+	$(CXX) $(CXXFLAGS) $< $(GTEST_OBJS) $(GMOCK_OBJS) $(GTEST_MAIN_OBJ) -o $@ $(LDFLAGS) $(WIRING_PI_LIBS)
+
+# Special case: test_conflict_between_processes depends on run_isr
+$(BIN_DIR)/test_conflict_between_processes: test_conflict_between_processes.cpp $(GTEST_OBJS) $(GMOCK_OBJS) $(GTEST_MAIN_OBJ) $(RUN_ISR_BIN)
+	$(CXX) $(CXXFLAGS) $< $(GTEST_OBJS) $(GMOCK_OBJS) $(GTEST_MAIN_OBJ) -o $@ $(LDFLAGS) $(WIRING_PI_LIBS)
+
+# Build run_isr
+$(RUN_ISR_BIN): $(RUN_ISR_SRC) | $(BIN_DIR)
+	$(CXX) $(CXXFLAGS) $< -o $@ $(WIRING_PI_LIBS)
+
+# Ensure bin directory exists
+$(BIN_DIR):
+	mkdir -p $(BIN_DIR)
+
+# Download googletest if not already present
+$(GTEST_DIR):
+	@echo "Downloading GoogleTest..."
+	curl -L $(GTEST_URL) -o $(GTEST_ZIP)
+	unzip -q $(GTEST_ZIP)
+	rm -f $(GTEST_ZIP)
+
+# Generic rules for compiling gtest/gmock sources
+%.o: %.cc
+	$(CXX) $(CXXFLAGS) $(GTEST_INCLUDES) -I$(GTEST_DIR)/googletest -I$(GTEST_DIR)/googlemock -c $< -o $@
+
+# Run all tests
+test: all
+	@failed=0; \
+	for t in $(TEST_BINS); do \
+	    echo "Running $$t..."; \
+	    ./$$t || failed=1; \
+	done; \
+	if [ $$failed -eq 0 ]; then \
+	    echo "✅ All tests passed."; \
+	else \
+	    echo "❌ Some tests failed."; \
+	    exit 1; \
+	fi
+
+clean:
+	rm -f $(TEST_BINS) $(RUN_ISR_BIN)
+
+distclean: clean
+	rm -rf $(GTEST_DIR) $(BIN_DIR)
+
+.PHONY: all clean distclean test
\ No newline at end of file
diff --git a/wiringPi/gtest/README.md b/wiringPi/gtest/README.md
new file mode 100644
index 0000000..b061c05
--- /dev/null
+++ b/wiringPi/gtest/README.md
@@ -0,0 +1,26 @@
+## Quick Start
+
+g++ is required to build the test cases.
+
+Connect wPi pin 1 (BCM 18) and wPi pin 0 (BCM 17) to run ISR tests.
+Also, wPi pin 6 (BCM 25) should be unconnected.
+
+Run `make test` or do following to run the test:
+
+```
+make googletest-main
+make -j 4
+make test
+```
+
+To clean up the environment:
+
+```
+make clean
+```
+
+## Dependencies
+
+Googletest is downloaded during
+the build for the first time. The downloaded items are in directory `googletest-main`. `make clean` keeps this directory.  Run `make distclean`
+to erase all built images including googletest.
diff --git a/wiringPi/gtest/run_isr.cpp b/wiringPi/gtest/run_isr.cpp
new file mode 100644
index 0000000..9937946
--- /dev/null
+++ b/wiringPi/gtest/run_isr.cpp
@@ -0,0 +1,31 @@
+/*
+ * Helper program of test_conflict_between_processes.
+ *
+ * The program configures ISR on pin 1 (BCM 18) and polls for a termination request.
+ */
+#include <stdint.h>
+#include <stdio.h>
+#include <wiringPi.h>
+
+#define LISTENER_PIN 1  // BCM 18
+
+static uint8_t ok_to_stop = 0;
+static void noop() {
+  fprintf(stderr, "interrupted\n");
+  ok_to_stop = 1;
+}
+
+int main(int, char *[]) {
+  fprintf(stderr, "start\n");
+  wiringPiSetup();
+  if (wiringPiISR(LISTENER_PIN, INT_EDGE_RISING, noop)) {
+    fprintf(stderr, "failed to start listener\n");
+    return -1;
+  }
+  fprintf(stderr, "start listening\n");
+
+  while (!ok_to_stop) {
+    delay(1000);
+  }
+  fprintf(stderr, "bye\n");
+}
\ No newline at end of file
diff --git a/wiringPi/gtest/test_isr_both.cpp b/wiringPi/gtest/test_isr_both.cpp
new file mode 100644
index 0000000..a404e73
--- /dev/null
+++ b/wiringPi/gtest/test_isr_both.cpp
@@ -0,0 +1,51 @@
+#include <gtest/gtest.h>
+#include <time.h>
+#include <wiringPi.h>
+
+#define TRIGGER_PIN  0  // BCM 17
+#define LISTENER_PIN 1  // BCM 18
+
+/**
+ * Tests ISR for both edges.
+ */
+class ISRBoth : public ::testing::Test {
+ public:
+  static void SetUpTestSuite() {
+    wiringPiSetup();
+    pinMode(TRIGGER_PIN, OUTPUT);
+    digitalWrite(TRIGGER_PIN, LOW);
+    wiringPiISR(LISTENER_PIN, INT_EDGE_BOTH, ISRBoth::TriggerCount);
+    delay(100);
+  }
+
+  static uint32_t count;
+  static void TriggerCount() { ++count; }
+
+ protected:
+  virtual void SetUp() { count = 0; }
+
+  virtual void TearDown() {
+    digitalWrite(TRIGGER_PIN, LOW);
+    delay(10);
+  }
+};
+
+uint32_t ISRBoth::count = 0;
+
+TEST_F(ISRBoth, Fundamental) {
+  EXPECT_EQ(count, 0u);
+  digitalWrite(TRIGGER_PIN, HIGH);
+  delay(10);
+  EXPECT_EQ(count, 1u);
+  digitalWrite(TRIGGER_PIN, LOW);
+  delay(10);
+  EXPECT_EQ(count, 2u);
+}
+
+TEST_F(ISRBoth, ThreeTriggers) {
+  for (int i = 0; i < 5; ++i) {
+    digitalWrite(TRIGGER_PIN, (i + 1) % 2);
+    delay(10);
+  }
+  EXPECT_EQ(count, 5u);
+}
\ No newline at end of file
diff --git a/wiringPi/gtest/test_isr_conflict_between_processes.cpp b/wiringPi/gtest/test_isr_conflict_between_processes.cpp
new file mode 100644
index 0000000..2ac955c
--- /dev/null
+++ b/wiringPi/gtest/test_isr_conflict_between_processes.cpp
@@ -0,0 +1,68 @@
+#include <gtest/gtest.h>
+#include <pthread.h>
+#include <stdio.h>
+#include <time.h>
+#include <unistd.h>
+#include <wiringPi.h>
+
+#define TRIGGER_PIN  0  // BCM 17
+#define LISTENER_PIN 1  // BCM 18
+#define ANOTHER_LISTENER_PIN 6  // BCM 25
+
+static void *remote_isr(void *) {
+  std::system("./bin/run_isr");
+  return NULL;
+}
+
+/**
+ * Tests ISR setup conflict between two processes.
+ *
+ * Another program 'run_isr' starts first that occupies the pin 31 for an ISR.
+ * This program should fail to start ISR on the same pin.
+ */
+class ISRConflict : public ::testing::Test {
+ public:
+  static void SetUpTestSuite() {
+    wiringPiSetup();
+    digitalWrite(TRIGGER_PIN, LOW);
+
+    pthread_t tid;
+    pthread_create(&tid, NULL, remote_isr, NULL);
+    delay(1000);
+  }
+
+  static void TearDownTestSuite() {
+      delay(1000);
+  }
+
+  static uint32_t count;
+
+  static void TriggerCount() { ++count; }
+  static void TriggerCount2(WPIWfiStatus, void *userdata) {
+    ++*(uint32_t *)userdata;
+  }
+
+ protected:
+  virtual void SetUp() { count = 0; }
+
+  virtual void TearDown() {
+    digitalWrite(TRIGGER_PIN, LOW);
+    delay(10);
+  }
+};
+
+uint32_t ISRConflict::count = 0;
+
+TEST_F(ISRConflict, TestConflictBetweenProcesses) {
+  // The ISRs should fail to start because run_isr is listening on the
+  // same port
+  EXPECT_EQ(
+      wiringPiISR(LISTENER_PIN, INT_EDGE_FALLING, ISRConflict::TriggerCount),
+      -1);
+  EXPECT_EQ(wiringPiISR2(LISTENER_PIN, INT_EDGE_FALLING,
+                         ISRConflict::TriggerCount2, 0, &ISRConflict::count),
+            -1);
+
+  // to exit run_isr
+  digitalWrite(TRIGGER_PIN, HIGH);
+}
diff --git a/wiringPi/gtest/test_isr_falling.cpp b/wiringPi/gtest/test_isr_falling.cpp
new file mode 100644
index 0000000..ee52e6a
--- /dev/null
+++ b/wiringPi/gtest/test_isr_falling.cpp
@@ -0,0 +1,57 @@
+#include <gtest/gtest.h>
+#include <time.h>
+#include <wiringPi.h>
+
+#define TRIGGER_PIN  0  // BCM 17
+#define LISTENER_PIN 1  // BCM 18
+
+/**
+ * Tests ISR for falling edges.
+ */
+class ISRFalling : public ::testing::Test {
+ public:
+  static void SetUpTestSuite() {
+    wiringPiSetup();
+    pinMode(TRIGGER_PIN, OUTPUT);
+    digitalWrite(TRIGGER_PIN, HIGH);
+    wiringPiISR(LISTENER_PIN, INT_EDGE_FALLING, ISRFalling::TriggerCount);
+    delay(100);
+  }
+
+  static void TearDownTestSuite() { digitalWrite(TRIGGER_PIN, LOW); }
+
+  static uint32_t count;
+  static void TriggerCount() { ++count; }
+
+ protected:
+  virtual void SetUp() { count = 0; }
+
+  virtual void TearDown() {
+    digitalWrite(TRIGGER_PIN, HIGH);
+    delay(10);
+  }
+};
+
+uint32_t ISRFalling::count = 0;
+
+TEST_F(ISRFalling, Fundamental) {
+  EXPECT_EQ(count, 0u);
+  digitalWrite(TRIGGER_PIN, LOW);
+  delay(10);
+  EXPECT_EQ(count, 1u);
+  digitalWrite(TRIGGER_PIN, HIGH);
+  delay(10);
+  EXPECT_EQ(count, 1u);
+}
+
+TEST_F(ISRFalling, ThreeTriggers) {
+  digitalWrite(TRIGGER_PIN, LOW);
+  delay(10);
+  count = 0;
+  for (int i = 0; i < 6; ++i) {
+    delay(10);
+    digitalWrite(TRIGGER_PIN, (i + 1) % 2);
+  }
+  delay(10);
+  EXPECT_EQ(count, 3u);
+}
\ No newline at end of file
diff --git a/wiringPi/gtest/test_isr_restart.cpp b/wiringPi/gtest/test_isr_restart.cpp
new file mode 100644
index 0000000..29c2f79
--- /dev/null
+++ b/wiringPi/gtest/test_isr_restart.cpp
@@ -0,0 +1,68 @@
+#include <gtest/gtest.h>
+#include <time.h>
+#include <wiringPi.h>
+
+#define TRIGGER_PIN  0  // BCM 17
+#define LISTENER_PIN 1  // BCM 18
+#define ANOTHER_LISTENER_PIN 6  // BCM 25
+
+/**
+ * Tests restarting ISR.
+ */
+class ISRRestart : public ::testing::Test {
+ public:
+  static void SetUpTestSuite() {
+    wiringPiSetup();
+    pinMode(TRIGGER_PIN, OUTPUT);
+    digitalWrite(TRIGGER_PIN, LOW);
+    wiringPiISR(LISTENER_PIN, INT_EDGE_RISING, ISRRestart::TriggerCount);
+    delay(100);
+  }
+
+  static uint32_t count;
+
+  static void TriggerCount() { ++count; }
+
+  static void TriggerCountDown() { --count; }
+
+ protected:
+  virtual void SetUp() { count = 0; }
+
+  virtual void TearDown() {
+    digitalWrite(TRIGGER_PIN, LOW);
+    delay(10);
+  }
+};
+
+uint32_t ISRRestart::count = 0;
+
+TEST_F(ISRRestart, RestartISR) {
+  // fundamental ISR test
+  EXPECT_EQ(count, 0u);
+  digitalWrite(TRIGGER_PIN, HIGH);
+  delay(10);
+  EXPECT_EQ(count, 1u);
+  digitalWrite(TRIGGER_PIN, LOW);
+  delay(10);
+  EXPECT_EQ(count, 1u);
+
+  // stop the ISR
+  EXPECT_EQ(wiringPiISRStop(LISTENER_PIN), 0);
+  digitalWrite(TRIGGER_PIN, HIGH);
+  delay(10);
+  EXPECT_EQ(count, 1u);
+  digitalWrite(TRIGGER_PIN, LOW);
+
+  // start another ISR on the same pin
+  EXPECT_EQ(
+      wiringPiISR(LISTENER_PIN, INT_EDGE_FALLING, ISRRestart::TriggerCountDown),
+      0);
+  count=1;
+  delay(100);
+  digitalWrite(TRIGGER_PIN, HIGH);
+  delay(10);
+  EXPECT_EQ(count, 1u);
+  digitalWrite(TRIGGER_PIN, LOW);
+  delay(10);
+  EXPECT_EQ(count, 0u);
+}
diff --git a/wiringPi/gtest/test_isr_restart2.cpp b/wiringPi/gtest/test_isr_restart2.cpp
new file mode 100644
index 0000000..df2ca5e
--- /dev/null
+++ b/wiringPi/gtest/test_isr_restart2.cpp
@@ -0,0 +1,109 @@
+#include <gtest/gtest.h>
+#include <time.h>
+#include <wiringPi.h>
+
+#define TRIGGER_PIN  0  // BCM 17
+#define LISTENER_PIN 1  // BCM 18
+#define ANOTHER_LISTENER_PIN 26  // BCM 12
+
+struct counters {
+  int32_t *primary;
+  int32_t *secondary;
+};
+
+/**
+ * Tests restarting ISR using function wiringPiISR2().
+ */
+class ISRRestart2 : public ::testing::Test {
+ public:
+  static void SetUpTestSuite() {
+    wiringPiSetup();
+    pinMode(TRIGGER_PIN, OUTPUT);
+    digitalWrite(TRIGGER_PIN, LOW);
+    counters_a.primary = &count;
+    counters_a.secondary = &count2;
+    counters_b.primary = &count;
+    counters_b.secondary = &count3;
+    wiringPiISR2(LISTENER_PIN, INT_EDGE_RISING, ISRRestart2::TriggerCount, 1000,
+                 &counters_a);
+    delay(100);
+  }
+
+  static int32_t count;
+  static int32_t count2;
+  static int32_t count3;
+
+  static counters counters_a;
+  static counters counters_b;
+
+  static void TriggerCount(WPIWfiStatus, void *userdata) {
+    struct counters *counters = (struct counters *)userdata;
+    ++*counters->primary;
+    ++*counters->secondary;
+  }
+
+  static void TriggerCountDown(WPIWfiStatus, void *userdata) {
+    struct counters *counters = (struct counters *)userdata;
+    ++*counters->primary;
+    --*counters->secondary;
+  }
+
+ protected:
+  virtual void SetUp() {
+    count = 0;
+    count2 = 0;
+    count3 = 0;
+  }
+
+  virtual void TearDown() {
+    digitalWrite(TRIGGER_PIN, LOW);
+    delay(10);
+  }
+};
+
+int32_t ISRRestart2::count = 0;
+int32_t ISRRestart2::count2 = 0;
+int32_t ISRRestart2::count3 = 0;
+struct counters ISRRestart2::counters_a;
+struct counters ISRRestart2::counters_b;
+
+TEST_F(ISRRestart2, RestartISR2) {
+  // fundamental ISR2 test
+  EXPECT_EQ(count, 0);
+  EXPECT_EQ(count2, 0);
+  digitalWrite(TRIGGER_PIN, HIGH);
+  delay(20);
+  EXPECT_EQ(count, 1);
+  EXPECT_EQ(count2, 1);
+  digitalWrite(TRIGGER_PIN, LOW);
+  delay(20);
+  EXPECT_EQ(count, 1);
+  EXPECT_EQ(count2, 1);
+
+  // stop the ISR
+  EXPECT_EQ(wiringPiISRStop(LISTENER_PIN), 0);
+  delay(100);
+  digitalWrite(TRIGGER_PIN, HIGH);
+  delay(20);
+  EXPECT_EQ(count, 1);
+  EXPECT_EQ(count2, 1);
+  EXPECT_EQ(count3, 0);
+  digitalWrite(TRIGGER_PIN, LOW);
+
+  // start another ISR2 on the same pin
+  EXPECT_EQ(wiringPiISR2(LISTENER_PIN, INT_EDGE_FALLING,
+                         ISRRestart2::TriggerCountDown, 0, &counters_b),
+            0);
+  delay(100);
+  digitalWrite(TRIGGER_PIN, HIGH);
+  delay(20);
+  EXPECT_EQ(count, 1);
+  EXPECT_EQ(count2, 1);
+  EXPECT_EQ(count3, 0);
+
+  digitalWrite(TRIGGER_PIN, LOW);
+  delay(20);
+  EXPECT_EQ(count, 2);
+  EXPECT_EQ(count2, 1);
+  EXPECT_EQ(count3, -1);
+}
diff --git a/wiringPi/gtest/test_isr_rising.cpp b/wiringPi/gtest/test_isr_rising.cpp
new file mode 100644
index 0000000..ea5473c
--- /dev/null
+++ b/wiringPi/gtest/test_isr_rising.cpp
@@ -0,0 +1,80 @@
+#include <gtest/gtest.h>
+#include <time.h>
+#include <wiringPi.h>
+
+#define TRIGGER_PIN  0  // BCM 17
+#define LISTENER_PIN 1  // BCM 18
+#define ANOTHER_LISTENER_PIN 26  // BCM 12
+
+/**
+ * Tests ISR for rising edges.
+ */
+class ISRRising : public ::testing::Test {
+ public:
+  static void SetUpTestSuite() {
+    wiringPiSetup();
+    pinMode(TRIGGER_PIN, OUTPUT);
+    digitalWrite(TRIGGER_PIN, LOW);
+    wiringPiISR(LISTENER_PIN, INT_EDGE_RISING, ISRRising::TriggerCount);
+    delay(100);
+  }
+
+  static uint32_t count;
+
+  static void TriggerCount() { ++count; }
+
+  static void TriggerCountDown() { --count; }
+
+ protected:
+  virtual void SetUp() { count = 0; }
+
+  virtual void TearDown() {
+    digitalWrite(TRIGGER_PIN, LOW);
+    delay(10);
+  }
+};
+
+uint32_t ISRRising::count = 0;
+
+TEST_F(ISRRising, Fundamental) {
+  EXPECT_EQ(count, 0u);
+  digitalWrite(TRIGGER_PIN, HIGH);
+  delay(10);
+  EXPECT_EQ(count, 1u);
+  digitalWrite(TRIGGER_PIN, LOW);
+  delay(10);
+  EXPECT_EQ(count, 1u);
+}
+
+TEST_F(ISRRising, ThreeTriggers) {
+  digitalWrite(TRIGGER_PIN, HIGH);
+  delay(10);
+  count = 0;
+  for (int i = 0; i < 6; ++i) {
+    delay(10);
+    digitalWrite(TRIGGER_PIN, i % 2);
+  }
+  delay(10);
+  EXPECT_EQ(count, 3u);
+}
+
+TEST_F(ISRRising, ISRInitConflict) {
+  // this initialization should fail for ISR conflict
+  EXPECT_EQ(
+      wiringPiISR(LISTENER_PIN, INT_EDGE_FALLING, ISRRising::TriggerCountDown),
+      -1);
+  // ensure the initialization above has released the mutex lock
+  EXPECT_EQ(wiringPiISR(ANOTHER_LISTENER_PIN, INT_EDGE_RISING,
+                        ISRRising::TriggerCountDown),
+            0);
+  delay(100);
+
+  // ensure the existing ISR has not broken
+  EXPECT_EQ(count, 0u);
+  digitalWrite(TRIGGER_PIN, HIGH);
+  delay(10);
+  EXPECT_EQ(count, 1u);
+  digitalWrite(TRIGGER_PIN, LOW);
+  delay(10);
+  EXPECT_EQ(count, 1u);
+}
diff --git a/wiringPi/gtest/test_isr_rising2.cpp b/wiringPi/gtest/test_isr_rising2.cpp
new file mode 100644
index 0000000..d23b5dd
--- /dev/null
+++ b/wiringPi/gtest/test_isr_rising2.cpp
@@ -0,0 +1,136 @@
+#include <gtest/gtest.h>
+#include <time.h>
+#include <wiringPi.h>
+
+#define TRIGGER_PIN  0  // BCM 17
+#define LISTENER_PIN 1  // BCM 18
+#define ANOTHER_LISTENER_PIN 6  // BCM 25
+
+struct counters {
+  uint32_t *primary;
+  uint32_t *secondary;
+};
+
+/**
+ * Tests ISR for rising edges.
+ * Function wiringPiISR2 is used for the configuraiton.
+ */
+class ISRRising2 : public ::testing::Test {
+ public:
+  static void SetUpTestSuite() {
+    wiringPiSetup();
+    pinMode(TRIGGER_PIN, OUTPUT);
+    digitalWrite(TRIGGER_PIN, LOW);
+    counters_a.primary = &count;
+    counters_a.secondary = &count2;
+    counters_b.primary = &count;
+    counters_b.secondary = &count3;
+    wiringPiISR2(LISTENER_PIN, INT_EDGE_RISING, ISRRising2::TriggerCount, 1000,
+                 &counters_a);
+    delay(100);
+  }
+
+  static uint32_t count;
+  static uint32_t count2;
+  static uint32_t count3;
+
+  static counters counters_a;
+  static counters counters_b;
+
+  static void TriggerCount(WPIWfiStatus, void *userdata) {
+    struct counters *counters = (struct counters *)userdata;
+    ++*counters->primary;
+    ++*counters->secondary;
+  }
+
+  static void TriggerCountDown(WPIWfiStatus, void *userdata) {
+    struct counters *counters = (struct counters *)userdata;
+    ++*counters->primary;
+    --*counters->secondary;
+  }
+
+ protected:
+  virtual void SetUp() {
+    count = 0;
+    count2 = 0;
+    count3 = 0;
+  }
+
+  virtual void TearDown() {
+    digitalWrite(TRIGGER_PIN, LOW);
+    delay(10);
+  }
+};
+
+uint32_t ISRRising2::count = 0;
+uint32_t ISRRising2::count2 = 0;
+uint32_t ISRRising2::count3 = 0;
+struct counters ISRRising2::counters_a;
+struct counters ISRRising2::counters_b;
+
+TEST_F(ISRRising2, Fundamental) {
+  EXPECT_EQ(count, 0u);
+  EXPECT_EQ(count2, 0u);
+  digitalWrite(TRIGGER_PIN, HIGH);
+  delay(20);
+  EXPECT_EQ(count, 1u);
+  EXPECT_EQ(count2, 1u);
+  digitalWrite(TRIGGER_PIN, LOW);
+  delay(20);
+  EXPECT_EQ(count, 1u);
+  EXPECT_EQ(count2, 1u);
+}
+
+TEST_F(ISRRising2, ThreeTriggers) {
+  digitalWrite(TRIGGER_PIN, HIGH);
+  delay(10);
+  count = 0;
+  for (int i = 0; i < 6; ++i) {
+    delay(20);
+    digitalWrite(TRIGGER_PIN, i % 2);
+  }
+  delay(20);
+  EXPECT_EQ(count, 3u);
+}
+
+TEST_F(ISRRising2, Debounce) {
+  delay(20);
+  for (int i = 0; i < 7; ++i) {
+    digitalWrite(TRIGGER_PIN, (i + 1) % 2);
+  }
+  delay(20);
+  EXPECT_EQ(count, 1u);
+}
+
+TEST_F(ISRRising2, ISRInitConflict) {
+  // this initialization should fail for ISR conflict
+  EXPECT_EQ(wiringPiISR2(LISTENER_PIN, INT_EDGE_FALLING,
+                         ISRRising2::TriggerCountDown, 0, &counters_b),
+            -1);
+  // ensure the initialization above has released the mutex lock
+  EXPECT_EQ(wiringPiISR2(ANOTHER_LISTENER_PIN, INT_EDGE_BOTH,
+                         ISRRising2::TriggerCountDown, 0, &counters_b),
+            0);
+  delay(100);
+
+  // ensure the existing ISR has not broken
+  EXPECT_EQ(count, 0u);
+  EXPECT_EQ(count2, 0u);
+  digitalWrite(TRIGGER_PIN, HIGH);
+  delay(20);
+  EXPECT_EQ(count, 1u);
+  EXPECT_EQ(count2, 1u);
+  digitalWrite(TRIGGER_PIN, LOW);
+  delay(20);
+  EXPECT_EQ(count, 1u);
+  EXPECT_EQ(count2, 1u);
+
+  delay(20);
+  count = 0;
+  for (int i = 0; i < 7; ++i) {
+    delay(1);
+    digitalWrite(TRIGGER_PIN, (i + 1) % 2);
+  }
+  delay(20);
+  EXPECT_EQ(count, 1u);
+}
diff --git a/wiringPi/test/wiringpi_test7_bench.c b/wiringPi/test/wiringpi_test7_bench.c
index 9c0f221..ffdf367 100644
--- a/wiringPi/test/wiringpi_test7_bench.c
+++ b/wiringPi/test/wiringpi_test7_bench.c
@@ -83,7 +83,8 @@ int main (void) {
     case PI_MODEL_400:
     case PI_MODEL_CM4:
     case PI_MODEL_CM4S:
-      fExpectTimedigitalWrite = 0.020; //us
+      //fExpectTimedigitalWrite = 0.020; //us  - with kernel <6.12.47
+      fExpectTimedigitalWrite = 0.016; //us
       fExpectTimedigitalRead  = 0.038; //us
       fExpectTimepinMode      = 0.121; //us
       fWriteReadDelayFactor   = 1.86;
diff --git a/wiringPi/wiringPi.c b/wiringPi/wiringPi.c
index 4537192..d387d1a 100644
--- a/wiringPi/wiringPi.c
+++ b/wiringPi/wiringPi.c
@@ -1,7 +1,7 @@
 /*
  * wiringPi:
  *	Arduino look-a-like Wiring library for the Raspberry Pi
- *	Copyright (c) 2012-2025 Gordon Henderson and contributors
+ *	Copyright (c) 2012–2019 Gordon Henderson; 2019–2026 Contributors
  *	Additional code for pwmSetClock by Chris Hall <chris@kchall.plus.com>
  *
  *	Thanks to code samples from Gert Jan van Loo and the
@@ -2868,42 +2868,32 @@ int waitForInterruptClose(int pin) {
 }
 
 /*
- * interruptHandlerV2:
- *	This is a thread and gets started to wait for the interrupt we're
- *	hoping to catch. It will call the user-function when the interrupt
- *	fires.
+ * interruptHandlerInit:
+ *	Initializes an interrupt handler before starting the listener loop in a
+ *	separate thread.
+ *	Returns: >0 on successful initialization, 0 if the listener loop does not
+ *	have to start, -1 on error.
  *********************************************************************************
  */
 
-void *interruptHandlerV2(void *arg)
+static int interruptHandlerInit(int pin, int EdgeMode, unsigned long debounce_period_us)
 {
-  const char* strmode = ""; 
-  int pin, EdgeMode, ret, fd, attr, i;
-  unsigned int readret;
-  unsigned long debounce_period_us;
-  struct pollfd polls ;  
+  const char* strmode = "";
+  int ret, attr;
   struct gpio_v2_line_config config;
   struct gpio_v2_line_request req;
-  struct gpio_v2_line_event evdat[64];  
-  struct WPIWfiStatus wfiStatus;
-  struct timespec tspec = {0, 5e5};  /* 0.5 ms timeout {0, 1e6} */
-  
-  pin = *(int *)arg;
 
-  if (wiringPiGpioDeviceGetFd()<0) {
-    return NULL;
+  if (wiringPiGpioDeviceGetFd() < 0) {
+    return -1;
   }
-    
-  EdgeMode = isrEdgeMode[pin];
-  debounce_period_us = isrDebouncePeriodUs[pin];
- 
+
   if (wiringPiDebug) {
     printf ("interruptHandlerV2: GPIO line %d, edge mode %d, debounce_period_us %lu \n", pin, EdgeMode, debounce_period_us) ;
-  } 
-  
+  }
+
   memset(&req, 0, sizeof(req));
   memset(&config, 0, sizeof(config));
-  
+
   /* setup config */
   config.flags = GPIO_V2_LINE_FLAG_INPUT;
   switch(EdgeMode) {
@@ -2912,7 +2902,7 @@ void *interruptHandlerV2(void *arg)
       if (wiringPiDebug) {
         printf ("interruptHandlerV2: waitForInterruptMode edge mode INT_EDGE_SETUP - exiting\n") ;
       }
-      return NULL;
+      return 0;
     case INT_EDGE_FALLING:
       config.flags |= GPIO_V2_LINE_FLAG_EDGE_FALLING;
       strmode = "falling";
@@ -2927,7 +2917,7 @@ void *interruptHandlerV2(void *arg)
       break;
   }
   strcpy(req.consumer, "wiringpi_gpio_irq");
-  
+
   if (debounce_period_us) {
 		attr = config.num_attrs;
 		config.num_attrs++;
@@ -2935,7 +2925,7 @@ void *interruptHandlerV2(void *arg)
 		config.attrs[attr].attr.id = GPIO_V2_LINE_ATTR_ID_DEBOUNCE;
 		config.attrs[attr].attr.debounce_period_us = debounce_period_us;
   }
-  
+
   req.num_lines = 1;
   req.event_buffer_size = 45;
   req.offsets[0] = pin;
@@ -2944,16 +2934,46 @@ void *interruptHandlerV2(void *arg)
   ret = ioctl(chipFd, GPIO_V2_GET_LINE_IOCTL, &req);
   if (ret == -1) {
     ReportDeviceError("interruptHandlerV2: get line event", pin , strmode, ret);
-    return NULL;
+    return -1;
   }
 
-  if (wiringPiDebug) 
-    printf ("interruptHandlerV2: GPIO get line %d , mode %s succeded, fd=%d\n", pin, strmode, req.fd) ;
+  if (wiringPiDebug) {
+    printf ("interruptHandlerV2: GPIO get line %d , mode %s succeded, fd=%d\n", pin, strmode, req.fd);
+  }
+
+  return req.fd;
+}
+
+struct interrupt_handler_params {
+  int pin;
+  int fd;
+};
+
+/*
+ * interruptHandlerV2:
+ *	This is a thread and gets started to wait for the interrupt we're
+ *	hoping to catch. It will call the user-function when the interrupt
+ *	fires.
+ *********************************************************************************
+ */
+
+static void *interruptHandlerV2(void *arg)
+{
+  struct interrupt_handler_params *params;
+  int pin, ret, fd, i;
+  unsigned int readret;
+  struct pollfd polls ;
+  struct gpio_v2_line_event evdat[64];
+  struct WPIWfiStatus wfiStatus;
+  struct timespec tspec = {0, 5e5};  /* 0.5 ms timeout {0, 1e6} */
+
+  params = (struct interrupt_handler_params *)arg;
+  pin = params->pin;
+  fd = params->fd;
 
   /* set event fd  */
-  fd = req.fd;
   isrFds [pin] = fd;
-  
+
   (void)piHiPri (55) ;	// Only effective if we run as root
 
   for (;;) {    // check if event data is available, check if interruptHandlerV2 thread must be canceled
@@ -2962,24 +2982,24 @@ void *interruptHandlerV2(void *arg)
     polls.fd      = fd;
     polls.events  = POLLIN | POLLPRI;
     polls.revents = 0;
-    
+
     // get event data, this is also a cancelation point, when pthread_cancel is called
     ret = ppoll(&polls, 1, &tspec, NULL);     // returns -1 on error, 0 on timeout, >0 number of elements
-  
+
     if (ret < 0) {      // we do not reach this point if canceled, ppoll does not return, is Cancellation Point
-        if (wiringPiDebug)  
+        if (wiringPiDebug)
             printf("interruptHandlerV2: ERROR: poll returned=%d\n", ret);
-        pthread_exit(NULL); 
+        pthread_exit(NULL);
         return NULL;        // never landing here
-    } else if (ret == 0) { 
-//        if (wiringPiDebug)  
+    } else if (ret == 0) {
+//        if (wiringPiDebug)
 //            printf("interruptHandlerV2: timeout: poll returned=%d\n", ret);
         continue;
     }
     else {
         if (wiringPiDebug)
             printf ("interruptHandlerV2: IRQ line %d received %d events, fd=%d\n", pin, ret, isrFds[pin]) ;
-        if (polls.revents & POLLIN) {  
+        if (polls.revents & POLLIN) {
             /* read event data */
             readret = read(fd, &evdat, sizeof(evdat));
             if (readret >= sizeof(evdat[0])) {
@@ -2989,7 +3009,7 @@ void *interruptHandlerV2(void *arg)
                 ret = readret/sizeof(evdat[0]);     // number of events read from fd
                 for (i = 0; i < ret; ++i) {
                     if (isrFunctionsV2[pin]) {
-                        if (wiringPiDebug) 
+                        if (wiringPiDebug)
                             printf( "interruptHandlerV2: GPIO EVENT at %llu on line %u (%u|%u) \n", evdat[i].timestamp_ns, evdat[i].offset, evdat[i].line_seqno, evdat[i].seqno);
                         wfiStatus.statusOK = 1;
                         wfiStatus.pinBCM = pin;
@@ -3006,10 +3026,10 @@ void *interruptHandlerV2(void *arg)
                                 break;
                             default:
                                 wfiStatus.edge = INT_EDGE_SETUP;        // edge = 0
-                                if (wiringPiDebug) 
+                                if (wiringPiDebug)
                                     printf("waitForInterrupt2: unknown event\n");
                                 break;
-                        }        
+                        }
                         wfiStatus.timeStamp_us = evdat[i].timestamp_ns/1000LL;
                         if (wiringPiDebug) {
                           printf( "interruptHandlerV2: call isr function\n");
@@ -3033,7 +3053,7 @@ void *interruptHandlerV2(void *arg)
             else {  // if thread canceled we do not reach this point, read(...) does not return, is Cancellation Point
                 if (wiringPiDebug)
                     printf ("interruptHandlerV2: reading events from fd received signal, exit thread\n");
-                pthread_exit(NULL);  
+                pthread_exit(NULL);
                 return NULL; // never landing here
             }
         }
@@ -3041,9 +3061,8 @@ void *interruptHandlerV2(void *arg)
   }
 }
 
-
 /*
- * wiringPiISR:
+ * wiringPiISRInternal:
  *	Pi Specific.
  *	Take the details and create an interrupt handler that will do a call-
  *	back to the user supplied function.
@@ -3064,38 +3083,48 @@ int wiringPiISRInternal(int pin, int edgeMode, void (*function)(struct WPIWfiSta
     printf("wiringPi: wiringPiISR pin %d, edgeMode %d\n", pin, edgeMode);
   }
   if (isrFunctions[pin] || isrFunctionsV2[pin]) {
-    fprintf(stderr, "wiringPi: ISR function already active, ignoring \n");
+    fprintf(stderr, "wiringPi: ISR function already active\n");
   }
 
-  isrFunctionsV2[pin] = function;
-  isrUserdata[pin] = userdata;
-  isrFunctions[pin] = functionClassic;
-  isrEdgeMode[pin] = edgeMode;
-  isrDebouncePeriodUs[pin] = debounce_period_us;
-  
   if (wiringPiDebug) {
     printf("wiringPi: mutex in\n");
   }
   pthread_mutex_lock (&pinMutex) ;
-    pinPass = pin ;
-    if (wiringPiDebug) {
-      printf("wiringPi: pthread_create before 0x%lX\n", (unsigned long)isrThreads[pin]);
+    struct interrupt_handler_params params = {
+      .pin = pin,
+    };
+    params.fd = interruptHandlerInit(pin, edgeMode, debounce_period_us);
+    if (params.fd < 0) {
+      pthread_mutex_unlock (&pinMutex) ;
+      return -1;
     }
-    if (pthread_create (&isrThreads[pin], NULL, interruptHandlerV2, &pin)==0) {
+
+    // OK to start the new ISR. Update the table.
+    isrFunctionsV2[pin] = function;
+    isrUserdata[pin] = userdata;
+    isrFunctions[pin] = functionClassic;
+    isrEdgeMode[pin] = edgeMode;
+    isrDebouncePeriodUs[pin] = debounce_period_us;
+
+    pinPass = pin ;
+    if (params.fd > 0) {
       if (wiringPiDebug) {
-        printf("wiringPi: pthread_create successed, 0x%lX\n", (unsigned long)isrThreads[pin]);
+        printf("wiringPi: pthread_create before 0x%lX\n", (unsigned long)isrThreads[pin]);
       }
-/*      while (pinPass != -1)
-        delay (1) ; */
-    // wait so that interruptHandler is up und running. 
-    // when interruptHandler is running, the calling function wiringPiISR
-    // must be still alive, otherwise the thread argument &pin points into nirwana,
-    // when it is picked up from interruptHandler.
-      delay (10);
-    } else {
-      if (wiringPiDebug) {
-        printf("wiringPi: pthread_create failed\n");
+      if (pthread_create (&isrThreads[pin], NULL, interruptHandlerV2, &params)==0) {
+        if (wiringPiDebug) {
+          printf("wiringPi: pthread_create successed, 0x%lX\n", (unsigned long)isrThreads[pin]);
+        }
+      } else {
+        if (wiringPiDebug) {
+          printf("wiringPi: pthread_create failed\n");
+        }
       }
+      // wait so that interruptHandler is up und running.
+      // when interruptHandler is running, the calling function wiringPiISRInternal
+      // must be still alive, otherwise the thread argument &param points into nirwana,
+      // when it is picked up from interruptHandlerV2.
+      delay(10);
     }
 
     if (wiringPiDebug) {
diff --git a/wiringPi/wiringPi.h b/wiringPi/wiringPi.h
index 819a58f..07cd258 100644
--- a/wiringPi/wiringPi.h
+++ b/wiringPi/wiringPi.h
@@ -1,7 +1,7 @@
 /*
  * wiringPi.h:
  *	Arduino like Wiring library for the Raspberry Pi.
- *	Copyright (c) 2012-2025 Gordon Henderson
+ *	Copyright (c) 2012–2019 Gordon Henderson; 2019–2026 Contributors
  ***********************************************************************
  * This file is part of wiringPi:
  *	https://github.com/WiringPi/WiringPi/
diff --git a/wiringPi/wiringPiI2C.c b/wiringPi/wiringPiI2C.c
index 95131c3..6ec1789 100644
--- a/wiringPi/wiringPiI2C.c
+++ b/wiringPi/wiringPiI2C.c
@@ -1,7 +1,7 @@
 /*
  * wiringPiI2C.c:
  *	Simplified I2C access routines
- *	Copyright (c) 2013-2024 Gordon Henderson and contributors
+ *	Copyright (c) 2013–2019 Gordon Henderson; 2019–2026 Contributors
  ***********************************************************************
  * This file is part of wiringPi:
  *	https://github.com/WiringPi/WiringPi/
diff --git a/wiringPi/wiringPiI2C.h b/wiringPi/wiringPiI2C.h
index 112257a..22df490 100644
--- a/wiringPi/wiringPiI2C.h
+++ b/wiringPi/wiringPiI2C.h
@@ -1,7 +1,7 @@
 /*
  * wiringPiI2C.h:
  *	Simplified I2C access routines
- *	Copyright (c) 2013-2024 Gordon Henderson and contributors
+ *	Copyright (c) 2013–2019 Gordon Henderson; 2019–2026 Contributors
  ***********************************************************************
  * This file is part of wiringPi:
  *	https://github.com/WiringPi/WiringPi/
diff --git a/wiringPi/wiringPiSPI.c b/wiringPi/wiringPiSPI.c
index 581a079..840f175 100644
--- a/wiringPi/wiringPiSPI.c
+++ b/wiringPi/wiringPiSPI.c
@@ -1,7 +1,7 @@
 /*
  * wiringPiSPI.c:
  *	Simplified SPI access routines
- *	Copyright (c) 2012-2025 Gordon Henderson and contributors
+ *	Copyright (c) 2012–2019 Gordon Henderson; 2019–2026 Contributors
  ***********************************************************************
  * This file is part of wiringPi:
  *	https://github.com/WiringPi/WiringPi/
@@ -44,9 +44,11 @@
 //static const char       *spiDev1  = "/dev/spidev0.1" ;
 static const uint8_t     spiBPW   = 8 ;
 static const uint16_t    spiDelay = 0 ;
-//https://datasheets.raspberrypi.com/cm4/cm4-datasheet.pdf
+//https://datasheets.raspberrypi.com/cm4/cm4-datasheet.pdf   SPI0-6, CS0-2
+//cm5-datasheet.pdf                                          SPI0-5, CS depend on SPInumber, can be up to 4
+//spi0-4cs.dts                                               extention for supporting CS0-4
 const uint8_t     WPI_MaxSPINumbers   = 7 ;
-const uint8_t     WPI_MaxSPIChannels  = 3 ;
+const uint8_t     WPI_MaxSPIChannels  = 5 ;
 
 
 static uint32_t    spiSpeeds [7][3] =
diff --git a/wiringPi/wiringPiSPI.h b/wiringPi/wiringPiSPI.h
index d60b064..aa15aa6 100644
--- a/wiringPi/wiringPiSPI.h
+++ b/wiringPi/wiringPiSPI.h
@@ -1,7 +1,7 @@
 /*
  * wiringPiSPI.h:
  *	Simplified SPI access routines
- *	Copyright (c) 2012-2025 Gordon Henderson and contributors
+ *	Copyright (c) 2012–2019 Gordon Henderson; 2019–2026 Contributors
  ***********************************************************************
  * This file is part of wiringPi:
  *	https://github.com/WiringPi/WiringPi/