Use const void* for ownership token

Author: henrygab

cores/nRF5/HardwarePWM.cpp

@@ -54,21 +54,21 @@ HardwarePWM* HwPWMx[] =
 };
 
 // returns true ONLY when (1) no PWM channel has a pin, and (2) the owner token is nullptr
-bool HardwarePWM::takeOwnership(uintptr_t token)
+bool HardwarePWM::takeOwnership(void const * token)
 {
   if (this->_owner_token       != 0) return false; // doesn't matter if it's actually a match ... it's not legal to take ownership twice
   if (this->usedChannelCount() != 0) return false; // at least one channel is already in use
-  if (this->enabled                ) return false; // if it's enabled, do not allow new ownership, even with no pins in use
+  if (this->enabled()              ) return false; // if it's enabled, do not allow new ownership, even with no pins in use
   // use gcc built-in intrinsic to ensure atomicity
   // See https://gcc.gnu.org/onlinedocs/gcc/_005f_005fsync-Builtins.html
   return __sync_bool_compare_and_swap(&(this->_owner_token), 0, token);
 }
 // returns true ONLY when (1) no PWM channel has a pin attached, and (2) the owner token matches
-bool HardwarePWM::releaseOwnership(uintptr_t token)
+bool HardwarePWM::releaseOwnership(void const * token)
 {
   if (!this->isOwner(token)         ) return false; // don't even look at peripheral
   if ( this->usedChannelCount() != 0) return false; // fail if any channels still have pins
-  if ( this->enabled                ) return false; // if it's enabled, do not allow ownership to be released, even with no pins in use
+  if ( this->enabled()              ) return false; // if it's enabled, do not allow ownership to be released, even with no pins in use
   // use gcc built-in intrinsic to ensure atomicity
   // See https://gcc.gnu.org/onlinedocs/gcc/_005f_005fsync-Builtins.html
   return __sync_bool_compare_and_swap(&(this->_owner_token), token, 0);

cores/nRF5/HardwarePWM.h

@@ -50,7 +50,7 @@ class HardwarePWM
   private:
     enum { MAX_CHANNELS = 4 }; // Max channel per group
     NRF_PWM_Type* _pwm;
-    uintptr_t _owner_token = 0;
+    void const *  _owner_token = nullptr;
 
     uint16_t _seq0[MAX_CHANNELS];
 
@@ -71,11 +71,12 @@ class HardwarePWM
     // Cooperative ownership sharing
 
     // returns true ONLY when (1) no PWM channel has a pin, and (2) the owner token is nullptr
-    bool takeOwnership(uintptr_t token);
+    bool takeOwnership   (void const * token);
     // returns true ONLY when (1) no PWM channel has a pin attached, and (2) the owner token matches
-    bool releaseOwnership(uintptr_t token);
+    bool releaseOwnership(void const * token);
+
     // allows caller to verify that they own the peripheral
-    __INLINE bool isOwner(uintptr_t token) __attribute__((__always_inline__))
+    __INLINE bool isOwner(void const * token) __attribute__((__always_inline__))
     {
       return this->_owner_token == token;
     }

cores/nRF5/Tone.cpp

@@ -41,7 +41,7 @@ Version Modified By Date     Comments
 unsigned long int count_duration=0;
 volatile bool no_stop = false;
 uint8_t pin_sound=0;
-static uintptr_t _toneToken = (uintptr_t)(&_toneToken);
+static char const * _toneToken = "Tone";
 
 
 void tone(uint8_t pin, unsigned int frequency, unsigned long duration)

cores/nRF5/wiring_analog.cpp

@@ -47,7 +47,7 @@ extern "C"
 {
 
 static uint8_t _lastAnalogWriteResolution;
-static const uintptr_t _token = (uintptr_t)(&_lastAnalogWriteResolution);
+static char const * _analogToken = "analog";
 
 /**
  * This will apply to all PWM Hardware currently used by analogWrite(),
@@ -59,7 +59,7 @@ void analogWriteResolution( uint8_t res )
   _lastAnalogWriteResolution = res;
   for (int i = 0; i<HWPWM_MODULE_NUM; i++)
   {
-    if (!HwPWMx[i]->isOwner(_token)) continue;
+    if (!HwPWMx[i]->isOwner(_analogToken)) continue;
     HwPWMx[i]->setResolution(res);
   }
 }
@@ -80,7 +80,7 @@ void analogWrite( uint32_t pin, uint32_t value )
   // first, handle the case where the pin is already in use by analogWrite()
   for(int i=0; i<HWPWM_MODULE_NUM; i++)
   {
-    if (!HwPWMx[i]->isOwner(_token)) {
+    if (!HwPWMx[i]->isOwner(_analogToken)) {
       LOG_LV3("ANA", "not currently owner of PWM %d", i);
       continue; // skip if not owner of this PWM instance
     }
@@ -98,7 +98,7 @@ void analogWrite( uint32_t pin, uint32_t value )
   // Next, handle the case where can add the pin to a PWM instance already owned by analogWrite()
   for(int i=0; i<HWPWM_MODULE_NUM; i++)
   {
-    if (!HwPWMx[i]->isOwner(_token)) {
+    if (!HwPWMx[i]->isOwner(_analogToken)) {
       LOG_LV3("ANA", "not currently owner of PWM %d", i);
       continue;
     }
@@ -118,7 +118,7 @@ void analogWrite( uint32_t pin, uint32_t value )
   // 2. it currently has no pins in use.
   for(int i=0; i<HWPWM_MODULE_NUM; i++)
   {
-    if (!HwPWMx[i]->takeOwnership(_token)) {
+    if (!HwPWMx[i]->takeOwnership(_analogToken)) {
       LOG_LV3("ANA", "Could not take ownership of PWM %d", i);
       continue;
     }

libraries/Servo/src/nrf52/Servo.cpp

@@ -21,7 +21,7 @@
 #include <Arduino.h>
 #include <Servo.h>
 
-static uintptr_t _servoToken = (uintptr_t)(&_servoToken);
+static char const * _servoToken = "Servo";
 
 static servo_t servos[MAX_SERVOS];              // static array of servo structures
 uint8_t ServoCount = 0;                         // the total number of attached servos