revise MRAA driver's GPIO implementation

RF24.cpp

@@ -1030,11 +1030,6 @@ bool RF24::_init_pins()
 
 #if defined(RF24_LINUX)
 
- #if defined(MRAA)
- GPIO();
- gpio.begin(ce_pin, csn_pin);
- #endif
-
  pinMode(ce_pin, OUTPUT);
  ce(LOW);
  delay(100);

RF24.h

@@ -127,9 +127,6 @@ class RF24
 #if defined(RF24_SPI_PTR)
  _SPI* _spi;
 #endif // defined (RF24_SPI_PTR)
-#if defined(MRAA)
- GPIO gpio;
-#endif
 
  rf24_gpio_pin_t ce_pin; /* "Chip Enable" pin, activates the RX or TX role */
  rf24_gpio_pin_t csn_pin; /* SPI Chip select */

utility/MRAA/RF24_arch_config.h

@@ -22,8 +22,6 @@
 
 #define RF24_LINUX
 //typedef uint16_t prog_uint16_t;
-typedef uint16_t rf24_gpio_pin_t;
-#define RF24_PIN_INVALID 0xFFFF
 
 #define PSTR(x) (x)
 #define printf_P printf
@@ -38,9 +36,9 @@ typedef uint16_t rf24_gpio_pin_t;
  #define IF_SERIAL_DEBUG(x)
 #endif
 
-#define digitalWrite(pin, value) gpio.write(pin, value)
+#define digitalWrite(pin, value) GPIO::write(pin, value)
 #define digitalRead(pin) GPIO::read(pin)
-#define pinMode(pin, direction) gpio.open(pin, direction)
+#define pinMode(pin, direction) GPIO::open(pin, direction)
 
 #ifndef __TIME_H__
  // Prophet: Redefine time functions only if precompiled arduino time is not included

utility/MRAA/gpio.cpp

@@ -3,92 +3,74 @@
  *
  */
 
+#include <map>
 #include "gpio.h"
 
+// cache for mraa::Gpio instances
+std::map<rf24_gpio_pin_t, mraa::Gpio*> gpio_cache;
+
 GPIO::GPIO()
 {
- // Prophet: basic members initialization
- gpio_ce_pin = -1;
- //gpio_cs_pin = -1;
- gpio_0 = NULL;
- //gpio_1 = NULL;
 }
 
 GPIO::~GPIO()
 {
- // Prophet: this should free memory, and unexport pins when RF24 and/or GPIO gets deleted or goes out of scope
- this->close(gpio_ce_pin);
- //this->close(gpio_cs_pin);
-}
-
-void GPIO::begin(uint8_t ce_pin, uint8_t cs_pin)
-{
- gpio_ce_pin = ce_pin;
- //gpio_cs_pin = cs_pin;
-
- // Prophet: owner can be set here, because we use our pins exclusively, and are making mraa:Gpio context persistent
- // so pins will be unexported only if close is called, or on destruction
- gpio_0 = new mraa::Gpio(ce_pin /*,0*/);
- //gpio_1 = new mraa::Gpio(cs_pin/*,0*/);
+ // deinitialize cache of mraa::Gpio instances/pointers
+ std::map<rf24_gpio_pin_t, mraa::Gpio*>::iterator i;
+ for (i = gpio_cache.begin(); i != gpio_cache.end(); i++) {
+ i->second->close();
+ }
+ gpio_cache.clear();
 }
 
-void GPIO::open(int port, int DDR)
+void GPIO::open(rf24_gpio_pin_t port, mraa::Dir DDR)
 {
- if (port == gpio_ce_pin) {
- gpio_0 = new mraa::Gpio(port, 0);
- // WARNING: use of memory mapped file system is deprecated in MRAA lib
- gpio_0->useMmap(true); // `false` (or just not calling `useMmap()`) uses default file system?
- gpio_0->dir((mraa::Dir)DDR);
+ // check that mraa::Gpio context doesn't already exist
+ std::map<rf24_gpio_pin_t, mraa::Gpio*>::iterator i = gpio_cache.find(port);
+ if (i == gpio_cache.end()) {
+ mraa::Gpio* gpio_inst = new mraa::Gpio(port);
+ gpio_cache[port] = gpio_inst;
+ gpio_inst->dir(DDR);
+ }
+ else {
+ i->second->dir(DDR);
  }
- /*
- else if(port == gpio_cs_pin) {
- gpio_1 = new mraa::Gpio(port,0);
- gpio_1->useMmap(true);
- gpio_1->dir( (mraa::Dir)DDR);
- }*/
 }
 
-void GPIO::close(int port)
+void GPIO::close(rf24_gpio_pin_t port)
 {
- // Prophet: using same theme of working with port numbers as with GPIO::open,
- // checking for mraa::Gpio context existence to be sure, that GPIO::begin was called
- if (port == gpio_ce_pin) {
- if (gpio_0 != NULL) {
- delete gpio_0;
- }
+ // check that mraa::Gpio context exists, meaning GPIO::open() was called.
+ std::map<rf24_gpio_pin_t, mraa::Gpio*>::iterator i = gpio_cache.find(port);
+ if (i != gpio_cache.end()) {
+ i->second->close(); // close the cached Gpio instance
+ gpio_cache.erase(i); // Delete cache entry
  }
-
- /*
- if(port == gpio_cs_pin) {
- if (gpio_1 != NULL) {
- delete gpio_1;
- }
- }
- */
 }
 
-int GPIO::read(int port)
+int GPIO::read(rf24_gpio_pin_t port)
 {
- if (port == gpio_ce_pin) {
- return gpio_0->read();
- }
- /*
- else if(port == gpio_cs_pin) {
- return gpio_1->read();
+ // get cache gpio instance
+ std::map<rf24_gpio_pin_t, mraa::Gpio*>::iterator i = gpio_cache.find(port);
+ if (i != gpio_cache.end()) {
+ return i->second->read();
  }
- */
+ throw GPIOException("[GPIO::read] pin was not initialized with GPIO::open()");
  return -1;
 }
 
-void GPIO::write(int port, int value)
+void GPIO::write(rf24_gpio_pin_t port, int value)
 {
-
- if (port == gpio_ce_pin) {
- gpio_0->write(value);
+ mraa::Result result = mraa::Result::ERROR_UNSPECIFIED; // a default
+ // get cache gpio instance
+ std::map<rf24_gpio_pin_t, mraa::Gpio*>::iterator i = gpio_cache.find(port);
+ if (i != gpio_cache.end()) {
+ result = i->second->write(value);
+ }
+ else {
+ throw GPIOException("[GPIO::write] pin was not initialized with GPIO::open()");
  }
- /*
- else if(port == gpio_cs_pin) {
- gpio_1->write( value);
+
+ if (result != mraa::Result::SUCCESS) {
+ throw GPIOException("GPIO::write() failed");
  }
- */
 }

utility/MRAA/gpio.h

@@ -6,8 +6,22 @@
 #ifndef RF24_UTILITY_MRAA_GPIO_H_
 #define RF24_UTILITY_MRAA_GPIO_H_
 
+#include <stdexcept> // std::runtime_error, std::string
 #include "mraa.hpp"
 
+typedef uint16_t rf24_gpio_pin_t;
+#define RF24_PIN_INVALID 0xFFFF
+
+/** Specific exception for GPIO errors */
+class GPIOException : public std::runtime_error
+{
+public:
+ explicit GPIOException(const std::string& msg)
+ : std::runtime_error(msg)
+ {
+ }
+};
+
 class GPIO
 {
 
@@ -16,21 +30,13 @@ class GPIO
 
  virtual ~GPIO();
 
- void begin(uint8_t ce_pin, uint8_t cs_pin);
-
- void open(int port, int DDR);
-
- void close(int port);
+ static void open(rf24_gpio_pin_t port, mraa::Dir DDR);
 
- int read(int port);
+ static void close(rf24_gpio_pin_t port);
 
- void write(int port, int value);
+ static int read(rf24_gpio_pin_t port);
 
-private:
- int gpio_ce_pin; /** ce_pin value of the RF24 device **/
- // int gpio_cs_pin; /** cs_pin value of the RF24 device **/
- mraa::Gpio* gpio_0; /** gpio object for ce_pin **/
- // mraa::Gpio* gpio_1; /** gpio object for cs_pin **/
+ static void write(rf24_gpio_pin_t port, int value);
 };
 
 #endif // RF24_UTILITY_MRAA_GPIO_H_