nunchuck: C port; FTI; C++ wraps C

Some API changes were made as well, see docs/apichanges.md.

Signed-off-by: Jon Trulson <jtrulson@ics.com>

docs/apichanges.md

@@ -4,6 +4,14 @@ API Changes                       {#apichanges}
 Here's a list of other API changes made to the library that break source/binary
 compatibility between releases:
 
+ * **nunchuck** This driver no longer supports the init() function.
+   All initialization is now done in the C nunchuck_init() function,
+   or the C++ constructor.  In addition, the *NUNCHUCK_I2C_ADDR*
+   define is no longer exposed, as it is not possible to use any other
+   I2C address than *0x52*.  The readBytes() and writeByte() functions
+   are also no longer exposed, since aside from what the driver does
+   to initialize and read data, there are no other options available.
+
  * **enc03r** This driver no longer supports the value() function.  In
  addition, an update() function has been added.  This function must be
  called prior to calling angularVelocity().  angularVelocity() no

examples/c++/nunchuck.cxx

@@ -43,16 +43,8 @@ int main(int argc, char **argv)
   signal(SIGINT, sig_handler);
 
 //! [Interesting]
-  // Instantiate a nunchuck controller bus 0
-  upm::NUNCHUCK *nunchuck = new upm::NUNCHUCK(0);
-  
-  // always do this first
-  cout << "Initializing... " << endl;
-  if (!nunchuck->init())
-    {
-      cerr << "nunchuck->init() failed." << endl;
-      return 0;
-    }
+  // Instantiate a nunchuck controller bus 3
+  upm::NUNCHUCK *nunchuck = new upm::NUNCHUCK(3);
 
   while (shouldRun)
     {

examples/c/CMakeLists.txt

@@ -148,6 +148,7 @@ add_example (cjq4435)
 add_example (hmc5883l)
 add_example (wfs)
 add_example (enc03r)
+add_example (nunchuck)
 
 # Custom examples
 add_custom_example (nmea_gps_i2c-example-c nmea_gps_i2c.c nmea_gps)

examples/c/nunchuck.c

@@ -0,0 +1,84 @@
+/*
+ * Author: Jon Trulson <jtrulson@ics.com>
+ * Copyright (c) 2015 Intel Corporation.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#include <unistd.h>
+#include <stdio.h>
+#include <signal.h>
+
+#include <upm_utilities.h>
+#include "nunchuck.h"
+
+bool shouldRun = true;
+
+void sig_handler(int signo)
+{
+    if (signo == SIGINT)
+        shouldRun = false;
+}
+
+int main(int argc, char **argv)
+{
+    signal(SIGINT, sig_handler);
+
+//! [Interesting]
+    // Instantiate a nunchuck controller bus 3
+    nunchuck_context sensor = nunchuck_init(3);
+
+    if (!sensor)
+    {
+        printf("%s: nunchuck_init() failed\n", __FUNCTION__);
+        return 1;
+    }
+
+    while (shouldRun)
+    {
+        if (nunchuck_update(sensor))
+        {
+            printf("%s: nunchuck_update() failed\n", __FUNCTION__);
+            nunchuck_close(sensor);
+            return 1;
+        }
+
+        int x, y, z;
+        nunchuck_get_stick(sensor, &x, &y);
+        printf("stickX: %d stickY: %d\n", x, y);
+
+        nunchuck_get_acceleration(sensor, &x, &y, &z);
+        printf("accelX: %d accelY: %d accelZ: %d\n", x, y, z);
+
+        bool bc, bz;
+        nunchuck_get_buttons(sensor, &bc, &bz);
+        printf("button C: %s\n",
+               ((bc) ? "pressed" : "not pressed"));
+        printf("button Z: %s\n\n",
+               ((bz) ? "pressed" : "not pressed"));
+
+        upm_delay_ms(100);
+    }
+
+    nunchuck_close(sensor);
+
+    //! [Interesting]
+    return 0;
+}

examples/java/NUNCHUCKSample.java

@@ -27,21 +27,21 @@ public class NUNCHUCKSample {
     public static void main(String[] args) throws InterruptedException {
         // ! [Interesting]
         // Instantiate a nunchuck controller bus 0
-		upm_nunchuck.NUNCHUCK nunchuck = new upm_nunchuck.NUNCHUCK(0);
+        upm_nunchuck.NUNCHUCK nunchuck = new upm_nunchuck.NUNCHUCK(3);
 
-		// always do this first
-		System.out.println("Initializing... ");
-		if (!nunchuck.init()) {
-			System.err.println("nunchuck->init() failed.");
-			return;
-		}
-
-		while (true) {
+        while (true)
+        {
             nunchuck.update();
-			System.out.println("stickX: " + nunchuck.getStickX() + ", stickY: "
+            System.out.println("stickX: "
+                               + nunchuck.getStickX()
+                               + ", stickY: "
                                + nunchuck.getStickY());
-			System.out.println("accelX: " + nunchuck.getAccelX() + ", accelY: "
-					+ nunchuck.getAccelY() + ", accelZ: " + nunchuck.getAccelZ());
+            System.out.println("accelX: "
+                               + nunchuck.getAccelX()
+                               + ", accelY: "
+                               + nunchuck.getAccelY()
+                               + ", accelZ: "
+                               + nunchuck.getAccelZ());
 
             if (nunchuck.getButtonC())
                 System.out.println("Button C pressed");
@@ -53,7 +53,7 @@ public class NUNCHUCKSample {
             else
                 System.out.println("Button Z not pressed");
 
-			Thread.sleep(1000);
+            Thread.sleep(100);
         }
         // ! [Interesting]
     }

examples/javascript/nunchuck.js

@@ -24,16 +24,8 @@
 
 var nunchuck_lib = require('jsupm_nunchuck');
 
-// Instantiate a nunchuck controller bus 0
-var nunchuck_obj = new nunchuck_lib.NUNCHUCK(0);
-
-// always do this first
-console.log("Initializing... ");
-if (!nunchuck_obj.init())
-{
-	console.log("nunchuck->init() failed.");
-	process.exit(0);
-}
+// Instantiate a nunchuck controller bus 3
+var nunchuck_obj = new nunchuck_lib.NUNCHUCK(3);
 
 setInterval(function()
 {

examples/python/nunchuck.py

@@ -26,8 +26,8 @@ import time, sys, signal, atexit
 from upm import pyupm_nunchuck as upmNunchuck
 
 def main():
-    # Instantiate a nunchuck controller bus 0 on I2C
-    myNunchuck = upmNunchuck.NUNCHUCK(0)
+    # Instantiate a nunchuck controller bus 3 on I2C
+    myNunchuck = upmNunchuck.NUNCHUCK(3)
 
     ## Exit handlers ##
     # This function stops python from printing a stacktrace when you hit control-C
@@ -43,12 +43,6 @@ def main():
     atexit.register(exitHandler)
     signal.signal(signal.SIGINT, SIGINTHandler)
 
-    # always do this first
-    print("Initializing... ")
-    if (not myNunchuck.init()):
-        print("nunchuck->init() failed.")
-        sys.exit(0);
-
     def buttonStateStr(buttonState):
         return "pressed" if buttonState else "not pressed"
 

include/fti/upm_buttons.h

@@ -0,0 +1,46 @@
+/*
+ * Author: Jon Trulson <jtrulson@ics.com>
+ * Copyright (c) 2017 Intel Corporation.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+#ifndef UPM_BUTTONS_H_
+#define UPM_BUTTONS_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+// Buttons function table
+typedef struct _upm_buttons_ft {
+    // This function is used to query button state.  The num_button
+    // specifies the total number of buttons present, and the values
+    // indicates each button's current value as an array of bools.
+    upm_result_t (*upm_buttons_get_num_buttons) (const void *dev,
+                                                 unsigned int *num_buttons);
+    upm_result_t (*upm_buttons_get_values) (const void *dev,
+                                            bool *values);
+} upm_buttons_ft;
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* UPM_BUTTONS_H_ */

include/upm_fti.h

@@ -75,7 +75,8 @@ typedef enum {
     UPM_STREAM,
     UPM_ORP,
     UPM_BINARY,
-    UPM_ROTARYENCODER
+    UPM_ROTARYENCODER,
+    UPM_BUTTONS
 } upm_sensor_t;
 
 /* Supported IO protocols via MRAA */
@@ -127,6 +128,8 @@ typedef struct _upm_sensor_ft* (*func_get_upm_sensor_ft)(upm_sensor_t sensor_typ
 #include <fti/upm_pressure.h>
 #include <fti/upm_compass.h>
 #include <fti/upm_gyroscope.h>
+#include <fti/upm_buttons.h>
+#include <fti/upm_joystick.h>
 
 #ifdef __cplusplus
 }

src/nunchuck/CMakeLists.txt

@@ -1,5 +1,9 @@
-set (libname "nunchuck")
-set (libdescription "Wii nunchuck module")
-set (module_src ${libname}.cxx)
-set (module_hpp ${libname}.hpp)
-upm_module_init()
+upm_mixed_module_init (NAME nunchuck
+    DESCRIPTION "I2C nunchuck driver"
+    C_HDR nunchuck.h
+    C_SRC nunchuck.c
+    CPP_HDR nunchuck.hpp
+    CPP_SRC nunchuck.cxx
+    FTI_SRC nunchuck_fti.c
+    CPP_WRAPS_C
+    REQUIRES mraa)

src/nunchuck/nunchuck.c

@@ -0,0 +1,206 @@
+/*
+ * Author: Jon Trulson <jtrulson@ics.com>
+ * Copyright (c) 2017 Intel Corporation.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <assert.h>
+
+#include "nunchuck.h"
+
+// This is not changeable
+#define NUNCHUCK_I2C_ADDR    0x52
+
+// static functions for r/w the device.  No user-serviceable parts
+// inside.
+
+static upm_result_t nunchuck_write_byte(const nunchuck_context dev,
+                                        uint8_t reg, uint8_t byte)
+{
+    assert(dev != NULL);
+
+    if (mraa_i2c_write_byte_data(dev->i2c, byte, reg))
+    {
+        printf("%s: mraa_i2c_write_byte_data() failed\n", __FUNCTION__);
+        return UPM_ERROR_OPERATION_FAILED;
+    }
+
+    return UPM_SUCCESS;
+}
+
+static int nunchuck_read_bytes(const nunchuck_context dev, uint8_t reg,
+                               uint8_t *buffer, int len)
+{
+    assert(dev != NULL);
+
+    if (!len || !buffer)
+        return 0;
+
+    if (mraa_i2c_write_byte(dev->i2c, reg))
+    {
+        printf("%s: mraa_i2c_write_byte() failed\n", __FUNCTION__);
+        return -1;
+    }
+
+    return mraa_i2c_read(dev->i2c, buffer, len);
+}
+
+// init
+nunchuck_context nunchuck_init(int bus)
+{
+    // make sure MRAA is initialized
+    int mraa_rv;
+    if ((mraa_rv = mraa_init()) != MRAA_SUCCESS)
+    {
+        printf("%s: mraa_init() failed (%d).\n", __FUNCTION__, mraa_rv);
+        return NULL;
+    }
+
+    nunchuck_context dev =
+        (nunchuck_context)malloc(sizeof(struct _nunchuck_context));
+
+    if (!dev)
+        return NULL;
+
+    memset((void *)dev, 0, sizeof(struct _nunchuck_context));
+
+    // setup our i2c link
+    if ( !(dev->i2c = mraa_i2c_init(bus)) )
+    {
+        printf("%s: mraa_i2c_init() failed\n", __FUNCTION__);
+        nunchuck_close(dev);
+        return NULL;
+    }
+
+    if (mraa_i2c_address(dev->i2c, NUNCHUCK_I2C_ADDR))
+    {
+        printf("%s: mraa_i2c_address() failed\n", __FUNCTION__);
+        nunchuck_close(dev);
+        return NULL;
+    }
+
+    // sleep for a second to let things settle
+    upm_delay(1);
+
+    // disable encryption
+    if (nunchuck_write_byte(dev, 0xf0, 0x55)
+        || nunchuck_write_byte(dev, 0xfb, 0x00))
+    {
+        printf("%s: nunchuck_write_byte() failed\n", __FUNCTION__);
+        nunchuck_close(dev);
+        return NULL;
+    }
+
+    return dev;
+}
+
+void nunchuck_close(nunchuck_context dev)
+{
+    assert(dev != NULL);
+
+    if (dev->i2c)
+        mraa_i2c_stop(dev->i2c);
+
+    free(dev);
+}
+
+upm_result_t nunchuck_update(const nunchuck_context dev)
+{
+    assert(dev != NULL);
+
+    const int bufsize = 6;
+    uint8_t buf[bufsize];
+    int rv;
+
+    rv = nunchuck_read_bytes(dev, 0x00, buf, bufsize);
+
+    if (rv != bufsize)
+    {
+        printf("%s: nunchuck_read_bytes() failed.  Expected %d, got %d.\n",
+               __FUNCTION__, bufsize, rv);
+        return UPM_ERROR_OPERATION_FAILED;
+    }
+
+    // analog stick X
+    dev->stickX = buf[0];
+
+    // analog stick Y
+    dev->stickY = buf[1];
+
+    // accelerometer X
+    dev->accelX = ( (buf[2] << 2) | ((buf[5] & 0x0c) >> 2) );
+
+    // accelerometer Y
+    dev->accelY = ( (buf[3] << 2) | ((buf[5] & 0x30) >> 4) );
+
+    // accelerometer Z
+    dev->accelZ = ( (buf[4] << 2) | ((buf[5] & 0xc0) >> 6) );
+
+    // buttonC
+    if (buf[5] & 0x02)
+        dev->buttonC = false;
+    else
+        dev->buttonC = true;
+
+    // buttonZ
+    if (buf[5] & 0x01)
+        dev->buttonZ = false;
+    else
+        dev->buttonZ = true;
+
+    return UPM_SUCCESS;
+}
+
+void nunchuck_get_stick(const nunchuck_context dev, int *x, int *y)
+{
+    assert(dev != NULL);
+
+    if (x)
+        *x = dev->stickX;
+    if (y)
+        *y = dev->stickY;
+}
+
+void nunchuck_get_acceleration(const nunchuck_context dev,
+                               int *x, int *y, int *z)
+{
+    assert(dev != NULL);
+
+    if (x)
+        *x = dev->accelX;
+    if (y)
+        *y = dev->accelY;
+    if (z)
+        *z = dev->accelZ;
+}
+
+void nunchuck_get_buttons(const nunchuck_context dev, bool *c, bool *z)
+{
+    assert(dev != NULL);
+
+    if (c)
+        *c = dev->buttonC;
+    if (z)
+        *z = dev->buttonZ;
+}

src/nunchuck/nunchuck.cxx

@@ -1,6 +1,6 @@
 /*
  * Author: Jon Trulson <jtrulson@ics.com>
- * Copyright (c) 2015 Intel Corporation.
+ * Copyright (c) 2015-2017 Intel Corporation.
  *
  * Permission is hereby granted, free of charge, to any person obtaining
  * a copy of this software and associated documentation files (the
@@ -33,117 +33,27 @@ using namespace upm;
 using namespace std;
 
 
-NUNCHUCK::NUNCHUCK(int bus, uint8_t addr)
+NUNCHUCK::NUNCHUCK(int bus) :
+    m_nunchuck(nunchuck_init(bus))
 {
-  stickX = 0;
-  stickY = 0;
-  accelX = 0;
-  accelY = 0;
-  accelZ = 0;
-  buttonC = false;
-  buttonZ = false;
-
-  // setup our i2c link
-  if ( !(m_i2c = mraa_i2c_init(bus)) ) 
-    {
-      throw std::invalid_argument(std::string(__FUNCTION__) +
-                                  ": mraa_i2c_init() failed");
-      return;
-    }
-
-  mraa_result_t rv;
-
-  if ( (rv = mraa_i2c_address(m_i2c, addr)) != MRAA_SUCCESS )
-    {
-      throw std::invalid_argument(std::string(__FUNCTION__) +
-                                  ": mraa_i2c_address() failed");
-    }
+    if (!m_nunchuck)
+        throw std::runtime_error(string(__FUNCTION__)
+                                 + ": nunchuck_init() failed");
 }
 
 NUNCHUCK::~NUNCHUCK()
 {
-  mraa_i2c_stop(m_i2c);
-}
-
-bool NUNCHUCK::writeByte(uint8_t reg, uint8_t byte)
-{
-  mraa_result_t rv;
-
-  if ( (rv = mraa_i2c_write_byte_data(m_i2c, byte, reg)) != MRAA_SUCCESS )
-    {
-      throw std::runtime_error(std::string(__FUNCTION__) +
-                               ": mraa_i2c_write_byte_data() failed");
-      return false;
-    }
-
-  return true;
-}
-
-int NUNCHUCK::readBytes(uint8_t reg, uint8_t *buffer, int len)
-{
-  if (!len || !buffer)
-    return 0;
-
-  mraa_i2c_address(m_i2c, NUNCHUCK_I2C_ADDR);
-  mraa_i2c_write_byte(m_i2c, reg);
-
-  return mraa_i2c_read(m_i2c, buffer, len);
-}
-
-bool NUNCHUCK::init()
-{
-  usleep(1000000);
-
-  // disable encryption
-  if (!writeByte(0xf0, 0x55))
-    return false;
-
-  if (!writeByte(0xfb, 0x00))
-    return false;
-
-  return true;
+    nunchuck_close(m_nunchuck);
 }
 
 void NUNCHUCK::update()
 {
-  const int bufsize = 6;
-  uint8_t buf[bufsize];
-  int rv;
+    if (nunchuck_update(m_nunchuck))
+        throw std::runtime_error(string(__FUNCTION__)
+                                 + ": nunchuck_update() failed");
 
-  rv = readBytes(0x00, buf, bufsize);
-
-  if (rv != bufsize)
-    {
-      throw std::runtime_error(std::string(__FUNCTION__) +
-                               ": readBytes() failed");
-      return;
-    }
-
-  // analog stick X
-  stickX = buf[0];
-
-  // analog stick Y
-  stickY = buf[1];
-
-  // accelerometer X
-  accelX = ( (buf[2] << 2) | ((buf[5] & 0x0c) >> 2) );
-
-  // accelerometer Y
-  accelY = ( (buf[3] << 2) | ((buf[5] & 0x30) >> 4) );
-
-  // accelerometer Z
-  accelZ = ( (buf[4] << 2) | ((buf[5] & 0xc0) >> 6) );
-
-  // buttonC
-  if (buf[5] & 0x02)
-    buttonC = false;
-  else
-    buttonC = true;
-
-  // buttonZ
-  if (buf[5] & 0x01)
-    buttonZ = false;
-  else
-    buttonZ = true;
+    nunchuck_get_stick(m_nunchuck, &stickX, &stickY);
+    nunchuck_get_acceleration(m_nunchuck, &accelX, &accelY, &accelZ);
+    nunchuck_get_buttons(m_nunchuck, &buttonC, &buttonZ);
 }
 

src/nunchuck/nunchuck.h

@@ -0,0 +1,123 @@
+/*
+ * Author: Jon Trulson <jtrulson@ics.com>
+ * Copyright (c) 2017 Intel Corporation.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+#pragma once
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <upm.h>
+
+#include <mraa/i2c.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+    /**
+     * @file nunchuck.h
+     * @library nunchuck
+     * @brief C API for the nunchuck driver
+     *
+     * @include nunchuck.c
+     */
+
+    /**
+     * Device context
+     */
+    typedef struct _nunchuck_context {
+        mraa_i2c_context  i2c;
+
+        // sticks - x, y
+        int stickX;
+        int stickY;
+
+        // accel
+        int accelX;
+        int accelY;
+        int accelZ;
+
+        // buttons
+        bool buttonC;
+        bool buttonZ;
+
+    } *nunchuck_context;
+
+    /**
+     * NUNCHUCK constructor
+     *
+     * @param bus I2C bus to use
+     * @return A Device context, or NULL on error
+     */
+    nunchuck_context nunchuck_init(int bus);
+
+    /**
+     * Close the device and deallocate all resources.
+     *
+     * @param dev Device context
+     */
+    void nunchuck_close(nunchuck_context dev);
+
+    /**
+     * Reads and updates the current state of the controller.
+     *
+     * @param dev Device context
+     * @return UPM result
+     */
+    upm_result_t nunchuck_update(const nunchuck_context dev);
+
+    /**
+     * Returns the current analog stick X and Y positions.
+     * nunchuck_update() must have been called prior to calling this
+     * function.
+     *
+     * @param dev Device context
+     * @param x Pointer in which the X value will be stored
+     * @param y Pointer in which the Y value will be stored
+     */
+    void nunchuck_get_stick(const nunchuck_context dev, int *x, int *y);
+
+    /**
+     * Returns the current accelerometer values.  nunchuck_update()
+     * must have been called prior to calling this function.
+     *
+     * @param dev Device context
+     * @param x Pointer in which the X value will be stored
+     * @param y Pointer in which the Y value will be stored
+     * @param z Pointer in which the Z value will be stored
+     */
+    void nunchuck_get_acceleration(const nunchuck_context dev,
+                                   int *x, int *y, int *z);
+
+    /**
+     * Returns the current button values values.  nunchuck_update()
+     * must have been called prior to calling this function.
+     *
+     * @param dev Device context
+     * @param c Pointer in which the C button value will be stored
+     * @param z Pointer in which the Z button value will be stored
+     */
+    void nunchuck_get_buttons(const nunchuck_context dev, bool *c, bool *z);
+
+#ifdef __cplusplus
+}
+#endif

src/nunchuck/nunchuck.hpp

@@ -1,6 +1,6 @@
 /*
  * Author: Jon Trulson <jtrulson@ics.com>
- * Copyright (c) 2015 Intel Corporation.
+ * Copyright (c) 2015-2017 Intel Corporation.
  *
  * Permission is hereby granted, free of charge, to any person obtaining
  * a copy of this software and associated documentation files (the
@@ -24,9 +24,8 @@
 #pragma once
 
 #include <string>
-#include <mraa/i2c.h>
+#include "nunchuck.h"
 
-#define NUNCHUCK_I2C_ADDR    0x52
 
 namespace upm {
 
@@ -48,17 +47,16 @@ namespace upm {
    * @brief API for the Wii* Nunchuk controller
    *
    * UPM module for the Wii Nunchuk controller. This module was tested with
-   * Wii Nunchuk connected to I2C via a Grove Wii Nunchuk adapter.
+   * Wii Nunchuck connected to I2C via a Grove Wii Nunchuck adapter.
    *
    * See http://wiibrew.org/wiki/Wiimote/Extension_Controllers and
    * http://wiibrew.org/wiki/Wiimote/Extension_Controllers/Nunchuck
    * for more details on the controller and its protocol.
    *
-   * A warning for the Grove Wii Nunchuk adapter: it has 2 traces on one
-   * side, and 3 traces on the other.  Do not match these up with the
-   * Nunchuk connector's traces. The connector's 'Grove'
-   * should be on the same side as the Grove interface socket on the
-   * adapter.
+   * A warning for the Grove Wii Nunchuk adapter: it has 2 traces on
+   * one side, and 3 traces on the other.  Do not match these up with
+   * the Nunchuk connector's traces. The connector's 'groove' should
+   * be on the same side as the Grove interface socket on the adapter.
    *
    * @image html nunchuck.jpg
    * @snippet nunchuck.cxx Interesting
@@ -71,39 +69,12 @@ namespace upm {
      * @param bus I2C bus to use
      * @param addr I2C address to use
      */
-    NUNCHUCK(int bus, uint8_t addr=NUNCHUCK_I2C_ADDR);
+    NUNCHUCK(int bus);
 
     /**
      * NUNCHUCK destructor
      */
-    ~NUNCHUCK();
-
-    /**
-     * Writes value(s) into registers
-     *
-     * @param reg Register location to start writing into
-     * @param byte Byte to write
-     * @return True if successful
-     */
-    bool writeByte(uint8_t reg, uint8_t byte);
-
-    /**
-     * Reads value(s) from registers
-     *
-     * @param reg Register location to start reading from
-     * @param buffer Buffer for data storage
-     * @param len Number of bytes to read
-     * @return Number of bytes read
-     */
-    int readBytes(uint8_t reg, uint8_t *buffer, int len);
-
-    /**
-     * Initializes the controller. Here, we disable encryption after
-     * delaying for a time to ensure the controller is ready.
-     *
-     * @return True if initialization is successful
-     */
-    bool init();
+    virtual ~NUNCHUCK();
 
     /**
      * Reads and updates the current state of the controller.
@@ -153,8 +124,10 @@ namespace upm {
      */
     bool buttonZ;
 
+  protected:
+      nunchuck_context m_nunchuck;
+
   private:
-    mraa_i2c_context m_i2c;
   };
 }
 

src/nunchuck/nunchuck_fti.c

@@ -0,0 +1,190 @@
+/*
+ * Author: Jon Trulson <jtrulson@ics.com>
+ * Copyright (c) 2017 Intel Corporation.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#include "nunchuck.h"
+
+#include "upm_fti.h"
+
+/**
+ * This file implements the Function Table Interface (FTI) for this sensor
+ */
+
+const char upm_nunchuck_name[] = "NUNCHUCK";
+const char upm_nunchuck_description[] = "Nunchuck controller";
+const upm_protocol_t upm_nunchuck_protocol[] = {UPM_I2C};
+const upm_sensor_t upm_nunchuck_category[] =
+{ UPM_ACCELEROMETER, UPM_JOYSTICK, UPM_BUTTONS};
+
+// forward declarations
+const void* upm_nunchuck_get_ft(upm_sensor_t sensor_type);
+void* upm_nunchuck_init_name();
+void upm_nunchuck_close(void *dev);
+upm_result_t upm_nunchuck_get_accel_values(void *dev, float *value, upm_acceleration_u unit);
+upm_result_t upm_nunchuck_get_joystick_value_x(const void *dev, float *value);
+upm_result_t upm_nunchuck_get_joystick_value_y(const void *dev, float *value);
+upm_result_t upm_nunchuck_get_num_buttons(const void *dev,
+                                          unsigned int *num_buttons);
+upm_result_t upm_nunchuck_get_button_values(const void *dev,
+                                            bool *values);
+
+const upm_sensor_descriptor_t upm_nunchuck_get_descriptor()
+{
+    upm_sensor_descriptor_t usd;
+    usd.name = upm_nunchuck_name;
+    usd.description = upm_nunchuck_description;
+    usd.protocol_size = 1;
+    usd.protocol = upm_nunchuck_protocol;
+    usd.category_size = 3;
+    usd.category = upm_nunchuck_category;
+    return usd;
+}
+
+static const upm_sensor_ft ft =
+{
+    .upm_sensor_init_name = upm_nunchuck_init_name,
+    .upm_sensor_close = upm_nunchuck_close,
+};
+
+static const upm_acceleration_ft aft =
+{
+    .upm_acceleration_get_value = upm_nunchuck_get_accel_values
+};
+
+static const upm_joystick_ft jft =
+{
+    .upm_joystick_get_value_x = upm_nunchuck_get_joystick_value_x,
+    .upm_joystick_get_value_y = upm_nunchuck_get_joystick_value_y
+};
+
+static const upm_buttons_ft bft =
+{
+    .upm_buttons_get_num_buttons = upm_nunchuck_get_num_buttons,
+    .upm_buttons_get_values = upm_nunchuck_get_button_values
+};
+
+const void* upm_nunchuck_get_ft(upm_sensor_t sensor_type)
+{
+  switch(sensor_type)
+    {
+    case UPM_SENSOR:
+      return &ft;
+
+    case UPM_ACCELEROMETER:
+      return &aft;
+
+    case UPM_JOYSTICK:
+      return &jft;
+
+    case UPM_BUTTONS:
+      return &bft;
+
+    default:
+      return NULL;
+    }
+}
+
+void* upm_nunchuck_init_name()
+{
+    return NULL;
+}
+
+void upm_nunchuck_close(void *dev)
+{
+    nunchuck_close((nunchuck_context)dev);
+}
+
+upm_result_t upm_nunchuck_get_accel_values(void *dev,
+                                           float *value,
+                                           upm_acceleration_u unit)
+{
+    if (nunchuck_update((nunchuck_context)dev))
+        return UPM_ERROR_OPERATION_FAILED;
+
+    int x, y, z;
+    nunchuck_get_acceleration((nunchuck_context)dev, &x, &y, &z);
+    value[0] = (float)x;
+    value[1] = (float)y;
+    value[2] = (float)z;
+
+    return UPM_SUCCESS;
+}
+
+upm_result_t upm_nunchuck_get_joystick_value_x(const void *dev, float *value)
+{
+    // This is bad - separating getting X and Y stick values... You
+    // can't be sure when updating for one axis whether the other
+    // changed... Should be fixed by having a single function return
+    // both values from the same sampletime.  Same goes for the rest
+    // of the values reported.
+    if (nunchuck_update((nunchuck_context)dev))
+        return UPM_ERROR_OPERATION_FAILED;
+
+    int x;
+    nunchuck_get_stick((nunchuck_context)dev, &x, NULL);
+    *value = (float)x;
+
+    return UPM_SUCCESS;
+}
+
+upm_result_t upm_nunchuck_get_joystick_value_y(const void *dev, float *value)
+{
+    // This is bad - separating getting X and Y stick values... You
+    // can't be sure when updating for one axis whether the other
+    // changed... Should be fixed by having a single function return
+    // both values from the same sampletime.  Same goes for the rest
+    // of the values reported.
+    if (nunchuck_update((nunchuck_context)dev))
+        return UPM_ERROR_OPERATION_FAILED;
+
+    int y;
+    nunchuck_get_stick((nunchuck_context)dev, NULL, &y);
+    *value = (float)y;
+
+    return UPM_SUCCESS;
+}
+
+upm_result_t upm_nunchuck_get_num_buttons(const void *dev,
+                                          unsigned int *num_buttons)
+{
+    // always 2 buttons (C and Z)
+
+    *num_buttons = 2;
+
+    return UPM_SUCCESS;
+}
+
+upm_result_t upm_nunchuck_get_button_values(const void *dev,
+                                            bool *values)
+{
+    if (nunchuck_update((nunchuck_context)dev))
+        return UPM_ERROR_OPERATION_FAILED;
+
+    bool bc, bz;
+    nunchuck_get_buttons((nunchuck_context)dev, &bc, &bz);
+    // hope they passed a bool[2]....
+    values[0] = bc;
+    values[1] = bz;
+
+    return UPM_SUCCESS;
+}