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>

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;
+}