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>

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_ */