start fleshing things out a very tiny bit

inc/libepd/epd.h

@@ -0,0 +1,19 @@
+/* epd.h - E-Paper Display library API */
+
+#ifndef EPD_H_
+#define EPD_H_
+
+/* Includes */
+#include "stdint.h"
+
+/* Definitions */
+
+/* Data Structures */
+typedef struct epd_s epd_t;
+typedef void (*epd_spi_write)(const uint8_t *, size_t, void *);
+typedef void (*epd_spi_cs)(const uint8_t, void *);
+typedef void (*epd_dc)(const uint8_t, void *);
+
+/* Function Prototypes */
+
+#endif /* EPD_H_ */

inc/libepd/private/priv_epd.h

@@ -0,0 +1,21 @@
+/* priv_epd.h - private definitions for libepd */
+
+#ifndef PRIV_EPD_H_
+#define PRIV_EPD_H_
+
+/* Includes */
+#include "epd.h"
+
+/* Definitions */
+
+/* Data Structures */
+struct epd_s {
+    epd_spi_write spi_write,
+    epd_spi_cs spi_cs,
+    epd_dc dc,
+    void *udata
+};
+
+/* Function Prototypes */
+
+#endif /* PRIV_EPD_H_ */

src/libepd/epd.c

@@ -0,0 +1,15 @@
+/* epd.h - E-Paper Display library API */
+
+/* Includes */
+#include "epd.h"
+#include "priv_epd.h"
+
+/* Definitions */
+
+/* Data Structures */
+
+/* Global Variables */
+
+/* Function Prototypes */
+
+/* Function Definitions */