Add nrf spi driver

include/platform/nrf52/nrf52-dk.h

@@ -4,6 +4,7 @@
 #include "driver.h"
 
 #include "gpio.h"
+#include "spi.h"
 
 // LED 1
 const struct gpio nrf_led_1 = {
@@ -49,4 +50,15 @@ const struct driver led_4 = {
     .dev = &nrf_led_4
 };
 
+const struct spi nrf_spi_0 = {
+    .sck_pin = 2,
+    .mosi_pin = 3,
+    .miso_pin = 4
+};
+const struct driver spi_0 = {
+    .name = "SPI0",
+    .fp = &spi_fp,
+    .dev = &nrf_spi_0
+};
+
 #endif

include/spi.h

@@ -0,0 +1,18 @@
+int spi_open(const struct driver *drv);
+int spi_close(const struct driver *drv);
+
+int spi_write(const struct driver *drv, const char *buffer, unsigned int len);
+
+struct spi {
+    unsigned int sck_pin;
+    unsigned int mosi_pin;
+    unsigned int miso_pin;
+};
+
+static const struct driver_fp spi_fp = {
+    .open = spi_open,
+    .close = spi_close,
+    .read = NULL,
+    .write = spi_write,
+    .ioctl = NULL
+};