cpu: samd21: use periph_common SPI functions

cpu/samd21/Makefile.include

@@ -6,4 +6,7 @@ export CFLAGS += -DDONT_USE_CMSIS_INIT
 # use the hwtimer compatibility layer
 USEMODULE += hwtimer_compat
 
+# use common periph functions
+USEMODULE += periph_common
+
 include $(RIOTCPU)/Makefile.include.cortexm_common

cpu/samd21/include/periph_cpu.h

@@ -88,6 +88,15 @@ typedef enum {
  */
 int gpio_init_mux(gpio_t dev, gpio_mux_t mux);
 
+/**
+ * @brief declare needed generic SPI functions
+ * @{
+ */
+#define PERIPH_SPI_NEEDS_TRANSFER_BYTES
+#define PERIPH_SPI_NEEDS_TRANSFER_REG
+#define PERIPH_SPI_NEEDS_TRANSFER_REGS
+/** @} */
+
 #ifdef __cplusplus
 }
 #endif

cpu/samd21/periph/spi.c

@@ -258,47 +258,6 @@ int spi_transfer_byte(spi_t dev, char out, char *in)
     return 1;
 }
 
-int spi_transfer_bytes(spi_t dev, char *out, char *in, unsigned int length)
-{
-    int transfered = 0;
-
-    if (out != NULL) {
-        DEBUG("out*: %p out: %x length: %x\n", out, *out, length);
-        while (length--) {
-            int ret = spi_transfer_byte(dev, *(out)++, 0);
-            if (ret <  0) {
-                return ret;
-            }
-            transfered += ret;
-        }
-    }
-    if (in != NULL) {
-        while (length--) {
-            int ret = spi_transfer_byte(dev, 0, in++);
-            if (ret <  0) {
-                return ret;
-            }
-            transfered += ret;
-        }
-        DEBUG("in*: %p in: %x transfered: %x\n", in, *(in-transfered), transfered);
-    }
-
-    DEBUG("sent %x byte(s)\n", transfered);
-    return transfered;
-}
-
-int spi_transfer_reg(spi_t dev, uint8_t reg, char out, char *in)
-{
-    spi_transfer_byte(dev, reg, NULL);
-    return spi_transfer_byte(dev, out, in);
-}
-
-int spi_transfer_regs(spi_t dev, uint8_t reg, char *out, char *in, unsigned int length)
-{
-    spi_transfer_byte(dev, reg, NULL);
-    return spi_transfer_bytes(dev, out, in, length);
-}
-
 void spi_poweron(spi_t dev)
 {
     switch(dev) {