bsps/include/dev/spi: Add missing extern and guard

This adds missing extern "C" declarations and a missing header guard.

bsps/include/dev/spi/cadence-spi-regs.h

@@ -30,6 +30,10 @@
 
 #include <bsp/utility.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 typedef struct {
     uint32_t config;
 #define CADENCE_SPI_CONFIG_MODEFAIL_EN BSP_BIT32(17)
@@ -82,4 +86,8 @@ typedef struct {
 	uint32_t moduleid;
 } cadence_spi;
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* LIBBSP_ARM_XILINX_ZYNQ_CADENCE_SPI_REGS_H */

bsps/include/dev/spi/xilinx-axi-spi-regs.h

@@ -30,6 +30,10 @@
 
 #include <bsp/utility.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 typedef struct {
     uint32_t reserved1[7];
     uint32_t globalirq;
@@ -85,4 +89,8 @@ typedef struct {
     uint32_t rx_fifo_len;
 } xilinx_axi_spi;
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* LIBBSP_ARM_XILINX_AXI_SPI_REGS_H */

bsps/include/dev/spi/xqspi_flash.h

@@ -31,6 +31,10 @@
 #include <dev/flash/flashdev.h>
 #include <dev/spi/xqspipsu.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #define XQSPI_FLASH_MAX_REGIONS ((size_t)32)
 
 /*
@@ -65,4 +69,8 @@ typedef struct xqspi_flash_region_table {
   uint32_t xqspi_flash_bit_allocator;
 } xqspi_flash_region_table;
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* XILINX_XQSPI_FLASH_H */

bsps/include/dev/spi/xqspipsu-flash-helper.h

@@ -3,8 +3,15 @@
 * SPDX-License-Identifier: MIT
 ******************************************************************************/
 
+#ifndef LIBBSP_DEV_SPI_XQSPIPSU_HELPER_H
+#define LIBBSP_DEV_SPI_XQSPIPSU_HELPER_H
+
 #include "xqspipsu.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 int QspiPsu_NOR_Initialize(
   XQspiPsu *QspiPsuInstancePtr,
   u16 QspiPsuIntrId
@@ -231,3 +238,9 @@ u32 QspiPsu_NOR_Get_Page_Size(XQspiPsu *QspiPsuPtr);
  * @return The JEDEC ID of attached flash in bytes.
  ******************************************************************************/
 u32 QspiPsu_NOR_Get_JEDEC_ID(XQspiPsu *QspiPsuPtr);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* LIBBSP_DEV_SPI_XQSPIPSU_HELPER_H */