Read the articles...

• "SPI on Apache NuttX OS"

• "LoRa SX1262 on Apache NuttX OS"

• "LoRaWAN on Apache NuttX OS"

To install the SPI Test Driver in your NuttX project...

1. Copy the files...

   • Kconfig

   • spi_test_driver.c

   To the folder nuttx/drivers/rf

2. Update the NuttX Build Config...

   ## TODO: Change this to the path of our "incubator-nuttx" folder
   cd nuttx/nuttx
   
   ## Preserve the Build Config
   cp .config ../config
   
   ## Erase the Build Config and Kconfig files
   make distclean
   
   ## For BL602: Configure the build for BL602
   ./tools/configure.sh bl602evb:nsh
   
   ## For ESP32: Configure the build for ESP32.
   ## TODO: Change "esp32-devkitc" to our ESP32 board.
   ./tools/configure.sh esp32-devkitc:nsh
   
   ## Restore the Build Config
   cp ../config .config
   
   ## Edit the Build Config
   make menuconfig 

3. In menuconfig...

   • Enable the SPI Port (SPI0)

   • Enable the SPI Character Driver

   • Enable the SPI Test Driver

   As explained here...

   "Load the SPI Test Driver"

4. Edit the function bl602_bringup or esp32_bringup in this file...

   ## For BL602:
   nuttx/boards/risc-v/bl602/bl602evb/src/bl602_bringup.c
   
   ## For ESP32: Change "esp32-devkitc" to our ESP32 board 
   nuttx/boards/xtensa/esp32/esp32-devkitc/src/esp32_bringup.c
   

   And call spi_test_driver_register to register our SPI Test Driver.

   (See this)

5. The SPI Test Driver is accessible by NuttX Apps as "/dev/spitest0"