Let's test the #NuttX SPI Driver for #BL602
https://nuttx.apache.org/docs/latest/components/drivers/special/spi.html
Fixing our "spi_test" app for #NuttX ... Rename "hello_main.c" to "spi_test_main.c"
https://github.com/lupyuen/incubator-nuttx-apps/commit/a4f884c67dc4c1042831d0554aed1d55a0e28b40
1️⃣ make distclean 2️⃣ configure.sh 3️⃣ make menuconfig ... Our #NuttX App "spi_test" magically appears!
https://github.com/lupyuen/incubator-nuttx-apps/tree/newapp/examples/spi_test
Our #NuttX Demo App "spi_test" ... Runs OK on #BL602
https://github.com/lupyuen/incubator-nuttx-apps/blob/newapp/examples/spi_test/spi_test_main.c
#NuttX SPI Interface is defined here ... Let's call it from our "spi_test" app
https://github.com/apache/incubator-nuttx/blob/master/include/nuttx/spi/spi.h
Build, Flash and Run #NuttX OS on #BL602 ... Here's the script I use for macOS
https://gist.github.com/lupyuen/cc21385ecc66b5c02d15affd776a64af
Can our #NuttX App directly call the SPI Interface? Let's find out! 🤔
https://github.com/lupyuen/incubator-nuttx-apps/blob/spi_test/examples/spi_test/spi_test_main.c
#NuttX SPI Interface needs an SPI Device "spi_dev_s" ... How do we get an SPI Device? 🤔
https://github.com/lupyuen/incubator-nuttx/blob/master/arch/risc-v/src/bl602/bl602_spi.c#L932-L967
Tracing thru #NuttX Virtual File System ... We see that ioctl() maps the File Descriptor to a File Struct
https://github.com/lupyuen/incubator-nuttx/blob/master/fs/vfs/fs_ioctl.c#L118-L138
#NuttX File Struct contains a Private Pointer to the SPI Driver "spi_driver_s"
https://github.com/lupyuen/incubator-nuttx/blob/master/drivers/spi/spi_driver.c#L112-L147
#NuttX SPI Driver "spi_driver_s" contains the SPI Device "spi_dev_s" ... That we need for testing the SPI Interface! But the SPI Device is private and hidden from apps 🙁
https://github.com/lupyuen/incubator-nuttx/blob/master/drivers/spi/spi_driver.c#L55-L65
Instead we copy an existing #NuttX SPI Device Driver to test the SPI Interface ... We pick the simplest smallest SPI Device Driver: dat-31r5-sp
https://docs.google.com/spreadsheets/d/1MDps5cPe7tIgCL1Cz98iVccJAUJq1lgctpKgg9OwztI/edit#gid=0
We create a new #NuttX SPI Device Driver ... By copying "dat-31r5-sp.c" to "spi_test_driver.c"
https://github.com/lupyuen/incubator-nuttx/blob/newdriver/drivers/rf/spi_test_driver.c
In our SPI Test Driver: Change all "dat31r5sp" to "spi_test_driver" ... Remember to Preserve Case!
https://github.com/lupyuen/incubator-nuttx/commit/8fee69215163180b77dc9d5b9e7449ebe00ac1cc
Do the same to create the Header File for our #NuttX Driver: spi_test_driver.h
https://github.com/lupyuen/incubator-nuttx/blob/newdriver/include/nuttx/rf/spi_test_driver.h
Add our SPI Test Driver to #NuttX Kconfig
https://github.com/lupyuen/incubator-nuttx/blob/newdriver/drivers/rf/Kconfig#L22-L27
Our SPI Test Driver for #NuttX appears in "make menuconfig"!
https://github.com/lupyuen/incubator-nuttx/blob/newdriver/drivers/rf/Kconfig#L22-L27
Remember to enable "SPI0" and "SPI Character Driver" in #NuttX ... Or our SPI Test Driver won't start
https://github.com/lupyuen/incubator-nuttx/blob/newdriver/drivers/rf/spi_test_driver.c
Here's what happens when we make a boo-boo and #NuttX won't start
https://gist.github.com/lupyuen/ccfd90125f9a180b4cfb459e8a57b323
In our #NuttX App "spi_test", change all "hello" to "spi_test" ... Remember to Preserve Case!
https://github.com/lupyuen/incubator-nuttx-apps/commit/0e19613b3059882f002eee948c0a79f622eccb74