SPI on RTEMS RPi BSP (4.12)

William Busacker wbusacker at outlook.com
Tue Nov 14 07:21:19 UTC 2017

Hello All,

I am trying to get a minimum working example for using SPI on the 
raspberry pi, however I have been unable to get anything on the SPI 
ports for several weeks now.

I have tried using the Linux spidev library as recommended by the user 
guide, however that fails to work. The function calls don't send any 
errors out, however nothing happens (I've been checking both SPI port 
pins for activity). A similar thing happens when I run the spi test 
program located at rtems-git/testsuites/libtests/spi01 in the RTEMS 
source distribution. None of the assertions fail, but again, nothing 
happens on either SPI Bus.

Following the GSoC submission for SPI on the RPi 
(https://devel.rtems.org/wiki/GSoC/2013/Raspberry_Pi_BSP_Peripherals) it 
says that those steps should enable the board to run SPI, however I am 
unable to replicate his results of proof that SPI works. The autotools 
parts in the git repo linked on that page won't run as configure.ac is 
missing. Admittedly my knowledge of autotools is rather limited so that 
may simply be operator error, but the effort that I've put into getting 
this working is telling me there has got to be a better way.

All I really want is a short list of functions to call and parameters to 
pass in for spi control and then a simple rx and tx subroutine (hence my 
first attempt at using spidev).

Any advice or help would be much appreciated,
Will Busacker

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