Cannot use SPI on jetson Nano (cannot see /dev/spidev)

On my nano, even after using I cannot see the spidev in the /dev directory:
I invoke sudo /opt/nvidia/jetson-io/ and expose the two SPI ports. Everything OK and I save and reboot.
But no spi device in /dev/spidev…
If I relaunch, I can see that the 2 SPI are selected (so well taken into account)
Any idea why ?

As nobody seems to have an answer I dug a little deeper and I found that it is necessary to “expose” the spi ports with sudo modprobe spidev.
To summarize :

  • launch
  • select the ports spi (spi& and/or spi2) you want to use
  • sudo modprobe spidev

…It’s time for Nvidia to decide to write practical and simple user guides…This would avoid wasting time to find out things.

Please run below command to load SPIDEV driver.

sudo modprobe spidev

I have also been struggling with getting some results from the SPI bus. I have used the loopback test with ./spidev_test -v and got some good results in terms of identical TX and RX which suggests I have things set up correctly. I am perhaps expecting too much for spidev to provide a reasonably simple API to allow me to write a byte or two and read some responses from a simple SPI sensor BME280. I can see some responses on the logic analyser though they do not look very much like SPI waveforms from other platforms. Have others got the Nano spi port working well?