I have a device designed for RPi that supports SPI.
The software for this device provided by the vendor relies on /dev/spidev0.0 for communication, ie. it's a user space lib.
What's confusing is that /dev/spidev0.0 (and incidentally /dev/spidev0.1) is created on boot even though SPI is not enabled in raspi-config.
Case 1 - SPI enabled in raspi-config: - /dev/spidev0.x appear whether or not device is attached
Case 2 - SPI disabled in raspi-config: - /dev/spidev0.x appears only if device is attached
I am not aware of any plug-and-play for SPI, so am confused why these character devices appear automatically in case 2 when the device is attached.
Note that there is no vendor driver installed (kernel module etc). This is a clean Raspbian dist.
Please help me understand what is happening or where to look further!