PocketBeagle SPI device nodes

My PocketBeagle, running a custom 4.9.57 kernel and standard device tree, creates the following SPI device nodes:

usbgadget# ls -l /dev/spi*
crw-rw---- 1 root gpio 153, 0 Jan 1 00:00 /dev/spidev1.0
crw-rw---- 1 root gpio 153, 1 Jan 1 00:00 /dev/spidev1.1
crw-rw---- 1 root gpio 153, 2 Jan 1 00:00 /dev/spidev2.0
crw-rw---- 1 root gpio 153, 3 Jan 1 00:00 /dev/spidev2.1

Why are there four device nodes? Normally there should be a single device node for each slave select, and the
PocketBeagle pinout only lists one slave select for each SPI bus controller.

Which device nodes correspond to which slave selects? (It appears to me that spidev1.x might correspond to McSPIO0
and spidev2.x might correspond to McSPI1).

Phil

There are 4 listed, because i have not yet removed the two
chipselect's that are not available.

spi@48030000 at chipselect 0
spi@481a0000 at chipselect 1

patches welcome.

Regards,