Raspberry Pi zero 2 dtb and devices

[Dave Tyson <dtyson%anduin.org.uk@localhost>]

I have been testing a rpi zero 2 with a view to use it as a weather station 
controller. I used Jun Ebihara's image and that boots and runs fine. As I 
noted in a post on tech-kern there are three i2c interfaces listed in dmesg - 
but only two work iic1 and iic2. I have no idea what iic0 points to.

Sadly there are no spi devices defined, no gpio interface and no wireless 
support for the on-board chip.

I note that the image uses the rpi 3-b-plus dtb with the board - a few linux 
discussions mention this for booting a 64bit o/s. More recently the raspios-
bullseye-arm64-lite linux image seems to use the 'native' dtb and that boots 
OK with the i2c, spi, gpio and wifi working. It's a shame that even the lite 
version has a shed load of crap and systemd :-(

I did try to use this dtb against the armv7.img and it boots OK. Sadly there 
is only one iic interface and that fails to work (gives I/O errors). The wifi 
seems to load drivers and fails due to a missing clock. There is an error 
message about the iicmux which might explain the problems and again there is 
no sign of any spi or gpio interfaces.

So it looks like something is amiss when NetBSD parses and instanciates the 
dtb. I haven't found where the hooks are that parse the dtb and somehow use 
the files.dtb to attach devices so far.

The relevant dmesg for the boot with rpi-3-b-plus dtb, rpi-zero-2-w dtb and 
linux are at:
 
https://penkett.anduin.org.uk/~dtyson/netbsd/ 
 
Any help appreciated.
 
Dave