Re: Raspberry Pi POE+ hat overlay

On May 12, 2023, at 08:43, Doug Rabson <dfr@rabson.org> wrote:

> I have a pi4 with the official POE+ hat which I want to run FreeBSD on. One thing I noticed is that the fan doesn't run in FreeBSD so I decided to try and write a little driver for it. First step seems to be to load the corresponding devicetree overlay by adding something like this to /boot/msdos/config.txt:
> 
> dtoverlay=rpi-poe-plus
> dtparam=poe_fan_temp0=45000,dtparam=poe_fan_temp0_hyst=3000
> dtparam=poe_fan_temp1=50000,dtparam=poe_fan_temp1_hyst=3000
> dtparam=poe_fan_temp2=62000,dtparam=poe_fan_temp2_hyst=4000
> dtparam=poe_fan_temp3=70000,dtparam=poe_fan_temp3_hyst=5000
> 
> Unfortunately this is where I'm stuck - the overlay is not present in the final DTB given to the kernel so there isn't anything to hook a driver to. Are dtoverlays supposed to work on FreeBSD?

The RPi* firwmare version that FreeBSD has in ports and uses
in making snapshots and other images does not have that overlay:

# ls -Tld /usr/local/share/rpi-firmware/overlays/rpi*
-rw-r--r--  1 root  wheel   489 Mar  3 05:29:57 2021 /usr/local/share/rpi-firmware/overlays/rpi-backlight.dtbo
-rw-r--r--  1 root  wheel  4081 Mar  3 05:29:57 2021 /usr/local/share/rpi-firmware/overlays/rpi-cirrus-wm5102.dtbo
-rw-r--r--  1 root  wheel   643 Mar  3 05:29:57 2021 /usr/local/share/rpi-firmware/overlays/rpi-dac.dtbo
-rw-r--r--  1 root  wheel  2574 Mar  3 05:29:57 2021 /usr/local/share/rpi-firmware/overlays/rpi-display.dtbo
-rw-r--r--  1 root  wheel   842 Mar  3 05:29:57 2021 /usr/local/share/rpi-firmware/overlays/rpi-ft5406.dtbo
-rw-r--r--  1 root  wheel  2937 Mar  3 05:29:57 2021 /usr/local/share/rpi-firmware/overlays/rpi-poe.dtbo
-rw-r--r--  1 root  wheel   771 Mar  3 05:29:57 2021 /usr/local/share/rpi-firmware/overlays/rpi-proto.dtbo
-rw-r--r--  1 root  wheel   893 Mar  3 05:29:57 2021 /usr/local/share/rpi-firmware/overlays/rpi-sense.dtbo
-rw-r--r--  1 root  wheel   567 Mar  3 05:29:57 2021 /usr/local/share/rpi-firmware/overlays/rpi-tv.dtbo
-rw-r--r--  1 root  wheel  1226 Mar  3 05:29:57 2021 /usr/local/share/rpi-firmware/overlays/rpivid-v4l2.dtbo

You do not mention establishing a copy of overlays/rpi-poe-plus.dtbo .

You also do not mention what version of FreeBSD you are using
on the RPi4B. The output of the command:

# uname -apKU

would indicate the branch and version of the kernel in use and
some more. This can be relevant to what sort of experimental
(unsupported) RPi* firmware configurations can be used.

===
Mark Millard
marklmi at yahoo.com