Re: Raspberry Pi POE+ hat overlay

On Fri, 12 May 2023 16:43:55 +0100
Doug Rabson <[email protected]> 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?

DT Overlays works fine, the process of them on RPI is:

 - Firmware loads the DTB
 - Parse the config.txt and load/apply the overlays
 - The DTB is passed to u-boot which in turn pass it to loader/kernel

 Stupid question but did you copy the rpi-poe-plus.dtbo on the fat
partition ?

-- 
Emmanuel Vadot <[email protected]> <[email protected]>