Re: Raspberry Pi POE+ hat overlay

Yes - I copied it from a random Linux distro I had lying around:

$ ls /boot/msdos/overlays
disable-bt.dtbo   mmc.dtbo          pwm.dtbo          rpi-poe-plus.dtbo

I'm wondering if it's something to so with the compatible settings on the
overlay. Disassembling it with dtc looks like this:

/dts-v1/;

/  {

        compatible = "brcm,bcm2835";
        fragment@0 {

                target-path = "/";
                __overlay__ {

                        pwm-fan {

                                compatible = "pwm-fan";
                                cooling-levels = <0x0 0x20 0x40 0x80 0xff>;
                                #cooling-cells = <0x2>;
                                pwms = <0x1 0x0 0x13880>;
                                phandle = <0x3>;
                        };
                };
        };
...

On Fri, 12 May 2023 at 17:09, Emmanuel Vadot <[email protected]> wrote:

> 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]>
>