Device Tree Overlays
--------------------

How to use
==========

Add dtoverlay=<overlay> (without the .dtbo) to /etc/default/raspi-firmware-custom and run:

DEB_MAINT_PARAMS=configure /etc/kernel/postinst.d/z50-raspi-firmware

Hifiberry Beocreate
===================

force_eeprom_read=0
dtoverlay=pi4-spidev
dtoverlay=hifiberry-dac

Raspberry POE+ Hat
==================

To make the fan on the POE+ hat run depending on the CPU's core temperature add

```
dtoverlay=rpi-poe-plus-hat
```

to `/etc/default/raspi-firmware-custom`. The fan's speed is set depending on the
reported CPU temperature. The default trip points are: 40°C, 45°C, 50°C and
55°C. Those can be overwritten using e.g.

```
dtoverlay=rpi-poe-plus-hat,poe_fan_temp0=44500,poe_fan_temp1=47000
```

The unit is in °mC, use `poe_fan_temp2` and `poe_fan_temp3` for the 3rd and 4th
trip point.

Raspberry PI4 PWM
=================

To expose the two PWM channels of the pwm@7e20c000 device add

```
dtoverlay=pi4-pwm
```

to `/etc/default/raspi-firmware-custom`. This routes the two PWM channels to
GPIO12 (aka pin 32) and GPIO13 (aka pin 33). Use

```
dtoverlay=pi4-pwm,pwmalt
```

to route them to the alternative pins GPIO18 (pin 12) and GPIO19 (pin 35).
