Raspberry Pi HATs
This page will be used to document using various HATs on the Raspberry Pi. Please feel free to add notes pertaining to other HATs or additions to the existing entries.
For all HATs
To use HATs in Fedora, first remove the symlink for the dtb. This forces the system to use the firmware provided dtb rather than the kernel specific dtb installed with Fedora kernels. The firmware provided dtb should provide the same functionality.
Remove the symlink:
rm /boot/dtb
Prevent the symlink from being recreated on kernel upgrade.
echo "FirmwareDT=True" >> /etc/u-boot.conf
You now need to add the overlay for the HAT to the '/boot/efi/config.txt'. Below are some examples.
Sense Hat
Edit the '/boot/efi/config.txt' to add the overlay
dtoverlay=rpi-sense
Working
- Humidity Sensor (hts221)
- Barometer (lps25h)
- Magnetometer (lsm9ds1_magn)
- Temperature (hts221, lps25h)
Not Working
- 8x8 LED matrix display
- Small 5 button joystick
Adafruit PiTFT Plus (3.5 inch Resistive Touch screen)
To use the screen you will need to install 'bcm283x-firmware-20191118-1.68ec481.fc31' or later. To use the touch features of the screen you also need to install 'kernel-5.4.0-0.rc8.git0.1.fc32' or later.
Edit the '/boot/efi/config.txt' to add the overlay
dtparam=i2c_arm=on dtoverlay=pitft35-resistive hdmi_force_hotplug=1
Add to the kernel parameters
fbcon=map:10 fbcon=font:ProFont6x11
Due to a bug the kernel module will not load automatically. On boot the module can be loaded with:
modprobe hx8357d
Due to a bug with the VC4 driver you will also need to blacklist it:
echo "blacklist vc4" >> /etc/modprobe.d/blacklist-vc4.conf
To workaround the bug and have it load automatically use:
echo hx8357d >> /etc/modules-load.d/hx8357d.conf