On Wed, Aug 3, 2022 at 4:17 PM Steven A. Falco <stevenfalco@xxxxxxxxx> wrote: > > I have a Pi4B that is working pretty well with the aarch64 version of Fedora Rawhide, but I have one issue that I haven't been able to find a solution to. > > I have an Adafruit RTC connected via I2C (https://www.adafruit.com/product/3386). If I use the kernel device tree, this device is not found. > > I then tried switching to the firmware device tree via the instructions in https://fedoraproject.org/wiki/Architectures/ARM/Raspberry_Pi/HATs. That works pretty well - I can now add an overlay for the RTC in /boot/efi/config.txt and the RTC is found during boot. dtoverlay=i2c-rtc,pcf8523,addr=0x68 > > However, once I've switched to the firmware device tree, I no longer have /dev/vchiq, which means that I can no longer use vcgencmd. Instead, vcgencmd gives me "VCHI initialization failed". It should be the same as required in Raspbian. Have you checked the details in /boot/efi/overlays/README? Out of interest what do you use /dev/vchiq / vcgencmd for? > Is there any way to get both the RTC and vcgencmd to work? Which device tree would I choose? Do I have to build a custom kernel or is there some other way to enable the RTC with the kernel device tree? You don't need a custom kernel but you'd need to build your own DT as obviously anything that is not default on the RPi devices themselves is optional hence the requirement of overlays. _______________________________________________ arm mailing list -- arm@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to arm-leave@xxxxxxxxxxxxxxxxxxxxxxx Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/arm@xxxxxxxxxxxxxxxxxxxxxxx Do not reply to spam, report it: https://pagure.io/fedora-infrastructure/new_issue
