Hi Guix! (Re-posting from help-g...@gnu.org as I didn't get any answers there.)
I'm starting a small embedded project using a Rock64, successfully running Guix on it (and keeping track of config at [0]). It seems that the Rock64 has a few design mistakes (as always I guess, but in this case they matter to me), such that I would need to use a tiny devicetree overlay to get access to the board's SPI device. The pine64 forum has a couple threads on this: [1] [2]. Trying to use the kernel's configfs to set up an overlay (as in the first thread above, [1]) doesn't seem possible, as the devicetree in configfs seems to be only made available on board-maintained versions of the kernel [3]. My question: is there a standard way to change a devicetree using Guix's bootloader+kernel tooling? U-Boot's docs [4] mention either manually loading an overlay, or putting it in a Flat Image Tree, but I haven't figured out how to do that with Guix's tooling. I'm also not understanding whether I would need to do this for both u-boot and the kernel, or if the first would be enough. This thread [5] from help-guix mentions it would be nice to be able to parse custom devicetrees, but that wasn't enough to find next steps in exploring this. Do guixers have experience that could help here? Any hints or help would be very welcome! Happy hacking -- and please let me know if this doesn't belong on this list, Sébastien [0] https://gitlab.com/wehlutyk/matrixbox/ [1] https://forum.pine64.org/showthread.php?tid=6282&pid=40056#pid40056 [2] https://forum.pine64.org/showthread.php?tid=5522 [3] https://stackoverflow.com/questions/50877808/configfs-do-not-mount-device-tree-overlays [4] https://u-boot.readthedocs.io/en/stable/usage/fdt_overlays.html#ways-to-utilize-overlays-in-u-boot [5] https://mail.gnu.org/archive/html/help-guix/2020-04/msg00052.html PS: in case anybody is interested, the project is to implement a Marble Answering Machine <https://vimeo.com/183465991> on top of Matrix, with added message-sending buttons, to enable young children (and grown-ups) to message friends and relatives while still avoiding screen exposure.