Support for reTerminal display and peripherals

[aanrudolph2]

I'm not sure how to add in additional driver sources here, in this case for a reTerminal display and peripherals (https://wiki.seeedstudio.com/reTerminal/). SeeedStudio provides a DKMS module for Raspberry Pi OS, which suggests this can be added -- see https://github.com/Seeed-Studio/seeed-linux-dtoverlays/.

The benefit is that this is a fully featured device with an accelerometer, light sensor, and buttons that can be utilized in Android OS.

[KonstaT]

I'm not aware of any easy solution for building out-of-tree kernel modules for Android.

Since you can't compile the kernel on the Android device, you need to cross-compile the Android kernel on some other host machine. You could add the specific drivers to the kernel source but you'd probably also need to add relevant Kconfig and Makefile entries. There's kernel build instructions available here.
https://github.com/raspberry-vanilla/android_kernel_manifest

AOSP kernel build environment supports building external modules as that's how hardware support is implemented on devices that use Android GKI (generic kernel image). This is not used on my Raspberry Pi builds. You can check e.g. common-modules directory on the kernel build env and reference other devices that use it. You'd still need to make some adjustments to the driver source and the rpi4 build configuration to use this. Even if you manage to get a module built, getting it loaded is another topic. My kernel builds include all the necessary drivers built into the kernel image itself (no modules are used).

Just by adding a kernel driver for e.g. accelerometer or light sensor doesn't utilize it in Android. You would need to add Android sensor HAL for that purpose. Raspberry Vanilla doesn't include support for such external hardware but you can find the source code for IIO sensor HAL used in my LineageOS/personal AOSP builds here.
https://github.com/lineage-rpi/android_hardware_intel_sensors-iio

Here is some discussion related to adding additional sensor support.
lineage-rpi/android_kernel_brcm_rpi#28
http://disq.us/p/2w873fx

[KonstaT]

Closing as there has been no activity on this issue for a month.

Goal of the Raspberry Vanilla project is to provide support for the built-in hardware on Raspberry Pi.