How to use NAND and UART3 with latest Linux image for A13-SOM-512

[Christo Radev]

Hi to All,

I have very old A13-SOM-512 and A13-SOM-WIFI-4GB boards and nowadays I have started successfully using them with the latest Olimex image (http://images.olimex.com/release/a13/A13-OLinuXino-bullseye-minimal-20230515-130040.img.7z).

I have to use UART3 and while looking on how to enable it without recompiling the kernel I found that the kernel is compiled with CONFIG_OF_OVERLAY=y. Later on I see that in /usr/lib/olinuxino-overlays/sun5i-a13 have the files to enable UART3. While searching for a guide on how to enable UART3 using overlay blobs I see that there is not enabled NAND support in /usr/lib/linux-image-5.10.105-olimex/sun5i-a13-som-512.dtb.

My questions are:

1. Can I use 4GB NAND chip on A13-SOM-WIFI-4GB board by enabling it in sun5i-a13-som-512 device tree or by an overlay found on https://github.com/armbian/sunxi-DT-overlays/tree/e4dfea8304d66cb3403e5e1b73d2f346349124ec/sun5i-a13?

2. Does LCD have to be disabled for been able to use UART2?

3. Is there a simple guide on how to enable Linux kernel features using overlay device tree blobs (*.dtbo)

Thanks in advance
Christo

[LubOlimex]

1. NAND won't work with mainline images. The drivers are not open-source and community won't make it work. If you wish to use NAND you have to use old kernel sunxi images.

Alternative is to use boards with eMMC. The eMMC has support under mainline kernel images.

There can be some way to get NAND working breaking the open source nature, but we have no experience with it and we don't know what has to be done. It is worth asking elsewhere if that is possible at all.

2. Doesn't seem like it. TWI2 seems to be PB17 and PB18 while LCD uses port D signals. TWI2 is available at GPIO-3 (pins 8 and 10).

3. What we have is the source code for everything we've done for Olimage (overlays, u-boot, kernel, etc, etc) at Olimex GitHub. Also this is good document on Olimage and the end there are some instructions: https://github.com/OLIMEX/OLINUXINO/blob/master/DOCUMENTS/OLIMAGE/Olimage-guide.pdf

[Christo Radev]

Alternative is to use boards with eMMC. The eMMC has support under mainline kernel images.

Does Olimex have a plan to make A13-SOM-WIFI board with eMMC or eMMC Flash Module like one announced for STMP157-OLinuXino-LIME2?