Adding support for Zyxel GS1900-48HPv2

[Sander Vanheule]

Hi Kirill,

On Fri, 2025-11-21 at 00:16 +0300, Deeily wrote:
> Hello OpenWrt developers,
> 
> I am writing to contribute a preliminary device tree source (DTS) file
> for the Zyxel GS1900-48HP switch. I am a beginner in this area, but I
> managed to create a working DTS by using the DTS for the GS1900-24HPv2
> model as a base.

To submit patches, also as a request for comments (RFC), please have a look at
https://openwrt.org/submitting-patches

GitHub is the most popular platform, but you can still submit patches via mail
if you prefer so. Please use "git format-patch" to mail changes, rather than
attaching files, as attachments are harder to review. See
https://www.kernel.org/doc/html/latest/process/submitting-patches.html#the-canonical-patch-format

> 
> With this DTS, the device boots and basic switching functionality
> works. Power over Ethernet (PoE) is supplied on all 24 PoE-capable
> ports, however, I have identified a significant issue with PoE
> management:
> 
>     PoE Control Issue: Currently, it is only possible to control the
> power (on/off) for the first PoE port (port 0). The remaining 23 PoE
> ports are always on and cannot be managed via software.
> 
> I understand that this is an incomplete patch and the PoE control
> needs to be fixed. However, I am providing it as a starting point. I
> am willing to help in any way I can.

You have a "realtek,poe-mcu" node in your DT, but AFAIK that's not actually a
thing that has a driver. If you are using the realtek-poe package, you need to
make sure you have a device entry for realtek_setup_poe() in
target/linux/realtek/base-files/etc/board.d/02_network. Otherwise realtek-poe
cannot generate a proper config file (it used to default to a config file with
only port 1) and you have to create it manually.

For the PoE LEDs, you indicate in the DTS that these are driven by the RTL8231,
but you didn't provide any LED nodes, nor did you provide any pinctrl settings
to correctly mux the required pins to the LED controller. Is this just a
placeholder?

If you do submit an RFC on GitHub or via mail, please try be complete about what
is working, what isn't, and which things you haven't tested yet.


Best,
Sander