[PATCH v4 0/8] Add support for ZTE zx297520v3

[Stefan Dösinger]

Hi,

This is a follow-up on my RFC patches from January [0] for ZTE's 
zx297520v3 chipset. This chipset is popular in cheap LTE-to-wifi routers 
sold in developing countries. My goal is to run OpenWRT on them. I made 
more progress in more work on this SoC and it is time to get serious 
about code review and upstreaming.

Since my version in January I managed to get more hardware running: SPI, 
I2C, PMIC with real time clock and voltage regulators, Watchdog. LTE is 
not working yet, but I am able to start the coprocessor that handles it 
and talk to it via mailbox + shared memory. Wifi is working on a few 
more devices. Since WiFi, USB and Ethernet are working, the devices can 
have actual use with OpenWRT even without LTE.

Another hacker created a free software program to talk to the USB loader 
[1] and boot U-Boot and Linux without modifying the on disk files. At 
the moment it needs a proprietary blob, so my documentation is 
emphasising booting with the on-device U-Boot.

This patchset here is mostly unmodified from the version I sent in 
January. It is the bare minimum to get an interactive shell working on 
the UART. Future patches can be found on my git repository [2] for those 
curious to peek ahead. The first 30 patches are in reasonable shape, but 
the further you go the more cleanup is necessary. I expect all of the 
patches go require a few rounds of feedback though.

My plan for upstreaming is largly this:

1) This bare minimum boot patchset
2) Add clock and pinctrl drivers
3) Add standard hardware to the device tree
4) Add zx29 specific drivers one by one: Watchdog, spi, i2c, DMA, PMIC, 
battery
5) SDIO backend for rtl8xxxu
6) rproc, mailbox and rpmsg

I am willing to maintain support for the SoC within reason. My patches 
add myself as maintainer. This is a hobby project for me though, keep 
that in mind if you want to ship a commercial product with these SoCs 
and upstreaming Linux.

Cheers,
Stefan

0: https://lists.infradead.org/pipermail/linux-arm-kernel/2026-January/1099306.html
1: https://github.com/zx297520v3-mainline/zx297520v3-loader
2: https://gitlab.com/stefandoesinger/zx297520-kernel/

Patch changelog:

v4: rename zx29.yaml to zte.yaml and add board enums
v3: Remove [RFC] tag, add defconfig
v2: checkpatch.pl fixes

Signed-off-by: Stefan Dösinger <stefandoesinger at gmail.com>
---
Stefan Dösinger (8):
      ARM: zte: Add zx297520v3 platform support
      dt-bindings: arm: Add zx297520v3 board binding
      ARM: dts: Add D-Link DWR-932M support
      ARM: zte: Add support for zx29 low level debug
      ARM: dts: Add an armv7 timer for zx297520v3
      ARM: zte: Bring back zx29 UART support
      ARM: dts: Declare UART1 on zx297520v3 boards
      ARM: defconfig: Add a zx29 defconfig file

 Documentation/arch/arm/zte/zx297520v3.rst      | 158 +++++++++++++++++++++++++
 Documentation/devicetree/bindings/arm/zte.yaml |  25 ++++
 MAINTAINERS                                    |   6 +
 arch/arm/Kconfig                               |   2 +
 arch/arm/Kconfig.debug                         |  12 ++
 arch/arm/Makefile                              |   1 +
 arch/arm/boot/dts/Makefile                     |   1 +
 arch/arm/boot/dts/zte/Makefile                 |   3 +
 arch/arm/boot/dts/zte/dlink-dwr-932m.dts       |  21 ++++
 arch/arm/boot/dts/zte/zx297520v3.dtsi          |  83 +++++++++++++
 arch/arm/configs/zx29_defconfig                |  90 ++++++++++++++
 arch/arm/include/debug/pl01x.S                 |   7 ++
 arch/arm/mach-zte/Kconfig                      |  24 ++++
 arch/arm/mach-zte/Makefile                     |   2 +
 arch/arm/mach-zte/zx297520v3.c                 |  19 +++
 drivers/tty/serial/amba-pl011.c                |  37 ++++++
 include/linux/amba/bus.h                       |   6 +
 17 files changed, 497 insertions(+)
---
base-commit: 028ef9c96e96197026887c0f092424679298aae8
change-id: 20260416-send-5c08e095e5c9

Best regards,
-- 
Stefan Dösinger <stefandoesinger at gmail.com>