[BUG] Raxda Rock Pi 4A serial console output stops prematurely

[Quentin Schulz]

Hi Heinrich,

On 11/25/25 7:02 PM, Heinrich Schuchardt wrote:
> Hello Jagan, hello Heiko,
> 
> When testing U-Boot origin/master on my Raxda Rock Pi 4A serial console 
> output stops after "PMIC:  RK808". The same can be observed with v2025.01.
> 
> The serial console works as expected if I disable CONFIG_ROCKCHIP_IODOMAIN.
> 

It is I believe implied here but asking for confirmation. The board 
doesn't actually boot right? It's not that the serial console is gone, 
it's that the device is stuck?

> The problem seems to be specifically related to the bt656-supply. 
> Removing the line below also fixes serial console output:
> 
> diff --git a/drivers/misc/rockchip-io-domain.c b/drivers/misc/rockchip- 
> io-domain.c
> index a0573c52193..b0d78f2d4b4 100644
> --- a/drivers/misc/rockchip-io-domain.c
> +++ b/drivers/misc/rockchip-io-domain.c
> @@ -239,7 +239,7 @@ static const struct rockchip_iodomain_soc_data 
> soc_data_rk3328 = {
>   static const struct rockchip_iodomain_soc_data soc_data_rk3399 = {
>          .grf_offset = 0xe640,
>          .supply_names = {
> -               "bt656-supply",         /* APIO2_VDD */
> 

The UART2 (which I assume is the serial you're using for the console) 
isn't on that IO domain. And there doesn't seem to be anything important 
to booting on APIO2 domain according to Rock 4A schematics[1].

bt656-supply also doesn't seem to be anything special. LDO5 (vcc_3v0) on 
RK808, which is using VCC10 (vcc10-supply) which is a fixed regulator 
whose parent supply is also a fixed regulator. So I am not sure what 
could be going wrong there.

RK3399 Puma and RockPro64 have APIO2 set to 1.8V vs 3.0V for Radxa Rock 
4A. Puma boots master reaches U-Boot CLI with the IO domain driver 
compiled in.

Can you check the error paths (all the ones with a continue;) in 
rockchip_iodomain_probe()? Which ones do you enter for which supply?

Not sure where to start debugging tbh.

[1] https://dl.radxa.com/rockpi4/docs/hw/rockpi4/4a/ROCK_4A_V1.52_SCH.pdf

Cheers,
Quentin