[Letux-kernel] LX20 prototype is booting

[Paul Boddie]

On Friday, 2 May 2025 12:45:31 CEST H. Nikolaus Schaller wrote:
> 
> Yes, that looks like what we might need! But it seems to be in place for the
> x2000:
> https://github.com/Ingenic-community/linux/blob/v6.1.y/arch/mips/boot/dts/
ingenic/x2000.dtsi#L113

Admittedly, it was a low-effort suggestion with a potentially high pay-off.

> In the meantime I have analysed further and there is a strange IRQ problem
> with the gpio-keys. I had to disable the boot button hookup completely
> and the wakeup button stops the LED from blinking while it is pressed.
> Seems to be something wrong with the IRQ polarity handling.

[...]

> So I conclude that there is some detail still wrong with interrupt handling,
> especially for gpio keys (maybe the x1600 code for triggering on both
> edges).

The code needs a review, I guess, particularly where codebases have been 
combined in some way.

> Of course it is difficult to do a remote and theoretical analysis...
> Therefore, I should design and build a handful of v0.3 prototypes as soon as
> possible and share with interested developers, like you.

It might be a more productive approach, although you are making good progress 
even with the occasional suggestion.

> What I also have tried is to understand why we have no µSD at all in Linux.
> Well, there was no broken-cd property. But with oscilloscope I only could
> see the MMC clock (~22 MHz) but no other activity.
> 
> The x2000.dtsi requests an ingenic,x2000-sdhci driver. This is only
> available in the sudomaker-6.1.28 kernel and missing in our 6.15 - but it
> is not even confirmed and compiled for the 6.1.28 kernel
> (CONFIG_MMC_SDHCI_INGENIC=n). This explains why neither kernel has µSD...
> I'll try to fix in 6.1.28 first and then forward-port.

I think the SD peripheral is one of those that is different in the X2000. I 
just found another mail from February 2024 where I noted this, along with the 
different LCD controller, although that is not something that we are 
exercising in the near future, I imagine.

Paul