Aw: Re: [PATCH v1 0/4] add syscon requirement for mt7988

[Frank Wunderlich]

Hi

> Gesendet: Mittwoch, 10. Juli 2024 um 12:45 Uhr
> Von: "AngeloGioacchino Del Regno" <angelogioacchino.delregno at collabora.com>
> Betreff: Re: [PATCH v1 0/4] add syscon requirement for mt7988
>
> Il 09/07/24 12:13, Frank Wunderlich ha scritto:
> > From: Frank Wunderlich <frank-w at public-files.de>
> >
> > Some nodes require the syscon fallback at least in u-boot when using
> > OF_UPSTREAM.
> >
> > This is because uboot driver uses syscon_node_to_regmap in mtk_eth.c for
> > "mediatek,toprgu", "mediatek,xfi_pll" and reset pointing to watchdog-node.
> >
>
> I wonder what's the major blocker here to modify the u-boot driver to take
> the upstream devicetree as-is, instead of using syscon_node_to_regmap?

in uboot there is no driver for all syscon and to handle parallel access this is done with the syscon fallback.

The syscon uclass is a small driver which is generic and only handle the regmap in global context.

In theory it could be possible that regmap is aquired twice when used from 2+ other drivers...to prevent this without
adding the syscon fallback each syscon needs a dedicated driver like in linux which does only syscon stuff (code
duplication at its best :) ).

of course i can use regmap_init_mem in the uboot ethernet driver

https://elixir.bootlin.com/u-boot/latest/source/drivers/core/regmap.c#L242

like it's done once for syscon-uclass.

but i will cause issues when a second device tries to access this regmap. So it was be much easier (for me) to add this
fallback and not writing 3 device-drivers in uboot doing the exactly same as syscon.

if you have a better idea how to handle it, let me know :)

regards Frank

> Regards,
> Angelo