Re: [PATCH 3/9] regulator: mt6358: Merge VCN33_* regulators

Conor Dooley
2023-06-12T17:35:23Z

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On Mon, Jun 12, 2023 at 12:19:01PM +0800, Chen-Yu Tsai wrote:
> On Sat, Jun 10, 2023 at 11:28 PM Conor Dooley <conor@kernel.org> wrote:

> > Ah, I see in the binding commit there's a "Luckily no device tree actually
> > uses them." Does that just cover the kernel, or does it consider other
> > operating systems/bootloaders?
>
> That comment covers the upstream kernel and the downstream ChromeOS kernel
> specifically. The bootloader that ChromeOS uses (coreboot) doesn't use
> device trees. I don't know what MediaTek uses for their phones though.
>
> AFAIK MediaTek only supports the Linux kernel, be it for Android or ChromeOS.
> There's not a large community around it, unlike some of the other ARM SoCs.
>
> I did find an old v4.4 Android kernel [1] for the MediaTek Helio P60
> (MT6771) that is also paired with MT6358. There are no device tree
> references to the VCN33 regulator either. Only the definition exists
> in the mt6358.dtsi file, much like what we have upstream.
>
> As far as the regulator driver goes, if it can't find a matching regulator
> node, it's the same as if the node doesn't exist, and therefore the given
> constraints are not ingested. If no constraints are ingested that can
> turn it on, and no consumer references to enable it either, we can say
> that the regulator is effectively unused.

Okay, that sounds reasonable. Seems like you've done your research,
so thanks for that!

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