[PATCH v1 0/5] Convert recently merged T30 boards to use DM PMIC

[Svyatoslav Ryhel]

15 листопада 2023 р. 21:11:49 GMT+02:00, Tom Rini <trini at konsulko.com> написав(-ла):
>On Wed, Nov 15, 2023 at 04:51:08PM +0100, Thierry Reding wrote:
>> On Mon, Nov 06, 2023 at 04:04:07PM -0500, Tom Rini wrote:
>> > On Mon, Nov 06, 2023 at 02:11:16PM +0000, Peter Robinson wrote:
>> > > On Mon, Nov 6, 2023 at 1:28 PM Svyatoslav Ryhel <clamor95 at gmail.com> wrote:
>> > > >
>> > > > пн, 6 лист. 2023 р. о 15:13 Peter Robinson <pbrobinson at gmail.com> пише:
>> > > > >
>> > > > > On Mon, Nov 6, 2023 at 11:58 AM Svyatoslav Ryhel <clamor95 at gmail.com> wrote:
>> > > > > >
>> > > > > > пн, 6 лист. 2023 р. о 13:46 Peter Robinson <pbrobinson at gmail.com> пише:
>> > > > > > >
>> > > > > > > Hi Svyatoslav,
>> > > > > > >
>> > > > > > > > Since the proposed PMIC patches have been accepted, I see the need
>> > > > > > > > to convert boards which I maintain to use DM drivers instead of board hacks.
>> > > > > > > >
>> > > > > > > > Svyatoslav Ryhel (5):
>> > > > > > > >   board: lg-x3: convert LG Optimus 4X and Vu to use DM PMIC
>> > > > > > > >   board: endeavoru: convert HTC One X to use DM PMIC
>> > > > > > >
>> > > > > > > Is there a reason why the two above devices don't appear to have their
>> > > > > > > .dts files in the upstream kernel?
>> > > > > > >
>> > > > > >
>> > > > > > Yes, there is a reason. Linux maintainers treat submitters as
>> > > > > > existential enemies or as dirt at least. I was trying to work with
>> > > > > > linux but I have no desire to spend any time to upstream endeavoru or
>> > > > > > lg_x3.
>> > > > >
>> > > > > The usual policy for acceptance into U-Boot is to have upstream review
>> > > > > in the kernel first.
>> > > > >
>> > > >
>> > > > May you point to a policy which clearly and explicitly states this as
>> > > > a mandatory condition?
>> > > 
>> > > There have been a number of devices rejected in the past until their
>> > > DT are upstream but I'll leave Tom, who I've explicitly added on cc:,
>> > > to clarify the exact policy.
>> > 
>> > Well, here is where it's tricky. I brought this up for one of the
>> > Broadcom MIPS platforms a week or two back, and Linus Walleij's point
>> > (and I'm paraphrasing) is there's not really an upstream for it to go.
>> > 
>> > What we cannot have is device tree bindings[1] that aren't upstream or
>> > worse yet conflict with the official bindings.
>> > 
>> > So the general way to resolve that is have device tree file be drop-in
>> > from the linux kernel, and what additions we must have be done via
>> > -u-boot.dtsi files. And in turn, some SoCs are better about keeping in
>> > sync with the kernel than other SoCs are.
>> > 
>> > Now, upstream being actively hostile to dts files, especially for older
>> > platforms? That's unfortunate. So long as we aren't violating the rules
>> > about bindings, the intention is that we don't have device trees that
>> > are either (a) massively out of sync with the kernel[2] or (b) kept
>> > intentionally mismatched from the kernel.
>> > 
>> > -- 
>> > Tom
>> > 
>> > [1]: There are both examples like binman that Simon is working on at
>> > least but this is more exception than intentional rule.
>> > [2]: Per our other conversions, I know the tegra ones are in this
>> > unfortunate state in general
>> 
>> On the Tegra side we've been fairly lax about the device trees in
>> U-Boot, I suppose. The assumption had always been that U-Boot would load
>> an external DTB and pass it to the kernel on boot, so keeping them both
>> in sync was never a high priority.
>> 
>> U-Boot does only a very tiny amount of what Linux does, so dropping in
>> the kernel DTB always seemed a bit overkill.
>> 
>> In either case, if this is problematic, it's something that I could take
>> a look at. Again, it's expected that the device trees are different, for
>> historical reasons, but I'd be surprised if they actually conflict with
>> one another. U-Boot's DTB was always supposed to be a subset of the
>> Linux DTB.
>
>So, the issue with U-Boot and kernel device trees being out of sync is
>that we then can't support the model of "just pass the current DT to the
>OS". This in general is good to support because it means that even if a
>given platform isn't formally SystemReady IR certified it's still likely
>to be functional.
>
>The most strict rule is that you can't have bindings in U-Boot that
>conflict with the kernel, or should be in the kernel but aren't, and so
>on.
>

So you say that U-Boot should support only components which have linux driver? May you clarify?