linux-kernel - Re: [RFC PATCH v2 0/2] fw

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Message-ID: <CAGETcx-Yxtkdfytsota3AciS6M9UeOaKSRtaHfH5pm60KWVmJA@mail.gmail.com>
Date: Tue, 9 Apr 2024 18:06:33 -0700
From: Saravana Kannan <saravanak@...gle.com>
To: Herve Codina <herve.codina@...tlin.com>
Cc: Geert Uytterhoeven <geert+renesas@...der.be>, Rob Herring <robh@...nel.org>, kernel-team@...roid.com, 
	linux-kernel@...r.kernel.org, imx@...ts.linux.dev, 
	linux-arm-kernel@...ts.infradead.org, linux-i2c@...r.kernel.org, 
	devicetree@...r.kernel.org, linux-spi@...r.kernel.org, 
	linux-acpi@...r.kernel.org, Luca Ceresoli <luca.ceresoli@...tlin.com>, 
	Thomas Petazzoni <thomas.petazzoni@...tlin.com>
Subject: Re: [RFC PATCH v2 0/2] fw_devlink overlay fix

On Tue, Apr 9, 2024 at 6:02 AM Herve Codina <herve.codina@...tlin.com> wrote:
>
> Hi Saravana,
>
> +CC Luca and Thomas
>
> On Mon,  8 Apr 2024 22:37:01 -0700
> Saravana Kannan <saravanak@...gle.com> wrote:
>
> > Don't bother reviewing this patch. It needs to be tested and possibly
> > refactored first.
> >
> > Geert and Herve,
> >
> > This patch serious should hopefully fix both of your use cases
> > [1][2][3]. Can you please check to make sure the device links created
> > to/from the overlay devices are to/from the right ones?
> >
> > I've only compile tested it. If I made some obvious mistake, feel free
> > to fix it and give it a shot.
> >
> > Cc: Rob Herring <robh@...nel.org>
> >
> > [1] - https://lore.kernel.org/lkml/CAMuHMdXEnSD4rRJ-o90x4OprUacN_rJgyo8x6=9F9rZ+-KzjOg@mail.gmail.com/
> > [2] - https://lore.kernel.org/all/20240221095137.616d2aaa@bootlin.com/
> > [3] - https://lore.kernel.org/lkml/20240312151835.29ef62a0@bootlin.com/
> >
>
> I tested your patches.
>
> Concerning my use cases, they fix the issue described in
>   https://lore.kernel.org/all/20240221095137.616d2aaa@bootlin.com/

I went back and looked at the example. I'm not even sure I understand
that example. In that example at the link above, are you saying
without any changes to upstream reg_dock_sys_3v3 was listing it's
supplier as i2c5 instead of tca6424_dock_1? Why wasn't Geert's
existing changes in of_i2c_notify not sufficient? Looking at it, it
does:
rd->dn->fwnode.flags &= ~FWNODE_FLAG_NOT_DEVICE;

Which should clear the flag for tca6424_dock_1. Can you help me
understand why it's not getting cleared?

> But not the one described in
>   https://lore.kernel.org/lkml/20240312151835.29ef62a0@bootlin.com/
> A link is still present between the i2c@600 and the PCI device.
> instead of the i2c@600 and the pci-ep-bus.

What do you mean by PCI device here? You say the same thing in the
link, but I don't understand what you mean. Can you clarify what
exactly gets added by the overlay? Please use the fwnode name in all
the descriptions, even when talking about device links. That should
help avoid the confusion.

Also, if you can show what the target node of the overlay looks like,
that'd help too.

> Adding the patch clearing the FWNODE_FLAG_NOT_DEVICE in device_add() available
> at [1] on top of your patches fixes the link issue.
> With this additional patch applied, the link is present between the i2c@600
> and the pci-ep-bus.

I know the problem with this patch series. But to fix it properly, I
need to understand the root of the overlay node in your examples and
the target it's applied to.

-Saravana

>
> [1] https://lore.kernel.org/lkml/20240220111044.133776-2-herve.codina@bootlin.com/
>
> Best regards,
> Hervé