Re: [PATCH v4 01/29] Revert "treewide: Fix probing of devices in DT overlays"

Kalle Niemi
2025-12-02T11:21:21Z

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On 12/2/25 11:26, Herve Codina wrote:
> Hi Kalle,
>
> On Fri, 28 Nov 2025 10:34:57 +0200
> Kalle Niemi <kaleposti@gmail.com> wrote:
>
> ...
>>>>>>>>
>>>>>>>> Hello,
>>>>>>>>
>>>>>>>> Test system testing drivers for ROHM ICs bisected this commit to cause
>>>>>>>> BD71847 drivers probe to not be called.
>>>>>>> This driver (and overlay support) is in linux-next or something out of
>>>>>>> tree on top of linux-next?
>>>>>>>
>>>>>>> Rob
>>>>>> Yes the driver is in mainline linux: /drivers/mfd/rohm-bd718x7.c
>>>>> I don't see any support to apply overlays in that driver.
>>>> Ah. Sorry for the confusion peeps. I asked Kalle to report this without
>>>> proper consideration. 100% my bad.
>>>>
>>>> While the bd718x7 drive indeed is mainline (and tested), the actual
>>>> 'glue-code' doing the overlay is part of the downstream test
>>>> infrastructure. So yes, this is not a bug in upstream kernel - this
>>>> falls in the category of an upstream change causing downstream things to
>>>> break. So, feel free to say: "Go fix your code" :)
>>>>
>>>> Now that this is sorted, if someone is still interested in helping us to
>>>> get our upstream drivers tested - the downstream piece is just taking
>>>> the compiled device-tree overlay at runtime (via bin-attribute file),
>>>> and applying it using the of_overlay_fdt_apply(). The approach is
>>>> working for our testing purposes when the device is added to I2C/SPI
>>>> node which is already enabled. However, in case where we have the I2C
>>>> disabled, and enable it in the same overlay where we add the new device
>>>> - then the new device does not get probed.
>>>>
>>>> I would be really grateful if someone had a pointer for us.
>>> Seems to be fw_devlink related. I suppose if you turn it off it works?
>>> There's info about the dependencies in sysfs or maybe debugfs. I don't
>>> remember the details, but that should help to tell you why things
>>> aren't probing.
>
> Rob reverted patches but I plan to continue my work on it.
> On my side, I need the reverted patches but I fully understand that, on
> your side, you need a working system.
>
> In order to move forward and find a solution for my next iteration, can you
> send your overlay (dtso) used in your working and non working cases?
>
> Best regards,
> Hervé

Hello Hervé,

I have attached the overlay source file: bd71847_overlay.dts

BR
Kalle

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