Re: [PATCH v4 00/10] gpio: improve support for shared GPIOs

On Fri, Jan 9, 2026 at 3:41 PM Michael Walle [off-list ref] wrote:

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I am aware of the issue where
false-positive shared GPIOs are detected, I posted a fix for that too.
Without logs, I can't really tell if that's the case for you though.
:(

What I mean is, GPIO_SHARED is automatically selected by ARCH_QCOM (and
probably others in the future). But GPIO_SHARED_PROXY is
selectable by the user and it can be deselected. But you cannot
specifically deactivate GPIO_SHARED. So there is no way to go back
to the former hacky shared gpio handling; which might be intended :)

If so, shouldn't be GPIO_SHARED_PROXY be either y or m if GPIO_SHARED=y ?
I.e. don't allow it to be deselected.

Fair point. I'll send a patch.

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This broke my board (using the arm64 defconfig, works without
GPIO_SHARED of course). I'm seeing two issues here with my board
(arch/arm64/boot/dts/ti/k3-am67a-kontron-sa67*):

 (1) It's GPIO controller (gpio-davinci) doesn't support
     .get_direction so I'm getting ENOTSUPP during probing of the
     (some?) shared GPIOs.

Unless this board really shares GPIOs, it may be due to the
false-positives that will be fixed by this patch[1]. If you enable

Yeah this board shares an enable GPIO for two regulators
(regulator-5 and regulator-6,
arch/arm64/boot/dts/ti/k3-am67a-kontron-sa67-base.dts).

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CONFIG_DEBUG_GPIO and post the kernel log, I'll be able to tell for
sure.

See end of this mail. I've applied the mentioned patch.

Yes, I see there are indeed shared pins.

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Though thanks for bringing this to my attention as I now see there is
indeed an issue when the proxied chip doesn't support .get_direction()
as well as a duplicated check in GPIO core. I'll fix it too.

quoted

 (2) GPIO_SHARED_PROXY is default m in the defconfig, but I need the
     pins for the root filesystem medium, i.e. the SD card regulators.

I'll take care of this is you confirm, the issue persists even with patch[1].

Not sure this is still valid. Because I've just learned that
apparently, the arm64 Image shall be made smaller and thus "need
a driver for rootfs" isn't a valid reason for =y anymore.

Is a switch to disable shared GPIO management entirely via Kconfig
(depending on CONFIG_EXPERT) good enough for you?

Bart