Re: [PATCH v11] i2c: designware: defer probe if child GpioInt controllers are not bound

On Wed, 15 Jul 2026 13:47:01 +0200, Hardik Prakash
<[email protected]> said:
> I2C controllers may have child devices with GpioInt resources that
> depend on GPIO controllers being fully initialized. If the I2C
> controller probes and enumerates children before the referenced GPIO
> controller has completed probe, GPIO interrupts may not be properly
> configured, leading to device failures.
>
> On Lenovo Yoga 7 14AGP11, the WACF2200 touchscreen (child of
> AMDI0010:02) has a GpioInt resource pointing to GPIO 157 on the
> pinctrl-amd controller (AMDI0030:00). When i2c-designware probes
> AMDI0010:02 before pinctrl-amd finishes initializing, I2C transactions
> fail with lost arbitration errors:
>
>   0.285952  amd_gpio_probe: registering gpiochip  <- GPIO chip visible
>   0.287121  amd_gpio_probe: requesting parent IRQ <- probe still running
>   0.301454  AMDI0010:02 dw_i2c_plat_probe: start  <- races here
>   2.348157  lost arbitration
>
> Add a dependency check that walks ACPI child devices and defers probe
> until any referenced GPIO controller is bound.
>
> Fixes: 3812a9e84265 ("pinctrl-amd: enable IRQ for WACF2200 touchscreen on Lenovo Yoga 7 14AGP11")
> Suggested-by: Mario Limonciello <[email protected]>
> Signed-off-by: Hardik Prakash <[email protected]>
> Assisted-by: Claude:claude-sonnet-5
> Assisted-by: DeepSeek:deepseek-v4-pro
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=221494
> ---
>  drivers/i2c/busses/i2c-designware-platdrv.c | 80 +++++++++++++++++++++
>  1 file changed, 80 insertions(+)
> v10 -> v11:
> - Replaced custom gpio_controller_ref list with gpio_device_find_by_fwnode(),
>   as suggested by Andy, dropping the linked list and dedup logic (~60 lines)
> - Moved resource-skip explanation from commit message into a code comment
> - Fixed device_is_bound() to check gpio_device_to_device(gdev)->parent
>   rather than the gpio_device's own internal class device, which never
>   has a driver bound to it
>

Please include the entire changelog in every new iteration. I believe I gave
my Ack for this and now it's gone. I have no idea why because there's neither
a complete changelog nor links to previous versions.

Bart