[PATCH v12] i2c: designware: defer probe if child GpioInt controllers are not bound

[PATCH v12] i2c: designware: defer probe if child GpioInt controllers are not bound

[Hardik Prakash]

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 <mario.limonciello@amd.com>
Suggested-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Signed-off-by: Hardik Prakash <hardikprakash.official@gmail.com>
Assisted-by: Claude:claude-sonnet-5
Assisted-by: DeepSeek:deepseek-v4-pro
Link: https://bugzilla.kernel.org/show_bug.cgi?id=221494
---
v11 -> v12:
- Move gdev declaration to point of use with gpio_device_find_by_fwnode()
  call (Andy Shevchenko)
- Extract acpi_get_handle() return into acpi_status variable rather than
  inline in ACPI_FAILURE() (Andy Shevchenko)
- Use guard(device)(...) instead of scoped_guard(device, ...) {} for a
  single following statement (Andy Shevchenko)
- Use LIST_HEAD(res_list) instead of separate declaration + INIT_LIST_HEAD()
  (Andy Shevchenko)
- Check acpi_dev_get_resources() error before freeing the resource list,
  restoring the check-then-free ordering that had regressed in v11
  (Andy Shevchenko)
- Split ACPI_COMPANION(dev) assignment onto its own line rather than at
  declaration (Andy Shevchenko)

v10 -> v11:
- Replaced custom gpio_controller_ref list and dedup logic with
  gpio_device_find_by_fwnode() (Suggested-by: Andy Shevchenko)
- 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 is
  registered on the synthetic "gpio" bus and never has a driver bound to it

v9 -> v10:
- Use acpi_gpio_get_irq_resource() instead of open-coding GPIO resource
  type checks, eliminating duplication with gpiolib-acpi (Andy Shevchenko)
- Simplify string_source guard to a single string_length check, confirmed
  sufficient via ACPICA parser in drivers/acpi/acpica/rsutils.c
  (Andy Shevchenko)
- acpi_dev_get_resources() on single line, free only on success path
  (Andy Shevchenko)
- Reversed xmas tree ordering for variable declarations (Andy Shevchenko)
- Removed useless int ret = 0 assignment (Andy Shevchenko)
- acpi_dev_for_each_child() on single line (Andy Shevchenko)
- Use guard(device)(gpio_dev) pattern to avoid uninitialized variable
  warning and deduplicate the !gpio_dev check (Andy Shevchenko)

v8 -> v9:
- Sent as a 2-patch series: revert of the broken v8 patch, plus a
  corrected resubmission
- Use acpi_gpio_get_irq_resource() instead of open-coding GPIO resource
  type checks, eliminating duplication with gpiolib-acpi (Andy Shevchenko)
- Remove gpio_dep_ctx wrapper struct, pass list_head * directly (Andy Shevchenko)
- Add const to gpio_controller_ref.path (Andy Shevchenko)
- Add NULL check for resource_source.string_ptr to fix a crash on hardware
  where GPIO resources have no named controller (Reported-by: Nathan
  Chancellor, Reported-by: Chaitanya Kumar Borah)
- Use acpi_dev_get_resources() return value properly (Andy Shevchenko)
- Fix all error paths to call free_gpio_controller_list() (Andy Shevchenko)
- Change guard to #if defined(CONFIG_ACPI) && defined(CONFIG_GPIOLIB)
- Remove erroneous put_device() calls -- acpi_get_first_physical_node()
  returns a borrowed pointer with no refcount increment
- Use LIST_HEAD() macro, split adev declaration and assignment (Andy Shevchenko)
- scoped_guard single statement without braces (Andy Shevchenko)
- Remove misused Reported-by/Closes tags (Andy Shevchenko)

v7 -> v8:
- Add revert of the earlier pinctrl-amd DMI quirk (patch 1 of the original
  v1-v7 series), confirmed unnecessary once probe ordering is fixed
  (Mario Limonciello)
- Collect Acked-by (Bartosz Golaszewski) and Reviewed-by (Mario Limonciello)

v6 -> v7:
- Fix unused 'ret' variable in check_child_gpioint() (kernel test robot)
- Replace BugLink: with Link: (Bartosz Golaszewski)
- Add Reported-by and Closes tags for kernel test robot warning

v5 -> v6:
- Replace DMI-specific deferral with a generic GpioInt dependency check
  walking ACPI child devices (Suggested-by: Mario Limonciello)

v4 -> v5:
- Add blank line before #include <linux/acpi.h> (Bartosz Golaszewski)
- Use scoped_guard(device, gpio_dev) (Bartosz Golaszewski)

v3 -> v4:
- Rebase onto Linus Walleij's tree (the original patch 1 already there)
- Use --base so series is correctly 1/1 (Andy Shevchenko)

v2 -> v3:
- Fix variable declaration style (Andy Shevchenko)
- Add BugLink tag (Andy Shevchenko)
- CC AMD engineers (Andy Shevchenko)

v1 -> v2:
- Replace custom HID/UID lookup with acpi_dev_get_first_match_dev()
- Use device_is_bound() under device_lock() with explanatory comments
- Add Assisted-by tags per coding-assistants.rst

Note: this patch was originally part of a 2-patch series (v1-v7) whose
first patch was a DMI-specific pinctrl-amd IRQ quirk; that patch was
merged separately into Linus Walleij's tree at v1 and later reverted at
v8 once this patch made the manual IRQ restoration unnecessary.

 drivers/i2c/busses/i2c-designware-platdrv.c | 31 ++++++++++-----------
 1 file changed, 15 insertions(+), 16 deletions(-)

diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c
index 597aa9706364..a35a9cfb4432 100644
--- a/drivers/i2c/busses/i2c-designware-platdrv.c
+++ b/drivers/i2c/busses/i2c-designware-platdrv.c
@@ -141,11 +141,11 @@ static int i2c_dw_probe_lock_support(struct dw_i2c_dev *dev)
  */
 static int check_gpioint_resource(struct acpi_resource *ares, void *data)
 {
-	struct gpio_device *gdev __free(gpio_device_put) = NULL;
 	struct acpi_resource_gpio *agpio;
 	struct acpi_device *gpio_adev;
 	struct device *gpio_dev;
 	acpi_handle handle;
+	acpi_status status;
 
 	if (!acpi_gpio_get_irq_resource(ares, &agpio))
 		return 1; /* not a GpioInt resource, skip */
@@ -153,47 +153,46 @@ static int check_gpioint_resource(struct acpi_resource *ares, void *data)
 	if (!agpio->resource_source.string_length)
 		return 1; /* no named controller, skip */
 
-	if (ACPI_FAILURE(acpi_get_handle(NULL, agpio->resource_source.string_ptr, &handle)))
+	status = acpi_get_handle(NULL, agpio->resource_source.string_ptr, &handle);
+	if (ACPI_FAILURE(status))
 		return 1;
 
 	gpio_adev = acpi_fetch_acpi_dev(handle);
 	if (!gpio_adev)
 		return 1;
 
-	gdev = gpio_device_find_by_fwnode(acpi_fwnode_handle(gpio_adev));
+	struct gpio_device *gdev __free(gpio_device_put) =
+		gpio_device_find_by_fwnode(acpi_fwnode_handle(gpio_adev));
 	if (!gdev)
 		return -EPROBE_DEFER; /* controller not registered yet: abort walk */
 
 	gpio_dev = gpio_device_to_device(gdev)->parent;
-	scoped_guard(device, gpio_dev) {
-		if (!device_is_bound(gpio_dev))
-			return -EPROBE_DEFER; /* controller not bound yet: abort walk */
-	}
+	guard(device)(gpio_dev);
+	if (!device_is_bound(gpio_dev))
+		return -EPROBE_DEFER; /* controller not bound yet: abort walk */
 
 	return 1; /* bound, skip adding to resource list, continue walk */
 }
 
 static int check_child_gpioint(struct acpi_device *adev, void *data)
 {
-	struct list_head res_list;
+	LIST_HEAD(res_list);
 	int ret;
 
-	INIT_LIST_HEAD(&res_list);
 	ret = acpi_dev_get_resources(adev, &res_list, check_gpioint_resource, NULL);
+	if (ret < 0)
+		return ret;
+
 	acpi_dev_free_resource_list(&res_list);
 
-	/*
-	 * ret is a nonnegative resource count on success, which must not
-	 * be mistaken for a nonzero "stop iteration" signal by
-	 * acpi_dev_for_each_child(); only forward genuine errors.
-	 */
-	return ret < 0 ? ret : 0;
+	return 0;
 }
 
 static int i2c_dw_check_gpio_dependencies(struct device *dev)
 {
-	struct acpi_device *adev = ACPI_COMPANION(dev);
+	struct acpi_device *adev;
 
+	adev = ACPI_COMPANION(dev);
 	if (!adev)
 		return 0;
 

base-commit: 58717b2a1365d06c8c64b72aa948541b53fe31eb
prerequisite-patch-id: 2bedab9881d6b5b467c71fd4881d859e58269b9e
-- 
2.54.0

Re: [PATCH v12] i2c: designware: defer probe if child GpioInt controllers are not bound

[Bartosz Golaszewski]

On Thu, 16 Jul 2026 13:30:55 +0200, Hardik Prakash
<hardikprakash.official@gmail.com> 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 <mario.limonciello@amd.com>
> Suggested-by: Andy Shevchenko <andriy.shevchenko@intel.com>
> Signed-off-by: Hardik Prakash <hardikprakash.official@gmail.com>
> Assisted-by: Claude:claude-sonnet-5
> Assisted-by: DeepSeek:deepseek-v4-pro
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=221494
> ---

Looks good to me.

Acked-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>

Re: [PATCH v12] i2c: designware: defer probe if child GpioInt controllers are not bound

[Andy Shevchenko]

On Thu, Jul 16, 2026 at 07:10:47AM -0700, Bartosz Golaszewski wrote:
> On Thu, 16 Jul 2026 13:30:55 +0200, Hardik Prakash
> <hardikprakash.official@gmail.com> 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 <mario.limonciello@amd.com>
> > Suggested-by: Andy Shevchenko <andriy.shevchenko@intel.com>
> > Signed-off-by: Hardik Prakash <hardikprakash.official@gmail.com>
> > Assisted-by: Claude:claude-sonnet-5
> > Assisted-by: DeepSeek:deepseek-v4-pro
> > Link: https://bugzilla.kernel.org/show_bug.cgi?id=221494
> > ---
> 
> Looks good to me.
> 
> Acked-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>

But this is wrong. It's a patch over v11 (basically it's a diff v11..v12).

Please, Hardik, be careful on what you are sending.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v12] i2c: designware: defer probe if child GpioInt controllers are not bound

[Andy Shevchenko]

On Thu, Jul 16, 2026 at 05:00:55PM +0530, Hardik Prakash wrote:
> 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.

It's utterly wrong patch. Actually this whole saga shows how AI wastes
more time than gains a productivity.

...

>  	gpio_dev = gpio_device_to_device(gdev)->parent;
> -	scoped_guard(device, gpio_dev) {
> -		if (!device_is_bound(gpio_dev))
> -			return -EPROBE_DEFER; /* controller not bound yet: abort walk */
> -	}

> +	guard(device)(gpio_dev);

When use guard()(), make sure it has a blank lines before and after, so it's
visible as a separate entity.

> +	if (!device_is_bound(gpio_dev))
> +		return -EPROBE_DEFER; /* controller not bound yet: abort walk */
>  

...

So, make sure v13 is a real patch.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v12] i2c: designware: defer probe if child GpioInt controllers are not bound

[Hardik Prakash]

On Fri, 17 Jul 2026, Andy Shevchenko wrote:
> It's utterly wrong patch. Actually this whole saga shows how AI wastes
> more time than gains a productivity.
> ...
> So, make sure v13 is a real patch.

I am sorry for the bad patch. I will take some time to ensure all of
the feedback from v10, v11, v12 is properly incorporated and that v13
is a proper patch.

On Fri, 17 Jul 2026, Andy Shevchenko wrote:
> But this is wrong. It's a patch over v11 (basically it's a diff v11..v12).

For the next patch, should I carry the Ack over, given the underlying
content didn't change?

Thanks,
Hardik

On Fri, 17 Jul 2026 at 00:25, Andy Shevchenko
<andriy.shevchenko@intel.com> wrote:
>
> On Thu, Jul 16, 2026 at 05:00:55PM +0530, Hardik Prakash wrote:
> > 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.
>
> It's utterly wrong patch. Actually this whole saga shows how AI wastes
> more time than gains a productivity.
>
> ...
>
> >       gpio_dev = gpio_device_to_device(gdev)->parent;
> > -     scoped_guard(device, gpio_dev) {
> > -             if (!device_is_bound(gpio_dev))
> > -                     return -EPROBE_DEFER; /* controller not bound yet: abort walk */
> > -     }
>
> > +     guard(device)(gpio_dev);
>
> When use guard()(), make sure it has a blank lines before and after, so it's
> visible as a separate entity.
>
> > +     if (!device_is_bound(gpio_dev))
> > +             return -EPROBE_DEFER; /* controller not bound yet: abort walk */
> >
>
> ...
>
> So, make sure v13 is a real patch.
>
> --
> With Best Regards,
> Andy Shevchenko
>
>

Re: [PATCH v12] i2c: designware: defer probe if child GpioInt controllers are not bound

[Andy Shevchenko]

On Fri, Jul 17, 2026 at 10:18:33AM +0530, Hardik Prakash wrote:
> On Fri, 17 Jul 2026, Andy Shevchenko wrote:
> > It's utterly wrong patch. Actually this whole saga shows how AI wastes
> > more time than gains a productivity.
> > ...
> > So, make sure v13 is a real patch.
> 
> I am sorry for the bad patch. I will take some time to ensure all of
> the feedback from v10, v11, v12 is properly incorporated and that v13
> is a proper patch.
> 
> On Fri, 17 Jul 2026, Andy Shevchenko wrote:
> > But this is wrong. It's a patch over v11 (basically it's a diff v11..v12).
> 
> For the next patch, should I carry the Ack over, given the underlying
> content didn't change?

I think due to this mistake you need to reset the tags. Let people
review it again (and explain in the changelog why that happens).

> On Fri, 17 Jul 2026 at 00:25, Andy Shevchenko
> <andriy.shevchenko@intel.com> wrote:
> > On Thu, Jul 16, 2026 at 05:00:55PM +0530, Hardik Prakash wrote:

> > So, make sure v13 is a real patch.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v12] i2c: designware: defer probe if child GpioInt controllers are not bound

[Bartosz Golaszewski]

On Thu, 16 Jul 2026 20:50:24 +0200, Andy Shevchenko
<andriy.shevchenko@intel.com> said:
> On Thu, Jul 16, 2026 at 07:10:47AM -0700, Bartosz Golaszewski wrote:
>> On Thu, 16 Jul 2026 13:30:55 +0200, Hardik Prakash
>> <hardikprakash.official@gmail.com> 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 <mario.limonciello@amd.com>
>> > Suggested-by: Andy Shevchenko <andriy.shevchenko@intel.com>
>> > Signed-off-by: Hardik Prakash <hardikprakash.official@gmail.com>
>> > Assisted-by: Claude:claude-sonnet-5
>> > Assisted-by: DeepSeek:deepseek-v4-pro
>> > Link: https://bugzilla.kernel.org/show_bug.cgi?id=221494
>> > ---
>>
>> Looks good to me.
>>
>> Acked-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
>
> But this is wrong. It's a patch over v11 (basically it's a diff v11..v12).
>

Hanging my head in shame as I admit I've barely glanced over the diff that
looked much smaller now. Will pay more attention next time.

Bart