[PATCH v2 0/2] Fix WACF2200 touchscreen on Lenovo Yoga 7 14AGP11

[PATCH v2 0/2] Fix WACF2200 touchscreen on Lenovo Yoga 7 14AGP11

[Hardik Prakash]

The Wacom WACF2200 touchscreen on the Lenovo Yoga 7 14AGP11 (83TD) is
completely non-functional on Linux. The I2C bus (AMDI0010:02) fails with
repeated lost arbitration errors at boot before any driver can probe the
device. The touchscreen works correctly in UEFI and Windows.

Investigation using ACPI _CRS decode and Windows/Linux GPIO register
comparison identified two bugs:

1. GPIO 157 (WACF2200 GpioInt per ACPI _CRS) has INTERRUPT_ENABLE and
   INTERRUPT_MASK cleared by amd_gpio_irq_init() and never restored,
   preventing the device from signalling the driver. Windows keeps both
   bits set after initialisation.

2. i2c_designware probes AMDI0010:02 before pinctrl-amd's probe
   completes. A DMI-matched deferral is added to correctly enforce
   ordering using device_is_bound() under device_lock().

Patch 1 adds a DMI quirk in pinctrl-amd to restore GPIO 157 interrupt
bits after amd_gpio_irq_init().

Patch 2 adds a probe deferral in i2c-designware-platdrv that correctly
waits for pinctrl-amd to fully complete before AMDI0010:02 is probed,
using acpi_dev_get_first_match_dev() and acpi_get_first_physical_node()
for robust device lookup.

Both patches tested on Lenovo Yoga 7 14AGP11 (83TD), Fedora 44, kernel
7.1.0-rc2+. Touch and stylus fully functional across 4 stable reboots.

v2:
 - Patch 2: replace custom HID/UID lookup helpers with
   acpi_dev_get_first_match_dev() (Andy Shevchenko)
 - Patch 2: use acpi_get_first_physical_node() to get the platform
   device for correct device_is_bound() check
 - Patch 2: use device_is_bound() under device_lock() with explanatory
   comments (Andy Shevchenko)
 - Patch 2: fix dev_warn to use dev_name() instead of hardcoded suffix
   (Andy Shevchenko)
 - Patch 2: fix commit message (removed incorrect "existing" reference)
 - Both patches: add Assisted-by tags per coding-assistants.rst
 - Patch 1: no functional changes (Acked-by: Andy Shevchenko)

Kernel bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=221494
Related: https://bugzilla.kernel.org/show_bug.cgi?id=221454


 drivers/i2c/busses/i2c-designware-platdrv.c | 75 +++++++++++++++++++++
 drivers/pinctrl/pinctrl-amd.c               | 35 ++++++++++
 2 files changed, 110 insertions(+)

-- 
2.54.0

[PATCH 1/2] pinctrl-amd: enable IRQ for WACF2200 touchscreen on Lenovo Yoga 7 14AGP11

[Hardik Prakash]

On Lenovo Yoga 7 14AGP11 (83TD), the WACF2200 touchscreen controller
is wired via I2C2 (AMDI0010:02) with its interrupt on GPIO pin 157
(confirmed via ACPI _CRS GpioInt decode). After amd_gpio_irq_init()
clears all GPIO interrupts at boot, pin 157 is never re-enabled,
preventing the touchscreen from signalling the driver.

Windows keeps GPIO 157 INTERRUPT_ENABLE (bit 11) and INTERRUPT_MASK
(bit 12) set after initialisation. Add a DMI quirk to restore these
bits after amd_gpio_irq_init() on this hardware.

Signed-off-by: Hardik Prakash <hardikprakash.official@gmail.com>
Assisted-by: Claude:claude-sonnet-4-6
Assisted-by: GPT-Codex:gpt-5.2-codex
---
 drivers/pinctrl/pinctrl-amd.c | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/drivers/pinctrl/pinctrl-amd.c b/drivers/pinctrl/pinctrl-amd.c
index e3128b0045d22..64315b0edf2a6 100644
--- a/drivers/pinctrl/pinctrl-amd.c
+++ b/drivers/pinctrl/pinctrl-amd.c
@@ -26,6 +26,7 @@
 #include <linux/interrupt.h>
 #include <linux/bitops.h>
 #include <linux/pinctrl/pinconf.h>
+#include <linux/dmi.h>
 #include <linux/pinctrl/pinconf-generic.h>
 #include <linux/pinctrl/pinmux.h>
 #include <linux/string_choices.h>
@@ -39,6 +40,39 @@
 static struct amd_gpio *pinctrl_dev;
 #endif
 
+static const struct dmi_system_id amd_gpio_quirk_yoga7_14agp11[] = {
+	{
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "83TD"),
+			DMI_MATCH(DMI_BOARD_NAME, "LNVNB161216"),
+		},
+	},
+	{ }
+};
+
+static void amd_gpio_apply_quirks(struct amd_gpio *gpio_dev)
+{
+	const unsigned int pin = 157; /* WACF2200 GpioInt per ACPI _CRS */
+	unsigned long flags;
+	u32 reg;
+
+	if (!dmi_check_system(amd_gpio_quirk_yoga7_14agp11))
+		return;
+	if (pin >= gpio_dev->gc.ngpio)
+		return;
+
+	raw_spin_lock_irqsave(&gpio_dev->lock, flags);
+	reg = readl(gpio_dev->base + pin * 4);
+	reg |= BIT(INTERRUPT_ENABLE_OFF) | BIT(INTERRUPT_MASK_OFF);
+	writel(reg, gpio_dev->base + pin * 4);
+	raw_spin_unlock_irqrestore(&gpio_dev->lock, flags);
+
+	dev_info(&gpio_dev->pdev->dev,
+		 "Enabled IRQ for GPIO %u (Yoga 7 14AGP11 touchscreen)\n",
+		 pin);
+}
+
 static int amd_gpio_get_direction(struct gpio_chip *gc, unsigned offset)
 {
 	unsigned long flags;
@@ -1219,6 +1253,7 @@ static int amd_gpio_probe(struct platform_device *pdev)
 
 	/* Disable and mask interrupts */
 	amd_gpio_irq_init(gpio_dev);
+	amd_gpio_apply_quirks(gpio_dev);
 
 	girq = &gpio_dev->gc.irq;
 	gpio_irq_chip_set_chip(girq, &amd_gpio_irqchip);
-- 
2.54.0

[PATCH 2/2] i2c: designware: fix probe ordering for AMD GPIO on Lenovo Yoga 7 14AGP11

[Hardik Prakash]

On Lenovo Yoga 7 14AGP11 (83TD), the WACF2200 touchscreen fails with
lost arbitration errors on AMDI0010:02 at boot. The root cause is a
probe ordering issue: i2c_designware probes AMDI0010:02 before
pinctrl-amd has finished initialising, so the GPIO 157 interrupt
needed by the touchscreen is not yet enabled.

Add a DMI-matched deferral in dw_i2c_plat_probe() that uses
device_is_bound() under device_lock() to correctly wait until
pinctrl-amd's probe has fully completed. Use acpi_dev_get_first_match_dev()
for robust HID/UID-based GPIO controller lookup instead of string
name matching.

Signed-off-by: Hardik Prakash <hardikprakash.official@gmail.com>
Assisted-by: Claude:claude-sonnet-4-6
Assisted-by: GPT-Codex:gpt-5.2-codex
---
 drivers/i2c/busses/i2c-designware-platdrv.c | 75 +++++++++++++++++++++
 1 file changed, 75 insertions(+)

diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c
index 3351c4a9ef118..35fa4bcafc7ad 100644
--- a/drivers/i2c/busses/i2c-designware-platdrv.c
+++ b/drivers/i2c/busses/i2c-designware-platdrv.c
@@ -8,6 +8,7 @@
  * Copyright (C) 2007 MontaVista Software Inc.
  * Copyright (C) 2009 Provigent Ltd.
  */
+#include <linux/acpi.h>
 #include <linux/clk-provider.h>
 #include <linux/clk.h>
 #include <linux/delay.h>
@@ -86,6 +87,76 @@ static const struct dmi_system_id dw_i2c_hwmon_class_dmi[] = {
 	{ } /* terminate list */
 };
 
+static const struct dmi_system_id dw_i2c_amd_gpio_defer_dmi[] = {
+	{
+		.ident = "Lenovo Yoga 7 14AGP11",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "83TD"),
+			DMI_MATCH(DMI_BOARD_NAME, "LNVNB161216"),
+		},
+	},
+	{ } /* terminate list */
+};
+
+static bool dw_i2c_needs_amd_gpio_dep(struct device *device)
+{
+	struct acpi_device *adev = ACPI_COMPANION(device);
+
+	if (!dmi_check_system(dw_i2c_amd_gpio_defer_dmi))
+		return false;
+	if (!adev)
+		return false;
+
+	return acpi_dev_hid_uid_match(adev, "AMDI0010", "2");
+}
+
+static int dw_i2c_defer_for_amd_gpio(struct device *device)
+{
+	struct acpi_device *gpio_adev;
+	struct device *gpio_dev;
+
+	if (!dw_i2c_needs_amd_gpio_dep(device))
+		return 0;
+
+	/*
+	 * Find the AMD GPIO controller by HID/UID and get its physical
+	 * platform device. We need the platform device (not the ACPI device)
+	 * because that is what gets bound by the amd_gpio driver.
+	 */
+	gpio_adev = acpi_dev_get_first_match_dev("AMDI0030", "0", -1);
+	if (!gpio_adev)
+		return -EPROBE_DEFER;
+
+	gpio_dev = acpi_get_first_physical_node(gpio_adev);
+	acpi_dev_put(gpio_adev);
+	if (!gpio_dev)
+		return -EPROBE_DEFER;
+
+	/*
+	 * Check that amd_gpio probe has fully completed, not just that the
+	 * driver pointer is set. The driver pointer is assigned before probe
+	 * finishes, so checking it would allow i2c_designware to probe before
+	 * the GPIO IRQ quirk in amd_gpio_probe() has run.
+	 */
+	device_lock(gpio_dev);
+	if (!device_is_bound(gpio_dev)) {
+		device_unlock(gpio_dev);
+		return -EPROBE_DEFER;
+	}
+	device_unlock(gpio_dev);
+
+	/*
+	 * Create a device link so the driver core enforces probe/remove
+	 * ordering between this I2C controller and the GPIO controller.
+	 */
+	if (!device_link_add(device, gpio_dev, DL_FLAG_AUTOREMOVE_CONSUMER))
+		dev_warn(device, "failed to add device link to %s\n",
+			 dev_name(gpio_dev));
+
+	return 0;
+}
+
 static const struct i2c_dw_semaphore_callbacks i2c_dw_semaphore_cb_table[] = {
 #ifdef CONFIG_I2C_DESIGNWARE_BAYTRAIL
 	{
@@ -138,6 +209,10 @@ static int dw_i2c_plat_probe(struct platform_device *pdev)
 	struct dw_i2c_dev *dev;
 	int irq, ret;
 
+	ret = dw_i2c_defer_for_amd_gpio(device);
+	if (ret)
+		return ret;
+
 	irq = platform_get_irq_optional(pdev, 0);
 	if (irq == -ENXIO)
 		flags |= ACCESS_POLLING;
-- 
2.54.0

Re: [PATCH 1/2] pinctrl-amd: enable IRQ for WACF2200 touchscreen on Lenovo Yoga 7 14AGP11

[Linus Walleij]

On Wed, May 13, 2026 at 8:14 AM Hardik Prakash
<hardikprakash.official@gmail.com> wrote:

> On Lenovo Yoga 7 14AGP11 (83TD), the WACF2200 touchscreen controller
> is wired via I2C2 (AMDI0010:02) with its interrupt on GPIO pin 157
> (confirmed via ACPI _CRS GpioInt decode). After amd_gpio_irq_init()
> clears all GPIO interrupts at boot, pin 157 is never re-enabled,
> preventing the touchscreen from signalling the driver.
>
> Windows keeps GPIO 157 INTERRUPT_ENABLE (bit 11) and INTERRUPT_MASK
> (bit 12) set after initialisation. Add a DMI quirk to restore these
> bits after amd_gpio_irq_init() on this hardware.
>
> Signed-off-by: Hardik Prakash <hardikprakash.official@gmail.com>
> Assisted-by: Claude:claude-sonnet-4-6
> Assisted-by: GPT-Codex:gpt-5.2-codex

You forgot to carry over Andy's ACK!

I see that the only real change was the addition of the two AI tags so I
just added these to the commit already in my tree.

Yours,
Linus Walleij