[PATCH] pinctrl: amd: Add an LPS0 check() callback

[Mario Limonciello <superm1@xxxxxxxxxx>]

From: Mario Limonciello <mario.limonciello@xxxxxxx>

During suspend the pinctrl_amd driver disables the interrupts for
any GPIOs that are not marked as wake sources.

This however does not prevent them from changing the wake status
bit during suspend, it just stops the system from waking.

If the system wakes from hardware sleep for another reason (such
as plugging in the AC adapter) this wake bits might be active.

This could potentially cause problems with going back to hardware
sleep.  Add an extra debugging message when PM debugging is enabled
to help identify if this is happening.

Link: https://gitlab.freedesktop.org/drm/amd/-/issues/3929
Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx>
---
 drivers/pinctrl/pinctrl-amd.c | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/drivers/pinctrl/pinctrl-amd.c b/drivers/pinctrl/pinctrl-amd.c
index 1d7fdcdec4c85..5b4376b05eafb 100644
--- a/drivers/pinctrl/pinctrl-amd.c
+++ b/drivers/pinctrl/pinctrl-amd.c
@@ -37,6 +37,8 @@
 #include "pinctrl-utils.h"
 #include "pinctrl-amd.h"
 
+static struct amd_gpio *pinctrl_dev;
+
 static int amd_gpio_get_direction(struct gpio_chip *gc, unsigned offset)
 {
 	unsigned long flags;
@@ -909,6 +911,29 @@ static bool amd_gpio_should_save(struct amd_gpio *gpio_dev, unsigned int pin)
 	return false;
 }
 
+static void amd_gpio_check_pending(void)
+{
+	struct amd_gpio *gpio_dev = pinctrl_dev;
+	struct pinctrl_desc *desc = gpio_dev->pctrl->desc;
+	int i;
+
+	if (!pm_debug_messages_on)
+		return;
+
+	for (i = 0; i < desc->npins; i++) {
+		int pin = desc->pins[i].number;
+		u32 tmp;
+
+		tmp = readl(gpio_dev->base + pin * 4);
+		if (tmp & PIN_IRQ_PENDING)
+			pm_pr_dbg("%s: GPIO %d is active: 0x%x.\n", __func__, pin, tmp);
+	}
+}
+
+static struct acpi_s2idle_dev_ops pinctrl_amd_s2idle_dev_ops = {
+	.check = amd_gpio_check_pending,
+};
+
 static int amd_gpio_suspend_hibernate_common(struct device *dev, bool is_suspend)
 {
 	struct amd_gpio *gpio_dev = dev_get_drvdata(dev);
@@ -942,6 +967,7 @@ static int amd_gpio_suspend_hibernate_common(struct device *dev, bool is_suspend
 
 static int amd_gpio_suspend(struct device *dev)
 {
+	pinctrl_dev = dev_get_drvdata(dev);
 	return amd_gpio_suspend_hibernate_common(dev, true);
 }
 
@@ -1182,6 +1208,10 @@ static int amd_gpio_probe(struct platform_device *pdev)
 	platform_set_drvdata(pdev, gpio_dev);
 	acpi_register_wakeup_handler(gpio_dev->irq, amd_gpio_check_wake, gpio_dev);
 
+	ret = acpi_register_lps0_dev(&pinctrl_amd_s2idle_dev_ops);
+	if (ret)
+		return ret;
+
 	dev_dbg(&pdev->dev, "amd gpio driver loaded\n");
 	return ret;
 
@@ -1199,6 +1229,7 @@ static void amd_gpio_remove(struct platform_device *pdev)
 
 	gpiochip_remove(&gpio_dev->gc);
 	acpi_unregister_wakeup_handler(amd_gpio_check_wake, gpio_dev);
+	acpi_unregister_lps0_dev(&pinctrl_amd_s2idle_dev_ops);
 }
 
 #ifdef CONFIG_ACPI
-- 
2.43.0