Merge tag 'gpio-v4.18-3' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio

Pull GPIO fix from Linus Walleij:
 "This is a single fix affecting X86 ACPI, and as such pretty important.

  It is going to stable as well and have all the high-notch x86 platform
  developers agreeing on it"

* tag 'gpio-v4.18-3' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio:
  gpiolib-acpi: make sure we trigger edge events at least once on boot

1 files changed, 55 insertions, 1 deletions

diff --git a/drivers/gpio/gpiolib-acpi.c b/drivers/gpio/gpiolib-acpi.c
index e2232cbcec8b..addd9fecc198 100644
--- a/drivers/gpio/gpiolib-acpi.c
+++ b/drivers/gpio/gpiolib-acpi.c
@@ -25,6 +25,7 @@
 
 struct acpi_gpio_event {
 	struct list_head node;
+	struct list_head initial_sync_list;
 	acpi_handle handle;
 	unsigned int pin;
 	unsigned int irq;
@@ -50,6 +51,9 @@ struct acpi_gpio_chip {
 	struct list_head events;
 };
 
+static LIST_HEAD(acpi_gpio_initial_sync_list);
+static DEFINE_MUTEX(acpi_gpio_initial_sync_list_lock);
+
 static int acpi_gpiochip_find(struct gpio_chip *gc, void *data)
 {
 	if (!gc->parent)
@@ -85,6 +89,21 @@ static struct gpio_desc *acpi_get_gpiod(char *path, int pin)
 	return gpiochip_get_desc(chip, pin);
 }
 
+static void acpi_gpio_add_to_initial_sync_list(struct acpi_gpio_event *event)
+{
+	mutex_lock(&acpi_gpio_initial_sync_list_lock);
+	list_add(&event->initial_sync_list, &acpi_gpio_initial_sync_list);
+	mutex_unlock(&acpi_gpio_initial_sync_list_lock);
+}
+
+static void acpi_gpio_del_from_initial_sync_list(struct acpi_gpio_event *event)
+{
+	mutex_lock(&acpi_gpio_initial_sync_list_lock);
+	if (!list_empty(&event->initial_sync_list))
+		list_del_init(&event->initial_sync_list);
+	mutex_unlock(&acpi_gpio_initial_sync_list_lock);
+}
+
 static irqreturn_t acpi_gpio_irq_handler(int irq, void *data)
 {
 	struct acpi_gpio_event *event = data;
@@ -136,7 +155,7 @@ static acpi_status acpi_gpiochip_request_interrupt(struct acpi_resource *ares,
 	irq_handler_t handler = NULL;
 	struct gpio_desc *desc;
 	unsigned long irqflags;
-	int ret, pin, irq;
+	int ret, pin, irq, value;
 
 	if (!acpi_gpio_get_irq_resource(ares, &agpio))
 		return AE_OK;
@@ -167,6 +186,8 @@ static acpi_status acpi_gpiochip_request_interrupt(struct acpi_resource *ares,
 
 	gpiod_direction_input(desc);
 
+	value = gpiod_get_value(desc);
+
 	ret = gpiochip_lock_as_irq(chip, pin);
 	if (ret) {
 		dev_err(chip->parent, "Failed to lock GPIO as interrupt\n");
@@ -208,6 +229,7 @@ static acpi_status acpi_gpiochip_request_interrupt(struct acpi_resource *ares,
 	event->irq = irq;
 	event->pin = pin;
 	event->desc = desc;
+	INIT_LIST_HEAD(&event->initial_sync_list);
 
 	ret = request_threaded_irq(event->irq, NULL, handler, irqflags,
 				   "ACPI:Event", event);
@@ -222,6 +244,18 @@ static acpi_status acpi_gpiochip_request_interrupt(struct acpi_resource *ares,
 		enable_irq_wake(irq);
 
 	list_add_tail(&event->node, &acpi_gpio->events);
+
+	/*
+	 * Make sure we trigger the initial state of the IRQ when using RISING
+	 * or FALLING.  Note we run the handlers on late_init, the AML code
+	 * may refer to OperationRegions from other (builtin) drivers which
+	 * may be probed after us.
+	 */
+	if (handler == acpi_gpio_irq_handler &&
+	    (((irqflags & IRQF_TRIGGER_RISING) && value == 1) ||
+	     ((irqflags & IRQF_TRIGGER_FALLING) && value == 0)))
+		acpi_gpio_add_to_initial_sync_list(event);
+
 	return AE_OK;
 
 fail_free_event:
@@ -294,6 +328,8 @@ void acpi_gpiochip_free_interrupts(struct gpio_chip *chip)
 	list_for_each_entry_safe_reverse(event, ep, &acpi_gpio->events, node) {
 		struct gpio_desc *desc;
 
+		acpi_gpio_del_from_initial_sync_list(event);
+
 		if (irqd_is_wakeup_set(irq_get_irq_data(event->irq)))
 			disable_irq_wake(event->irq);
 
@@ -1158,3 +1194,21 @@ bool acpi_can_fallback_to_crs(struct acpi_device *adev, const char *con_id)
 
 	return con_id == NULL;
 }
+
+/* Sync the initial state of handlers after all builtin drivers have probed */
+static int acpi_gpio_initial_sync(void)
+{
+	struct acpi_gpio_event *event, *ep;
+
+	mutex_lock(&acpi_gpio_initial_sync_list_lock);
+	list_for_each_entry_safe(event, ep, &acpi_gpio_initial_sync_list,
+				 initial_sync_list) {
+		acpi_evaluate_object(event->handle, NULL, NULL, NULL);
+		list_del_init(&event->initial_sync_list);
+	}
+	mutex_unlock(&acpi_gpio_initial_sync_list_lock);
+
+	return 0;
+}
+/* We must use _sync so that this runs after the first deferred_probe run */
+late_initcall_sync(acpi_gpio_initial_sync);