[PATCH] gpiolib-acpi: make sure we trigger the events at least once on boot

[Benjamin Tissoires]

The Surface 3 has its _LID state controlled by an ACPI operation region
triggered by a GPIO event:

 OperationRegion (GPOR, GeneralPurposeIo, Zero, One)
 Field (GPOR, ByteAcc, NoLock, Preserve)
 {
     Connection (
         GpioIo (Shared, PullNone, 0x0000, 0x0000, IoRestrictionNone,
             "\\_SB.GPO0", 0x00, ResourceConsumer, ,
             )
             {   // Pin list
                 0x004C
             }
     ),
     HELD,   1
 }

 Method (_E4C, 0, Serialized)  // _Exx: Edge-Triggered GPE
 {
     If ((HELD == One))
     {
         ^^LID.LIDB = One
     }
     Else
     {
         ^^LID.LIDB = Zero
         Notify (LID, 0x80) // Status Change
     }

     Notify (^^PCI0.SPI1.NTRG, One) // Device Check
 }

Currently, the state of LIDB is wrong until the user actually closes or
open the cover. We need to trigger the GPIO event once to update the
internal ACPI state.

Coincidentally, this also enables the integrated HID sensor hub which also
requires an ACPI gpio operation region to start initialization.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx>
---
 drivers/gpio/gpiolib-acpi.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/gpio/gpiolib-acpi.c b/drivers/gpio/gpiolib-acpi.c
index 2dc5258..71775a0 100644
--- a/drivers/gpio/gpiolib-acpi.c
+++ b/drivers/gpio/gpiolib-acpi.c
@@ -175,7 +175,7 @@ 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 (ares->type != ACPI_RESOURCE_TYPE_GPIO)
 		return AE_OK;
@@ -214,6 +214,8 @@ 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");
@@ -266,6 +268,15 @@ static acpi_status acpi_gpiochip_request_interrupt(struct acpi_resource *ares,
 	}
 
 	list_add_tail(&event->node, &acpi_gpio->events);
+
+	/*
+	 * Make sure we trigger the initial state of the IRQ when
+	 * using RISING or FALLING.
+	 */
+	if (((irqflags & IRQF_TRIGGER_RISING) && value == 1) ||
+	    ((irqflags & IRQF_TRIGGER_FALLING) && value == 0))
+		handler(-1, event);
+
 	return AE_OK;
 
 fail_free_event:
-- 
2.5.0

---

Now, if I am not mistaken, we could simply check the value of _LID on
resume and if it differs from the previous state, force an input_event
from the _LID. That should at least re-trigger the LID close event
(sent by the ACPI) for the next attempt.

Cheers,
Benjamin