[PATCH 3/3] mfd: cros_ec: Add ACPI GPE handler for LID0 devices

[Thierry Escande <thierry.escande@collabora.com>]

From: Archana Patni <archana.patni@intel.com>

This patch installs an ACPI GPE handler for LID0 ACPI device to indicate
ACPI core that this GPE should stay enabled for lid to work in suspend
to idle path.

Signed-off-by: Archana Patni <archana.patni@intel.com>
Signed-off-by: Thierry Escande <thierry.escande@collabora.com>
---
 drivers/mfd/cros_ec.c | 97 +++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 95 insertions(+), 2 deletions(-)

diff --git a/drivers/mfd/cros_ec.c b/drivers/mfd/cros_ec.c
index b8a5080..628718e 100644
--- a/drivers/mfd/cros_ec.c
+++ b/drivers/mfd/cros_ec.c
@@ -17,6 +17,9 @@
  * battery charging and regulator control, firmware update.
  */
 
+#ifdef CONFIG_ACPI
+#include <linux/acpi.h>
+#endif
 #include <linux/of_platform.h>
 #include <linux/interrupt.h>
 #include <linux/slab.h>
@@ -29,6 +32,73 @@
 #define CROS_EC_DEV_EC_INDEX 0
 #define CROS_EC_DEV_PD_INDEX 1
 
+#ifdef CONFIG_ACPI
+
+#define ACPI_LID_DEVICE      "LID0"
+
+static int ec_wake_gpe = -EINVAL;
+
+/*
+ * This handler indicates to ACPI core that this GPE should stay enabled for
+ * lid to work in suspend to idle path.
+ */
+static u32 cros_ec_gpe_handler(acpi_handle gpe_device, u32 gpe_number,
+			       void *data)
+{
+	return ACPI_INTERRUPT_HANDLED | ACPI_REENABLE_GPE;
+}
+
+/*
+ * Get ACPI GPE for LID0 device.
+ */
+static int cros_ec_get_ec_wake_gpe(struct device *dev)
+{
+	struct acpi_device *cros_acpi_dev;
+	struct acpi_device *adev;
+	acpi_handle handle;
+	acpi_status status;
+	int ret;
+
+	cros_acpi_dev = ACPI_COMPANION(dev);
+
+	if (!cros_acpi_dev || !cros_acpi_dev->parent ||
+	   !cros_acpi_dev->parent->handle)
+		return -EINVAL;
+
+	status = acpi_get_handle(cros_acpi_dev->parent->handle, ACPI_LID_DEVICE,
+				 &handle);
+	if (ACPI_FAILURE(status))
+		return -EINVAL;
+
+	ret = acpi_bus_get_device(handle, &adev);
+	if (ret)
+		return ret;
+
+	return adev->wakeup.gpe_number;
+}
+
+static int cros_ec_install_handler(struct device *dev)
+{
+	acpi_status status;
+
+	ec_wake_gpe = cros_ec_get_ec_wake_gpe(dev);
+
+	if (ec_wake_gpe < 0)
+		return ec_wake_gpe;
+
+	status = acpi_install_gpe_handler(NULL, ec_wake_gpe,
+					  ACPI_GPE_EDGE_TRIGGERED,
+					  &cros_ec_gpe_handler, NULL);
+	if (ACPI_FAILURE(status))
+		return -ENODEV;
+
+	dev_info(dev, "Initialized, GPE = 0x%x\n", ec_wake_gpe);
+
+	return 0;
+}
+
+#endif
+
 static struct cros_ec_platform ec_p = {
 	.ec_name = CROS_EC_DEV_NAME,
 	.cmd_offset = EC_CMD_PASSTHRU_OFFSET(CROS_EC_DEV_EC_INDEX),
@@ -166,6 +236,10 @@ int cros_ec_register(struct cros_ec_device *ec_dev)
 
 	dev_info(dev, "Chrome EC device registered\n");
 
+#ifdef CONFIG_ACPI
+	cros_ec_install_handler(dev);
+#endif
+
 	return 0;
 
 fail_mfd:
@@ -179,6 +253,17 @@ int cros_ec_remove(struct cros_ec_device *ec_dev)
 {
 	mfd_remove_devices(ec_dev->dev);
 
+#ifdef CONFIG_ACPI
+	if (ec_wake_gpe >= 0) {
+		acpi_status status;
+
+		status = acpi_remove_gpe_handler(NULL, ec_wake_gpe,
+						 &cros_ec_gpe_handler);
+		if (ACPI_FAILURE(status))
+			pr_err("failed to remove gpe handler\n");
+	}
+#endif
+
 	return 0;
 }
 EXPORT_SYMBOL(cros_ec_remove);
@@ -190,8 +275,16 @@ int cros_ec_suspend(struct cros_ec_device *ec_dev)
 	int ret;
 	u8 sleep_event;
 
-	sleep_event = pm_suspend_via_firmware() ? HOST_SLEEP_EVENT_S3_RESUME :
-						  HOST_SLEEP_EVENT_S0IX_RESUME;
+	if (!pm_suspend_via_firmware()) {
+		sleep_event = HOST_SLEEP_EVENT_S0IX_SUSPEND;
+#ifdef CONFIG_ACPI
+		/* Clearing the GPE status for any pending event */
+		if (ec_wake_gpe >= 0)
+			acpi_clear_gpe(NULL, ec_wake_gpe);
+#endif
+	} else {
+		sleep_event = HOST_SLEEP_EVENT_S3_SUSPEND;
+	}
 
 	ret = cros_ec_sleep_event(ec_dev, sleep_event);
 	if (ret < 0)
-- 
2.7.4