[PATCH v2 1/2] acpi: battery: Query Battery charge time ("_BCT") method

[Umang Jain]

Add plumbing for querying the Battery Charge Time ("_BCT") method.
If present, set ACPI_BATTERY_BCT_PRESENT in battery flags to denote
that the method is supported in ACPI.

Signed-off-by: Umang Jain <uajain@xxxxxxxxxx>
---
 drivers/acpi/battery.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/drivers/acpi/battery.c b/drivers/acpi/battery.c
index 670853ec3a4d..a1b7a821abaf 100644
--- a/drivers/acpi/battery.c
+++ b/drivers/acpi/battery.c
@@ -76,6 +76,7 @@ MODULE_DEVICE_TABLE(acpi, battery_device_ids);
 enum {
 	ACPI_BATTERY_ALARM_PRESENT,
 	ACPI_BATTERY_XINFO_PRESENT,
+	ACPI_BATTERY_BCT_PRESENT,
 	ACPI_BATTERY_QUIRK_PERCENTAGE_CAPACITY,
 	/* On Lenovo Thinkpad models from 2010 and 2011, the power unit
 	 * switches between mWh and mAh depending on whether the system
@@ -110,6 +111,7 @@ struct acpi_battery {
 
 	struct mutex property_lock; /* Protects properties below. */
 	unsigned long update_time;
+	unsigned long long charge_time;
 	int revision;
 	int rate_now;
 	int capacity_now;
@@ -613,6 +615,10 @@ static int acpi_battery_get_state(struct acpi_battery *battery)
 	int result = 0;
 	acpi_status status = 0;
 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
+	union acpi_object arg0 = { ACPI_TYPE_INTEGER };
+	struct acpi_object_list args = { 1, &arg0 };
+
+	arg0.integer.value = 100;
 
 	lockdep_assert_held(&battery->property_lock);
 
@@ -638,6 +644,15 @@ static int acpi_battery_get_state(struct acpi_battery *battery)
 	battery->update_time = jiffies;
 	kfree(buffer.pointer);
 
+	if (test_bit(ACPI_BATTERY_BCT_PRESENT, &battery->flags)) {
+		status = acpi_evaluate_integer(battery->device->handle, "_BCT",
+					       &args, &battery->charge_time);
+	if (ACPI_FAILURE(status))
+		acpi_handle_info(battery->device->handle,
+				 "_BCT evaluation failed: %s",
+				 acpi_format_exception(status));
+	}
+
 	/* For buggy DSDTs that report negative 16-bit values for either
 	 * charging or discharging current and/or report 0 as 65536
 	 * due to bad math.
@@ -1083,6 +1098,8 @@ static int acpi_battery_update(struct acpi_battery *battery, bool resume)
 			if (result)
 				return result;
 			acpi_battery_init_alarm(battery);
+			if (acpi_has_method(battery->device->handle, "_BCT"))
+				set_bit(ACPI_BATTERY_BCT_PRESENT, &battery->flags);
 		}
 
 		result = acpi_battery_get_state(battery);
-- 
2.55.0