ACPI: thermal: Add Thermal fast Sampling Period (_TFP) support

Add support of "Thermal fast Sampling Period (_TFP)" for passive
cooling.

As per the ACPI specification (ACPI 6.5, Section 11.4.17 "_TFP (Thermal
fast Sampling Period)", _TFP overrides _TSP ("Thermal Sampling Period"
if both are present in a Thermal zone.
Signed-off-by: Jeff Brasen <jbrasen@nvidia.com>
Co-developed-by: Sumit Gupta <sumitg@nvidia.com>
Signed-off-by: Sumit Gupta <sumitg@nvidia.com>
[ rjw: Changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/acpi/thermal.c

@@ -92,7 +92,7 @@ struct acpi_thermal_passive {
 	struct acpi_thermal_trip trip;
 	unsigned long tc1;
 	unsigned long tc2;
-	unsigned long tsp;
+	unsigned long delay;
 };
 
 struct acpi_thermal_active {
@@ -396,11 +396,17 @@ static bool passive_trip_params_init(struct acpi_thermal *tz)
 
 	tz->trips.passive.tc2 = tmp;
 
+	status = acpi_evaluate_integer(tz->device->handle, "_TFP", NULL, &tmp);
+	if (ACPI_SUCCESS(status)) {
+		tz->trips.passive.delay = tmp;
+		return true;
+	}
+
 	status = acpi_evaluate_integer(tz->device->handle, "_TSP", NULL, &tmp);
 	if (ACPI_FAILURE(status))
 		return false;
 
-	tz->trips.passive.tsp = tmp;
+	tz->trips.passive.delay = tmp * 100;
 
 	return true;
 }
@@ -896,7 +902,7 @@ static int acpi_thermal_add(struct acpi_device *device)
 
 	acpi_trip = &tz->trips.passive.trip;
 	if (acpi_thermal_trip_valid(acpi_trip)) {
-		passive_delay = tz->trips.passive.tsp * 100;
+		passive_delay = tz->trips.passive.delay;
 
 		trip->type = THERMAL_TRIP_PASSIVE;
 		trip->temperature = acpi_thermal_temp(tz, acpi_trip->temp_dk);