[Patch v4 1/2] ACPI: thermal: Add Thermal fast Sampling Period (_TFP) support

[Sumit Gupta <sumitg@nvidia.com>]

From: Jeff Brasen <jbrasen@nvidia.com>

Add support of "Thermal fast Sampling Period (_TFP)" for Passive cooling.
As per [1], _TFP overrides the "Thermal Sampling Period (_TSP)" if both
are present in a Thermal zone.

[1] ACPI Specification 6.4 - section 11.4.17. _TFP (Thermal fast Sampling
    Period)"

Signed-off-by: Jeff Brasen <jbrasen@nvidia.com>
Signed-off-by: Sumit Gupta <sumitg@nvidia.com>
---
 drivers/acpi/thermal.c | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/drivers/acpi/thermal.c b/drivers/acpi/thermal.c
index 356d577689ff..e360aeebd249 100644
--- a/drivers/acpi/thermal.c
+++ b/drivers/acpi/thermal.c
@@ -90,7 +90,7 @@ struct acpi_thermal_passive {
 	struct acpi_thermal_trip trip;
 	unsigned long tc1;
 	unsigned long tc2;
-	unsigned long tsp;
+	unsigned long passive_delay;
 };
 
 struct acpi_thermal_active {
@@ -404,11 +404,16 @@ static bool passive_trip_params_init(struct acpi_thermal *tz)
 
 	tz->trips.passive.tc2 = tmp;
 
-	status = acpi_evaluate_integer(tz->device->handle, "_TSP", NULL, &tmp);
-	if (ACPI_FAILURE(status))
-		return false;
+	status = acpi_evaluate_integer(tz->device->handle, "_TFP", NULL, &tmp);
+	if (ACPI_FAILURE(status)) {
+		status = acpi_evaluate_integer(tz->device->handle, "_TSP", NULL, &tmp);
+		if (ACPI_FAILURE(status))
+			return false;
 
-	tz->trips.passive.tsp = tmp;
+		tz->trips.passive.passive_delay = tmp * 100;
+	} else {
+		tz->trips.passive.passive_delay = tmp;
+	}
 
 	return true;
 }
@@ -904,7 +909,7 @@ 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.passive_delay;
 
 		trip->type = THERMAL_TRIP_PASSIVE;
 		trip->temperature = acpi_thermal_temp(tz, acpi_trip->temp_dk);
-- 
2.17.1