ACPI: thermal_lib: Add functions returning temperature in deci-Kelvin

Because the ACPI thermal driver generally operates temperature values
in deci-Kelvin, it needs the library functions returning temperature
for various trip point types to use deci-Kelvin too.

To address that, arrange the ACPI thermal library code in three levels
of functions where the high-level ones will return temperature in
milli-Celsius, as needed by the thermal core and the majority of
thermal drivers, the mid-level ones will return temperature in
deci-Kelvin and will be called internally by the corresponding high-
level functions, and all of the mid-level functions will call the same
low-level one, acpi_trip_temp(), to actually evaluate ACPI objects to
retrieve themperature values from the platform firmware.

Going forward, this will allow the ACPI thermal driver to use the
mid-level functions to provide temperature values needed by it, so as
to reduce code duplication related to evaluating trip temperature ACPI
control methods.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/acpi/thermal_lib.c

@@ -3,8 +3,8 @@
  * Copyright 2023 Linaro Limited
  * Copyright 2023 Intel Corporation
  *
- * Library routines for populating a generic thermal trip point structure
- * with data obtained by evaluating a specific object in the ACPI Namespace.
+ * Library routines for retrieving trip point temperature values from the
+ * platform firmware via ACPI.
  */
 #include <linux/acpi.h>
 #include <linux/units.h>
@@ -17,11 +17,11 @@
  * firmware. Any values out of these boundaries may be considered
  * bogus and we can assume the firmware has no data to provide.
  */
-#define TEMP_MIN_DECIK	2180
-#define TEMP_MAX_DECIK	4480
+#define TEMP_MIN_DECIK	2180ULL
+#define TEMP_MAX_DECIK	4480ULL
 
-static int thermal_acpi_trip_temp(struct acpi_device *adev, char *obj_name,
-				  int *ret_temp)
+static int acpi_trip_temp(struct acpi_device *adev, char *obj_name,
+			  int *ret_temp)
 {
 	unsigned long long temp;
 	acpi_status status;
@@ -33,7 +33,7 @@ static int thermal_acpi_trip_temp(struct acpi_device *adev, char *obj_name,
 	}
 
 	if (temp >= TEMP_MIN_DECIK && temp <= TEMP_MAX_DECIK) {
-		*ret_temp = deci_kelvin_to_millicelsius(temp);
+		*ret_temp = temp;
 	} else {
 		acpi_handle_debug(adev->handle, "%s result %llu out of range\n",
 				  obj_name, temp);
@@ -43,6 +43,44 @@ static int thermal_acpi_trip_temp(struct acpi_device *adev, char *obj_name,
 	return 0;
 }
 
+int acpi_active_trip_temp(struct acpi_device *adev, int id, int *ret_temp)
+{
+	char obj_name[] = {'_', 'A', 'C', '0' + id, '\0'};
+
+	if (id < 0 || id > 9)
+		return -EINVAL;
+
+	return acpi_trip_temp(adev, obj_name, ret_temp);
+}
+
+int acpi_passive_trip_temp(struct acpi_device *adev, int *ret_temp)
+{
+	return acpi_trip_temp(adev, "_PSV", ret_temp);
+}
+
+int acpi_hot_trip_temp(struct acpi_device *adev, int *ret_temp)
+{
+	return acpi_trip_temp(adev, "_HOT", ret_temp);
+}
+
+int acpi_critical_trip_temp(struct acpi_device *adev, int *ret_temp)
+{
+	return acpi_trip_temp(adev, "_CRT", ret_temp);
+}
+
+static int thermal_temp(int error, int temp_decik, int *ret_temp)
+{
+	if (error)
+		return error;
+
+	if (temp_decik == THERMAL_TEMP_INVALID)
+		*ret_temp = THERMAL_TEMP_INVALID;
+	else
+		*ret_temp = deci_kelvin_to_millicelsius(temp_decik);
+
+	return 0;
+}
+
 /**
  * thermal_acpi_active_trip_temp - Retrieve active trip point temperature
  * @adev: Target thermal zone ACPI device object.
@@ -57,12 +95,10 @@ static int thermal_acpi_trip_temp(struct acpi_device *adev, char *obj_name,
  */
 int thermal_acpi_active_trip_temp(struct acpi_device *adev, int id, int *ret_temp)
 {
-	char obj_name[] = {'_', 'A', 'C', '0' + id, '\0'};
+	int temp_decik;
+	int ret = acpi_active_trip_temp(adev, id, &temp_decik);
 
-	if (id < 0 || id > 9)
-		return -EINVAL;
-
-	return thermal_acpi_trip_temp(adev, obj_name, ret_temp);
+	return thermal_temp(ret, temp_decik, ret_temp);
 }
 EXPORT_SYMBOL_GPL(thermal_acpi_active_trip_temp);
 
@@ -78,7 +114,10 @@ EXPORT_SYMBOL_GPL(thermal_acpi_active_trip_temp);
  */
 int thermal_acpi_passive_trip_temp(struct acpi_device *adev, int *ret_temp)
 {
-	return thermal_acpi_trip_temp(adev, "_PSV", ret_temp);
+	int temp_decik;
+	int ret = acpi_passive_trip_temp(adev, &temp_decik);
+
+	return thermal_temp(ret, temp_decik, ret_temp);
 }
 EXPORT_SYMBOL_GPL(thermal_acpi_passive_trip_temp);
 
@@ -95,7 +134,10 @@ EXPORT_SYMBOL_GPL(thermal_acpi_passive_trip_temp);
  */
 int thermal_acpi_hot_trip_temp(struct acpi_device *adev, int *ret_temp)
 {
-	return thermal_acpi_trip_temp(adev, "_HOT", ret_temp);
+	int temp_decik;
+	int ret = acpi_hot_trip_temp(adev, &temp_decik);
+
+	return thermal_temp(ret, temp_decik, ret_temp);
 }
 EXPORT_SYMBOL_GPL(thermal_acpi_hot_trip_temp);
 
@@ -111,6 +153,9 @@ EXPORT_SYMBOL_GPL(thermal_acpi_hot_trip_temp);
  */
 int thermal_acpi_critical_trip_temp(struct acpi_device *adev, int *ret_temp)
 {
-	return thermal_acpi_trip_temp(adev, "_CRT", ret_temp);
+	int temp_decik;
+	int ret = acpi_critical_trip_temp(adev, &temp_decik);
+
+	return thermal_temp(ret, temp_decik, ret_temp);
 }
 EXPORT_SYMBOL_GPL(thermal_acpi_critical_trip_temp);