Merge branch 'thermal-core'

Merge thermal core changes for 6.7-rc1:

 - Use trip pointers in thermal governors and in the related part of
   the thermal core (Rafael Wysocki).

 - Avoid updating trip points when the thermal zone temperature falls
   into a trip point's hysteresis range (ícolas F. R. A. Prado).

* thermal-core:
  thermal: ACPI: Include the right header file
  thermal: core: Don't update trip points inside the hysteresis range
  thermal: core: Pass trip pointer to governor throttle callback
  thermal: gov_step_wise: Fold update_passive_instance() into its caller
  thermal: gov_power_allocator: Use trip pointers instead of trip indices
  thermal: gov_fair_share: Rearrange get_trip_level()
  thermal: trip: Define for_each_trip() macro
  thermal: trip: Simplify computing trip indices

10 files changed, 150 insertions, 169 deletions

diff --git a/drivers/thermal/gov_bang_bang.c b/drivers/thermal/gov_bang_bang.c
index 49cdfaa3a92793..6ddf0accdc98f9 100644
--- a/drivers/thermal/gov_bang_bang.c
+++ b/drivers/thermal/gov_bang_bang.c
@@ -13,9 +13,10 @@
 
 #include "thermal_core.h"
 
-static int thermal_zone_trip_update(struct thermal_zone_device *tz, int trip_index)
+static int thermal_zone_trip_update(struct thermal_zone_device *tz,
+				    const struct thermal_trip *trip)
 {
-	const struct thermal_trip *trip = &tz->trips[trip_index];
+	int trip_index = thermal_zone_trip_id(tz, trip);
 	struct thermal_instance *instance;
 
 	if (!trip->hysteresis)
@@ -89,7 +90,8 @@ static int thermal_zone_trip_update(struct thermal_zone_device *tz, int trip_ind
  *     (trip_temp - hyst) so that the fan gets turned off again.
  *
  */
-static int bang_bang_control(struct thermal_zone_device *tz, int trip)
+static int bang_bang_control(struct thermal_zone_device *tz,
+			     const struct thermal_trip *trip)
 {
 	struct thermal_instance *instance;
 	int ret;
diff --git a/drivers/thermal/gov_fair_share.c b/drivers/thermal/gov_fair_share.c
index 2abeb8979f5002..538abb7de4e2b1 100644
--- a/drivers/thermal/gov_fair_share.c
+++ b/drivers/thermal/gov_fair_share.c
@@ -15,29 +15,27 @@
 
 #include "thermal_core.h"
 
-/**
- * get_trip_level: - obtains the current trip level for a zone
- * @tz:		thermal zone device
- */
 static int get_trip_level(struct thermal_zone_device *tz)
 {
-	struct thermal_trip trip;
-	int count;
+	const struct thermal_trip *trip, *level_trip = NULL;
+	int trip_level;
 
-	for (count = 0; count < tz->num_trips; count++) {
-		__thermal_zone_get_trip(tz, count, &trip);
-		if (tz->temperature < trip.temperature)
+	for_each_trip(tz, trip) {
+		if (trip->temperature >= tz->temperature)
 			break;
+
+		level_trip = trip;
 	}
 
-	/*
-	 * count > 0 only if temperature is greater than first trip
-	 * point, in which case, trip_point = count - 1
-	 */
-	if (count > 0)
-		trace_thermal_zone_trip(tz, count - 1, trip.type);
+	/*  Bail out if the temperature is not greater than any trips. */
+	if (!level_trip)
+		return 0;
+
+	trip_level = thermal_zone_trip_id(tz, level_trip);
+
+	trace_thermal_zone_trip(tz, trip_level, level_trip->type);
 
-	return count;
+	return trip_level;
 }
 
 static long get_target_state(struct thermal_zone_device *tz,
@@ -49,7 +47,7 @@ static long get_target_state(struct thermal_zone_device *tz,
 /**
  * fair_share_throttle - throttles devices associated with the given zone
  * @tz: thermal_zone_device
- * @trip_index: trip point index
+ * @trip: trip point
  *
  * Throttling Logic: This uses three parameters to calculate the new
  * throttle state of the cooling devices associated with the given zone.
@@ -65,9 +63,9 @@ static long get_target_state(struct thermal_zone_device *tz,
  *	(Heavily assumes the trip points are in ascending order)
  * new_state of cooling device = P3 * P2 * P1
  */
-static int fair_share_throttle(struct thermal_zone_device *tz, int trip_index)
+static int fair_share_throttle(struct thermal_zone_device *tz,
+			       const struct thermal_trip *trip)
 {
-	const struct thermal_trip *trip = &tz->trips[trip_index];
 	struct thermal_instance *instance;
 	int total_weight = 0;
 	int total_instance = 0;
diff --git a/drivers/thermal/gov_power_allocator.c b/drivers/thermal/gov_power_allocator.c
index 1faf55446ba239..83d4f451b1a97a 100644
--- a/drivers/thermal/gov_power_allocator.c
+++ b/drivers/thermal/gov_power_allocator.c
@@ -16,8 +16,6 @@
 
 #include "thermal_core.h"
 
-#define INVALID_TRIP -1
-
 #define FRAC_BITS 10
 #define int_to_frac(x) ((x) << FRAC_BITS)
 #define frac_to_int(x) ((x) >> FRAC_BITS)
@@ -55,23 +53,23 @@ static inline s64 div_frac(s64 x, s64 y)
  * @err_integral:	accumulated error in the PID controller.
  * @prev_err:	error in the previous iteration of the PID controller.
  *		Used to calculate the derivative term.
+ * @sustainable_power:	Sustainable power (heat) that this thermal zone can
+ *			dissipate
  * @trip_switch_on:	first passive trip point of the thermal zone.  The
  *			governor switches on when this trip point is crossed.
  *			If the thermal zone only has one passive trip point,
- *			@trip_switch_on should be INVALID_TRIP.
+ *			@trip_switch_on should be NULL.
  * @trip_max_desired_temperature:	last passive trip point of the thermal
  *					zone.  The temperature we are
  *					controlling for.
- * @sustainable_power:	Sustainable power (heat) that this thermal zone can
- *			dissipate
  */
 struct power_allocator_params {
 	bool allocated_tzp;
 	s64 err_integral;
 	s32 prev_err;
-	int trip_switch_on;
-	int trip_max_desired_temperature;
 	u32 sustainable_power;
+	const struct thermal_trip *trip_switch_on;
+	const struct thermal_trip *trip_max_desired_temperature;
 };
 
 /**
@@ -90,14 +88,12 @@ static u32 estimate_sustainable_power(struct thermal_zone_device *tz)
 	u32 sustainable_power = 0;
 	struct thermal_instance *instance;
 	struct power_allocator_params *params = tz->governor_data;
-	const struct thermal_trip *trip_max_desired_temperature =
-			&tz->trips[params->trip_max_desired_temperature];
 
 	list_for_each_entry(instance, &tz->thermal_instances, tz_node) {
 		struct thermal_cooling_device *cdev = instance->cdev;
 		u32 min_power;
 
-		if (instance->trip != trip_max_desired_temperature)
+		if (instance->trip != params->trip_max_desired_temperature)
 			continue;
 
 		if (!cdev_is_power_actor(cdev))
@@ -116,24 +112,22 @@ static u32 estimate_sustainable_power(struct thermal_zone_device *tz)
  * estimate_pid_constants() - Estimate the constants for the PID controller
  * @tz:		thermal zone for which to estimate the constants
  * @sustainable_power:	sustainable power for the thermal zone
- * @trip_switch_on:	trip point number for the switch on temperature
+ * @trip_switch_on:	trip point for the switch on temperature
  * @control_temp:	target temperature for the power allocator governor
  *
  * This function is used to update the estimation of the PID
  * controller constants in struct thermal_zone_parameters.
  */
 static void estimate_pid_constants(struct thermal_zone_device *tz,
-				   u32 sustainable_power, int trip_switch_on,
+				   u32 sustainable_power,
+				   const struct thermal_trip *trip_switch_on,
 				   int control_temp)
 {
-	struct thermal_trip trip;
 	u32 temperature_threshold = control_temp;
-	int ret;
 	s32 k_i;
 
-	ret = __thermal_zone_get_trip(tz, trip_switch_on, &trip);
-	if (!ret)
-		temperature_threshold -= trip.temperature;
+	if (trip_switch_on)
+		temperature_threshold -= trip_switch_on->temperature;
 
 	/*
 	 * estimate_pid_constants() tries to find appropriate default
@@ -386,7 +380,7 @@ static int allocate_power(struct thermal_zone_device *tz,
 	struct thermal_instance *instance;
 	struct power_allocator_params *params = tz->governor_data;
 	const struct thermal_trip *trip_max_desired_temperature =
-			&tz->trips[params->trip_max_desired_temperature];
+					params->trip_max_desired_temperature;
 	u32 *req_power, *max_power, *granted_power, *extra_actor_power;
 	u32 *weighted_req_power;
 	u32 total_req_power, max_allocatable_power, total_weighted_req_power;
@@ -496,7 +490,7 @@ static int allocate_power(struct thermal_zone_device *tz,
 }
 
 /**
- * get_governor_trips() - get the number of the two trip points that are key for this governor
+ * get_governor_trips() - get the two trip points that are key for this governor
  * @tz:	thermal zone to operate on
  * @params:	pointer to private data for this governor
  *
@@ -513,46 +507,36 @@ static int allocate_power(struct thermal_zone_device *tz,
 static void get_governor_trips(struct thermal_zone_device *tz,
 			       struct power_allocator_params *params)
 {
-	int i, last_active, last_passive;
-	bool found_first_passive;
-
-	found_first_passive = false;
-	last_active = INVALID_TRIP;
-	last_passive = INVALID_TRIP;
-
-	for (i = 0; i < tz->num_trips; i++) {
-		struct thermal_trip trip;
-		int ret;
-
-		ret = __thermal_zone_get_trip(tz, i, &trip);
-		if (ret) {
-			dev_warn(&tz->device,
-				 "Failed to get trip point %d type: %d\n", i,
-				 ret);
-			continue;
-		}
-
-		if (trip.type == THERMAL_TRIP_PASSIVE) {
-			if (!found_first_passive) {
-				params->trip_switch_on = i;
-				found_first_passive = true;
-			} else  {
-				last_passive = i;
+	const struct thermal_trip *first_passive = NULL;
+	const struct thermal_trip *last_passive = NULL;
+	const struct thermal_trip *last_active = NULL;
+	const struct thermal_trip *trip;
+
+	for_each_trip(tz, trip) {
+		switch (trip->type) {
+		case THERMAL_TRIP_PASSIVE:
+			if (!first_passive) {
+				first_passive = trip;
+				break;
 			}
-		} else if (trip.type == THERMAL_TRIP_ACTIVE) {
-			last_active = i;
-		} else {
+			last_passive = trip;
+			break;
+		case THERMAL_TRIP_ACTIVE:
+			last_active = trip;
+			break;
+		default:
 			break;
 		}
 	}
 
-	if (last_passive != INVALID_TRIP) {
+	if (last_passive) {
+		params->trip_switch_on = first_passive;
 		params->trip_max_desired_temperature = last_passive;
-	} else if (found_first_passive) {
-		params->trip_max_desired_temperature = params->trip_switch_on;
-		params->trip_switch_on = INVALID_TRIP;
+	} else if (first_passive) {
+		params->trip_switch_on = NULL;
+		params->trip_max_desired_temperature = first_passive;
 	} else {
-		params->trip_switch_on = INVALID_TRIP;
+		params->trip_switch_on = NULL;
 		params->trip_max_desired_temperature = last_active;
 	}
 }
@@ -567,14 +551,12 @@ static void allow_maximum_power(struct thermal_zone_device *tz, bool update)
 {
 	struct thermal_instance *instance;
 	struct power_allocator_params *params = tz->governor_data;
-	const struct thermal_trip *trip_max_desired_temperature =
-			&tz->trips[params->trip_max_desired_temperature];
 	u32 req_power;
 
 	list_for_each_entry(instance, &tz->thermal_instances, tz_node) {
 		struct thermal_cooling_device *cdev = instance->cdev;
 
-		if ((instance->trip != trip_max_desired_temperature) ||
+		if (instance->trip != params->trip_max_desired_temperature ||
 		    (!cdev_is_power_actor(instance->cdev)))
 			continue;
 
@@ -636,7 +618,6 @@ static int power_allocator_bind(struct thermal_zone_device *tz)
 {
 	int ret;
 	struct power_allocator_params *params;
-	struct thermal_trip trip;
 
 	ret = check_power_actors(tz);
 	if (ret)
@@ -661,13 +642,11 @@ static int power_allocator_bind(struct thermal_zone_device *tz)
 
 	get_governor_trips(tz, params);
 
-	if (tz->num_trips > 0) {
-		ret = __thermal_zone_get_trip(tz, params->trip_max_desired_temperature,
-					      &trip);
-		if (!ret)
-			estimate_pid_constants(tz, tz->tzp->sustainable_power,
-					       params->trip_switch_on,
-					       trip.temperature);
+	if (params->trip_max_desired_temperature) {
+		int temp = params->trip_max_desired_temperature->temperature;
+
+		estimate_pid_constants(tz, tz->tzp->sustainable_power,
+				       params->trip_switch_on, temp);
 	}
 
 	reset_pid_controller(params);
@@ -697,11 +676,10 @@ static void power_allocator_unbind(struct thermal_zone_device *tz)
 	tz->governor_data = NULL;
 }
 
-static int power_allocator_throttle(struct thermal_zone_device *tz, int trip_id)
+static int power_allocator_throttle(struct thermal_zone_device *tz,
+				    const struct thermal_trip *trip)
 {
 	struct power_allocator_params *params = tz->governor_data;
-	struct thermal_trip trip;
-	int ret;
 	bool update;
 
 	lockdep_assert_held(&tz->lock);
@@ -710,12 +688,12 @@ static int power_allocator_throttle(struct thermal_zone_device *tz, int trip_id)
 	 * We get called for every trip point but we only need to do
 	 * our calculations once
 	 */
-	if (trip_id != params->trip_max_desired_temperature)
+	if (trip != params->trip_max_desired_temperature)
 		return 0;
 
-	ret = __thermal_zone_get_trip(tz, params->trip_switch_on, &trip);
-	if (!ret && (tz->temperature < trip.temperature)) {
-		update = (tz->last_temperature >= trip.temperature);
+	trip = params->trip_switch_on;
+	if (trip && tz->temperature < trip->temperature) {
+		update = tz->last_temperature >= trip->temperature;
 		tz->passive = 0;
 		reset_pid_controller(params);
 		allow_maximum_power(tz, update);
@@ -724,14 +702,7 @@ static int power_allocator_throttle(struct thermal_zone_device *tz, int trip_id)
 
 	tz->passive = 1;
 
-	ret = __thermal_zone_get_trip(tz, params->trip_max_desired_temperature, &trip);
-	if (ret) {
-		dev_warn(&tz->device, "Failed to get the maximum desired temperature: %d\n",
-			 ret);
-		return ret;
-	}
-
-	return allocate_power(tz, trip.temperature);
+	return allocate_power(tz, params->trip_max_desired_temperature->temperature);
 }
 
 static struct thermal_governor thermal_gov_power_allocator = {
diff --git a/drivers/thermal/gov_step_wise.c b/drivers/thermal/gov_step_wise.c
index 849dc1ec8d27c8..5436aa58d41ec7 100644
--- a/drivers/thermal/gov_step_wise.c
+++ b/drivers/thermal/gov_step_wise.c
@@ -68,26 +68,16 @@ static unsigned long get_target_state(struct thermal_instance *instance,
 	return next_target;
 }
 
-static void update_passive_instance(struct thermal_zone_device *tz,
-				enum thermal_trip_type type, int value)
+static void thermal_zone_trip_update(struct thermal_zone_device *tz,
+				     const struct thermal_trip *trip)
 {
-	/*
-	 * If value is +1, activate a passive instance.
-	 * If value is -1, deactivate a passive instance.
-	 */
-	if (type == THERMAL_TRIP_PASSIVE)
-		tz->passive += value;
-}
-
-static void thermal_zone_trip_update(struct thermal_zone_device *tz, int trip_id)
-{
-	const struct thermal_trip *trip = &tz->trips[trip_id];
+	int trip_id = thermal_zone_trip_id(tz, trip);
 	enum thermal_trend trend;
 	struct thermal_instance *instance;
 	bool throttle = false;
 	int old_target;
 
-	trend = get_tz_trend(tz, trip_id);
+	trend = get_tz_trend(tz, trip);
 
 	if (tz->temperature >= trip->temperature) {
 		throttle = true;
@@ -109,14 +99,17 @@ static void thermal_zone_trip_update(struct thermal_zone_device *tz, int trip_id
 		if (instance->initialized && old_target == instance->target)
 			continue;
 
-		/* Activate a passive thermal instance */
 		if (old_target == THERMAL_NO_TARGET &&
-			instance->target != THERMAL_NO_TARGET)
-			update_passive_instance(tz, trip->type, 1);
-		/* Deactivate a passive thermal instance */
-		else if (old_target != THERMAL_NO_TARGET &&
-			instance->target == THERMAL_NO_TARGET)
-			update_passive_instance(tz, trip->type, -1);
+		    instance->target != THERMAL_NO_TARGET) {
+			/* Activate a passive thermal instance */
+			if (trip->type == THERMAL_TRIP_PASSIVE)
+				tz->passive++;
+		} else if (old_target != THERMAL_NO_TARGET &&
+			   instance->target == THERMAL_NO_TARGET) {
+			/* Deactivate a passive thermal instance */
+			if (trip->type == THERMAL_TRIP_PASSIVE)
+				tz->passive--;
+		}
 
 		instance->initialized = true;
 		mutex_lock(&instance->cdev->lock);
@@ -128,7 +121,7 @@ static void thermal_zone_trip_update(struct thermal_zone_device *tz, int trip_id
 /**
  * step_wise_throttle - throttles devices associated with the given zone
  * @tz: thermal_zone_device
- * @trip: trip point index
+ * @trip: trip point
  *
  * Throttling Logic: This uses the trend of the thermal zone to throttle.
  * If the thermal zone is 'heating up' this throttles all the cooling
@@ -136,7 +129,8 @@ static void thermal_zone_trip_update(struct thermal_zone_device *tz, int trip_id
  * step. If the zone is 'cooling down' it brings back the performance of
  * the devices by one step.
  */
-static int step_wise_throttle(struct thermal_zone_device *tz, int trip)
+static int step_wise_throttle(struct thermal_zone_device *tz,
+			      const struct thermal_trip *trip)
 {
 	struct thermal_instance *instance;
 
diff --git a/drivers/thermal/gov_user_space.c b/drivers/thermal/gov_user_space.c
index 8bc1c22aaf0380..7a1790b7e8f557 100644
--- a/drivers/thermal/gov_user_space.c
+++ b/drivers/thermal/gov_user_space.c
@@ -25,11 +25,12 @@ static int user_space_bind(struct thermal_zone_device *tz)
 /**
  * notify_user_space - Notifies user space about thermal events
  * @tz: thermal_zone_device
- * @trip: trip point index
+ * @trip: trip point
  *
  * This function notifies the user space through UEvents.
  */
-static int notify_user_space(struct thermal_zone_device *tz, int trip)
+static int notify_user_space(struct thermal_zone_device *tz,
+			     const struct thermal_trip *trip)
 {
 	char *thermal_prop[5];
 	int i;
@@ -38,7 +39,8 @@ static int notify_user_space(struct thermal_zone_device *tz, int trip)
 
 	thermal_prop[0] = kasprintf(GFP_KERNEL, "NAME=%s", tz->type);
 	thermal_prop[1] = kasprintf(GFP_KERNEL, "TEMP=%d", tz->temperature);
-	thermal_prop[2] = kasprintf(GFP_KERNEL, "TRIP=%d", trip);
+	thermal_prop[2] = kasprintf(GFP_KERNEL, "TRIP=%d",
+				    thermal_zone_trip_id(tz, trip));
 	thermal_prop[3] = kasprintf(GFP_KERNEL, "EVENT=%d", tz->notify_event);
 	thermal_prop[4] = NULL;
 	kobject_uevent_env(&tz->device.kobj, KOBJ_CHANGE, thermal_prop);
diff --git a/drivers/thermal/thermal_acpi.c b/drivers/thermal/thermal_acpi.c
index 0e5698818f69ee..43eaf0f2ff49be 100644
--- a/drivers/thermal/thermal_acpi.c
+++ b/drivers/thermal/thermal_acpi.c
@@ -8,8 +8,7 @@
  */
 #include <linux/acpi.h>
 #include <linux/units.h>
-
-#include "thermal_core.h"
+#include <linux/thermal.h>
 
 /*
  * Minimum temperature for full military grade is 218°K (-55°C) and
diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
index 2b345f25dfa498..9c17d35ccbbd8b 100644
--- a/drivers/thermal/thermal_core.c
+++ b/drivers/thermal/thermal_core.c
@@ -307,7 +307,8 @@ static void monitor_thermal_zone(struct thermal_zone_device *tz)
 		thermal_zone_device_set_polling(tz, tz->polling_delay_jiffies);
 }
 
-static void handle_non_critical_trips(struct thermal_zone_device *tz, int trip)
+static void handle_non_critical_trips(struct thermal_zone_device *tz,
+				      const struct thermal_trip *trip)
 {
 	tz->governor ? tz->governor->throttle(tz, trip) :
 		       def_governor->throttle(tz, trip);
@@ -329,44 +330,43 @@ void thermal_zone_device_critical(struct thermal_zone_device *tz)
 EXPORT_SYMBOL(thermal_zone_device_critical);
 
 static void handle_critical_trips(struct thermal_zone_device *tz,
-				  int trip, int trip_temp, enum thermal_trip_type trip_type)
+				  const struct thermal_trip *trip)
 {
 	/* If we have not crossed the trip_temp, we do not care. */
-	if (trip_temp <= 0 || tz->temperature < trip_temp)
+	if (trip->temperature <= 0 || tz->temperature < trip->temperature)
 		return;
 
-	trace_thermal_zone_trip(tz, trip, trip_type);
+	trace_thermal_zone_trip(tz, thermal_zone_trip_id(tz, trip), trip->type);
 
-	if (trip_type == THERMAL_TRIP_HOT && tz->ops->hot)
-		tz->ops->hot(tz);
-	else if (trip_type == THERMAL_TRIP_CRITICAL)
+	if (trip->type == THERMAL_TRIP_CRITICAL)
 		tz->ops->critical(tz);
+	else if (tz->ops->hot)
+		tz->ops->hot(tz);
 }
 
-static void handle_thermal_trip(struct thermal_zone_device *tz, int trip_id)
+static void handle_thermal_trip(struct thermal_zone_device *tz,
+				const struct thermal_trip *trip)
 {
-	struct thermal_trip trip;
-
-	__thermal_zone_get_trip(tz, trip_id, &trip);
-
-	if (trip.temperature == THERMAL_TEMP_INVALID)
+	if (trip->temperature == THERMAL_TEMP_INVALID)
 		return;
 
 	if (tz->last_temperature != THERMAL_TEMP_INVALID) {
-		if (tz->last_temperature < trip.temperature &&
-		    tz->temperature >= trip.temperature)
-			thermal_notify_tz_trip_up(tz->id, trip_id,
+		if (tz->last_temperature < trip->temperature &&
+		    tz->temperature >= trip->temperature)
+			thermal_notify_tz_trip_up(tz->id,
+						  thermal_zone_trip_id(tz, trip),
 						  tz->temperature);
-		if (tz->last_temperature >= trip.temperature &&
-		    tz->temperature < (trip.temperature - trip.hysteresis))
-			thermal_notify_tz_trip_down(tz->id, trip_id,
+		if (tz->last_temperature >= trip->temperature &&
+		    tz->temperature < trip->temperature - trip->hysteresis)
+			thermal_notify_tz_trip_down(tz->id,
+						    thermal_zone_trip_id(tz, trip),
 						    tz->temperature);
 	}
 
-	if (trip.type == THERMAL_TRIP_CRITICAL || trip.type == THERMAL_TRIP_HOT)
-		handle_critical_trips(tz, trip_id, trip.temperature, trip.type);
+	if (trip->type == THERMAL_TRIP_CRITICAL || trip->type == THERMAL_TRIP_HOT)
+		handle_critical_trips(tz, trip);
 	else
-		handle_non_critical_trips(tz, trip_id);
+		handle_non_critical_trips(tz, trip);
 }
 
 static void update_temperature(struct thermal_zone_device *tz)
@@ -403,7 +403,7 @@ static void thermal_zone_device_init(struct thermal_zone_device *tz)
 void __thermal_zone_device_update(struct thermal_zone_device *tz,
 				  enum thermal_notify_event event)
 {
-	int count;
+	const struct thermal_trip *trip;
 
 	if (atomic_read(&in_suspend))
 		return;
@@ -422,8 +422,8 @@ void __thermal_zone_device_update(struct thermal_zone_device *tz,
 
 	tz->notify_event = event;
 
-	for (count = 0; count < tz->num_trips; count++)
-		handle_thermal_trip(tz, count);
+	for_each_trip(tz, trip)
+		handle_thermal_trip(tz, trip);
 
 	monitor_thermal_zone(tz);
 }
diff --git a/drivers/thermal/thermal_core.h b/drivers/thermal/thermal_core.h
index 024e82ebf5920f..0a3b3ec5120ba7 100644
--- a/drivers/thermal/thermal_core.h
+++ b/drivers/thermal/thermal_core.h
@@ -70,7 +70,7 @@ static inline bool cdev_is_power_actor(struct thermal_cooling_device *cdev)
 void thermal_cdev_update(struct thermal_cooling_device *);
 void __thermal_cdev_update(struct thermal_cooling_device *cdev);
 
-int get_tz_trend(struct thermal_zone_device *tz, int trip_index);
+int get_tz_trend(struct thermal_zone_device *tz, const struct thermal_trip *trip);
 
 struct thermal_instance *
 get_thermal_instance(struct thermal_zone_device *tz,
@@ -116,6 +116,9 @@ void __thermal_zone_device_update(struct thermal_zone_device *tz,
 				  enum thermal_notify_event event);
 
 /* Helpers */
+#define for_each_trip(__tz, __trip)	\
+	for (__trip = __tz->trips; __trip - __tz->trips < __tz->num_trips; __trip++)
+
 void __thermal_zone_set_trips(struct thermal_zone_device *tz);
 int __thermal_zone_get_trip(struct thermal_zone_device *tz, int trip_id,
 			    struct thermal_trip *trip);
diff --git a/drivers/thermal/thermal_helpers.c b/drivers/thermal/thermal_helpers.c
index c1d0af73c85d6f..69e8ea4aa908bd 100644
--- a/drivers/thermal/thermal_helpers.c
+++ b/drivers/thermal/thermal_helpers.c
@@ -22,9 +22,8 @@
 #include "thermal_core.h"
 #include "thermal_trace.h"
 
-int get_tz_trend(struct thermal_zone_device *tz, int trip_index)
+int get_tz_trend(struct thermal_zone_device *tz, const struct thermal_trip *trip)
 {
-	struct thermal_trip *trip = tz->trips ? &tz->trips[trip_index] : NULL;
 	enum thermal_trend trend;
 
 	if (tz->emul_temperature || !tz->ops->get_trend ||
diff --git a/drivers/thermal/thermal_trip.c b/drivers/thermal/thermal_trip.c
index 80f3cdb2f30ee8..e42456442c68e0 100644
--- a/drivers/thermal/thermal_trip.c
+++ b/drivers/thermal/thermal_trip.c
@@ -13,10 +13,11 @@ int for_each_thermal_trip(struct thermal_zone_device *tz,
 			  int (*cb)(struct thermal_trip *, void *),
 			  void *data)
 {
-	int i, ret;
+	struct thermal_trip *trip;
+	int ret;
 
-	for (i = 0; i < tz->num_trips; i++) {
-		ret = cb(&tz->trips[i], data);
+	for_each_trip(tz, trip) {
+		ret = cb(trip, data);
 		if (ret)
 			return ret;
 	}
@@ -64,6 +65,7 @@ void __thermal_zone_set_trips(struct thermal_zone_device *tz)
 {
 	struct thermal_trip trip;
 	int low = -INT_MAX, high = INT_MAX;
+	bool same_trip = false;
 	int i, ret;
 
 	lockdep_assert_held(&tz->lock);
@@ -72,6 +74,7 @@ void __thermal_zone_set_trips(struct thermal_zone_device *tz)
 		return;
 
 	for (i = 0; i < tz->num_trips; i++) {
+		bool low_set = false;
 		int trip_low;
 
 		ret = __thermal_zone_get_trip(tz, i , &trip);
@@ -80,18 +83,31 @@ void __thermal_zone_set_trips(struct thermal_zone_device *tz)
 
 		trip_low = trip.temperature - trip.hysteresis;
 
-		if (trip_low < tz->temperature && trip_low > low)
+		if (trip_low < tz->temperature && trip_low > low) {
 			low = trip_low;
+			low_set = true;
+			same_trip = false;
+		}
 
 		if (trip.temperature > tz->temperature &&
-		    trip.temperature < high)
+		    trip.temperature < high) {
 			high = trip.temperature;
+			same_trip = low_set;
+		}
 	}
 
 	/* No need to change trip points */
 	if (tz->prev_low_trip == low && tz->prev_high_trip == high)
 		return;
 
+	/*
+	 * If "high" and "low" are the same, skip the change unless this is the
+	 * first time.
+	 */
+	if (same_trip && (tz->prev_low_trip != -INT_MAX ||
+	    tz->prev_high_trip != INT_MAX))
+		return;
+
 	tz->prev_low_trip = low;
 	tz->prev_high_trip = high;
 
@@ -173,12 +189,9 @@ int thermal_zone_set_trip(struct thermal_zone_device *tz, int trip_id,
 int thermal_zone_trip_id(struct thermal_zone_device *tz,
 			 const struct thermal_trip *trip)
 {
-	int i;
-
-	for (i = 0; i < tz->num_trips; i++) {
-		if (&tz->trips[i] == trip)
-			return i;
-	}
-
-	return -ENODATA;
+	/*
+	 * Assume the trip to be located within the bounds of the thermal
+	 * zone's trips[] table.
+	 */
+	return trip - tz->trips;
 }