xref: /linux/drivers/thermal/thermal_trip.c (revision 06a130e42a5bfc84795464bff023bff4c16f58c5)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *  Copyright (C) 2008 Intel Corp
4  *  Copyright (C) 2008 Zhang Rui <rui.zhang@intel.com>
5  *  Copyright (C) 2008 Sujith Thomas <sujith.thomas@intel.com>
6  *  Copyright 2022 Linaro Limited
7  *
8  * Thermal trips handling
9  */
10 #include "thermal_core.h"
11 
12 static const char *trip_type_names[] = {
13 	[THERMAL_TRIP_ACTIVE] = "active",
14 	[THERMAL_TRIP_PASSIVE] = "passive",
15 	[THERMAL_TRIP_HOT] = "hot",
16 	[THERMAL_TRIP_CRITICAL] = "critical",
17 };
18 
19 const char *thermal_trip_type_name(enum thermal_trip_type trip_type)
20 {
21 	if (trip_type < THERMAL_TRIP_ACTIVE || trip_type > THERMAL_TRIP_CRITICAL)
22 		return "unknown";
23 
24 	return trip_type_names[trip_type];
25 }
26 
27 int for_each_thermal_trip(struct thermal_zone_device *tz,
28 			  int (*cb)(struct thermal_trip *, void *),
29 			  void *data)
30 {
31 	struct thermal_trip_desc *td;
32 	int ret;
33 
34 	for_each_trip_desc(tz, td) {
35 		ret = cb(&td->trip, data);
36 		if (ret)
37 			return ret;
38 	}
39 
40 	return 0;
41 }
42 EXPORT_SYMBOL_GPL(for_each_thermal_trip);
43 
44 int thermal_zone_for_each_trip(struct thermal_zone_device *tz,
45 			       int (*cb)(struct thermal_trip *, void *),
46 			       void *data)
47 {
48 	int ret;
49 
50 	mutex_lock(&tz->lock);
51 	ret = for_each_thermal_trip(tz, cb, data);
52 	mutex_unlock(&tz->lock);
53 
54 	return ret;
55 }
56 EXPORT_SYMBOL_GPL(thermal_zone_for_each_trip);
57 
58 void thermal_zone_set_trips(struct thermal_zone_device *tz, int low, int high)
59 {
60 	int ret;
61 
62 	lockdep_assert_held(&tz->lock);
63 
64 	if (!tz->ops.set_trips)
65 		return;
66 
67 	/* No need to change trip points */
68 	if (tz->prev_low_trip == low && tz->prev_high_trip == high)
69 		return;
70 
71 	tz->prev_low_trip = low;
72 	tz->prev_high_trip = high;
73 
74 	dev_dbg(&tz->device,
75 		"new temperature boundaries: %d < x < %d\n", low, high);
76 
77 	/*
78 	 * Set a temperature window. When this window is left the driver
79 	 * must inform the thermal core via thermal_zone_device_update.
80 	 */
81 	ret = tz->ops.set_trips(tz, low, high);
82 	if (ret)
83 		dev_err(&tz->device, "Failed to set trips: %d\n", ret);
84 }
85 
86 int thermal_zone_trip_id(const struct thermal_zone_device *tz,
87 			 const struct thermal_trip *trip)
88 {
89 	/*
90 	 * Assume the trip to be located within the bounds of the thermal
91 	 * zone's trips[] table.
92 	 */
93 	return trip_to_trip_desc(trip) - tz->trips;
94 }
95 
96 void thermal_zone_set_trip_hyst(struct thermal_zone_device *tz,
97 				struct thermal_trip *trip, int hyst)
98 {
99 	WRITE_ONCE(trip->hysteresis, hyst);
100 	thermal_notify_tz_trip_change(tz, trip);
101 }
102 
103 void thermal_zone_set_trip_temp(struct thermal_zone_device *tz,
104 				struct thermal_trip *trip, int temp)
105 {
106 	if (trip->temperature == temp)
107 		return;
108 
109 	WRITE_ONCE(trip->temperature, temp);
110 	thermal_notify_tz_trip_change(tz, trip);
111 
112 	if (temp == THERMAL_TEMP_INVALID) {
113 		struct thermal_trip_desc *td = trip_to_trip_desc(trip);
114 
115 		if (tz->temperature >= td->threshold) {
116 			/*
117 			 * The trip has been crossed on the way up, so some
118 			 * adjustments are needed to compensate for the lack
119 			 * of it going forward.
120 			 */
121 			if (trip->type == THERMAL_TRIP_PASSIVE) {
122 				tz->passive--;
123 				WARN_ON_ONCE(tz->passive < 0);
124 			}
125 			thermal_zone_trip_down(tz, trip);
126 		}
127 		/*
128 		 * Invalidate the threshold to avoid triggering a spurious
129 		 * trip crossing notification when the trip becomes valid.
130 		 */
131 		td->threshold = INT_MAX;
132 	}
133 }
134 EXPORT_SYMBOL_GPL(thermal_zone_set_trip_temp);
135