1 # SPDX-License-Identifier: (GPL-2.0-only OR BS 1 # SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
2 # Copyright 2020 Linaro Ltd. 2 # Copyright 2020 Linaro Ltd.
3 %YAML 1.2 3 %YAML 1.2
4 --- 4 ---
5 $id: http://devicetree.org/schemas/thermal/the 5 $id: http://devicetree.org/schemas/thermal/thermal-idle.yaml#
6 $schema: http://devicetree.org/meta-schemas/co 6 $schema: http://devicetree.org/meta-schemas/core.yaml#
7 7
8 title: Thermal idle cooling device 8 title: Thermal idle cooling device
9 9
10 maintainers: 10 maintainers:
11 - Daniel Lezcano <daniel.lezcano@linaro.org> 11 - Daniel Lezcano <daniel.lezcano@linaro.org>
12 12
13 description: | 13 description: |
14 The thermal idle cooling device allows the s 14 The thermal idle cooling device allows the system to passively
15 mitigate the temperature on the device by in 15 mitigate the temperature on the device by injecting idle cycles,
16 forcing it to cool down. 16 forcing it to cool down.
17 17
18 This binding describes the thermal idle node 18 This binding describes the thermal idle node.
19 19
20 properties: 20 properties:
21 $nodename: 21 $nodename:
22 const: thermal-idle 22 const: thermal-idle
23 description: | 23 description: |
24 A thermal-idle node describes the idle c 24 A thermal-idle node describes the idle cooling device properties to
25 cool down efficiently the attached therm 25 cool down efficiently the attached thermal zone.
26 26
27 '#cooling-cells': 27 '#cooling-cells':
28 const: 2 28 const: 2
29 description: | 29 description: |
30 Must be 2, in order to specify minimum a 30 Must be 2, in order to specify minimum and maximum cooling state used in
31 the cooling-maps reference. The first ce 31 the cooling-maps reference. The first cell is the minimum cooling state
32 and the second cell is the maximum cooli 32 and the second cell is the maximum cooling state requested.
33 33
34 duration-us: 34 duration-us:
35 description: | 35 description: |
36 The idle duration in microsecond the dev 36 The idle duration in microsecond the device should cool down.
37 37
38 exit-latency-us: 38 exit-latency-us:
39 description: | 39 description: |
40 The exit latency constraint in microseco 40 The exit latency constraint in microsecond for the injected idle state
41 for the device. It is the latency constr 41 for the device. It is the latency constraint to apply when selecting an
42 idle state from among all the present on 42 idle state from among all the present ones.
43 43
44 required: 44 required:
45 - '#cooling-cells' 45 - '#cooling-cells'
46 46
47 additionalProperties: false 47 additionalProperties: false
48 48
49 examples: 49 examples:
50 - | 50 - |
51 /{ 51 /{
52 #include <dt-bindings/thermal/thermal. 52 #include <dt-bindings/thermal/thermal.h>
53 53
54 compatible = "foo"; 54 compatible = "foo";
55 model = "foo"; 55 model = "foo";
56 #address-cells = <1>; 56 #address-cells = <1>;
57 #size-cells = <1>; 57 #size-cells = <1>;
58 58
59 // Example: Combining idle cooling dev 59 // Example: Combining idle cooling device on big CPUs with cpufreq cooling device
60 cpus { 60 cpus {
61 #address-cells = <2>; 61 #address-cells = <2>;
62 #size-cells = <0>; 62 #size-cells = <0>;
63 63
64 /* ... */ 64 /* ... */
65 65
66 cpu_b0: cpu@100 { 66 cpu_b0: cpu@100 {
67 device_type = "cpu"; 67 device_type = "cpu";
68 compatible = "arm,cortex-a72"; 68 compatible = "arm,cortex-a72";
69 reg = <0x0 0x100>; 69 reg = <0x0 0x100>;
70 enable-method = "psci"; 70 enable-method = "psci";
71 capacity-dmips-mhz = <1024>; 71 capacity-dmips-mhz = <1024>;
72 dynamic-power-coefficient = <4 72 dynamic-power-coefficient = <436>;
73 #cooling-cells = <2>; /* min f 73 #cooling-cells = <2>; /* min followed by max */
74 cpu-idle-states = <&CPU_SLEEP> 74 cpu-idle-states = <&CPU_SLEEP>, <&CLUSTER_SLEEP>;
75 cpu_b0_therm: thermal-idle { 75 cpu_b0_therm: thermal-idle {
76 #cooling-cells = <2>; 76 #cooling-cells = <2>;
77 duration-us = <10000>; 77 duration-us = <10000>;
78 exit-latency-us = <500>; 78 exit-latency-us = <500>;
79 }; 79 };
80 }; 80 };
81 81
82 cpu_b1: cpu@101 { 82 cpu_b1: cpu@101 {
83 device_type = "cpu"; 83 device_type = "cpu";
84 compatible = "arm,cortex-a72"; 84 compatible = "arm,cortex-a72";
85 reg = <0x0 0x101>; 85 reg = <0x0 0x101>;
86 enable-method = "psci"; 86 enable-method = "psci";
87 capacity-dmips-mhz = <1024>; 87 capacity-dmips-mhz = <1024>;
88 dynamic-power-coefficient = <4 88 dynamic-power-coefficient = <436>;
89 #cooling-cells = <2>; /* min f 89 #cooling-cells = <2>; /* min followed by max */
90 cpu-idle-states = <&CPU_SLEEP> 90 cpu-idle-states = <&CPU_SLEEP>, <&CLUSTER_SLEEP>;
91 cpu_b1_therm: thermal-idle { 91 cpu_b1_therm: thermal-idle {
92 #cooling-cells = <2>; 92 #cooling-cells = <2>;
93 duration-us = <10000>; 93 duration-us = <10000>;
94 exit-latency-us = <500>; 94 exit-latency-us = <500>;
95 }; 95 };
96 }; 96 };
97 97
98 /* ... */ 98 /* ... */
99 99
100 }; 100 };
101 101
102 /* ... */ 102 /* ... */
103 103
104 thermal_zones { 104 thermal_zones {
105 cpu_thermal: cpu { 105 cpu_thermal: cpu {
106 polling-delay-passive = <100>; 106 polling-delay-passive = <100>;
107 polling-delay = <1000>; 107 polling-delay = <1000>;
108 108
109 /* ... */ 109 /* ... */
110 110
111 trips { 111 trips {
112 cpu_alert0: cpu_alert0 { 112 cpu_alert0: cpu_alert0 {
113 temperature = <65000>; 113 temperature = <65000>;
114 hysteresis = <2000>; 114 hysteresis = <2000>;
115 type = "passive"; 115 type = "passive";
116 }; 116 };
117 117
118 cpu_alert1: cpu_alert1 { 118 cpu_alert1: cpu_alert1 {
119 temperature = <70000>; 119 temperature = <70000>;
120 hysteresis = <2000>; 120 hysteresis = <2000>;
121 type = "passive"; 121 type = "passive";
122 }; 122 };
123 123
124 cpu_alert2: cpu_alert2 { 124 cpu_alert2: cpu_alert2 {
125 temperature = <75000>; 125 temperature = <75000>;
126 hysteresis = <2000>; 126 hysteresis = <2000>;
127 type = "passive"; 127 type = "passive";
128 }; 128 };
129 129
130 cpu_crit: cpu_crit { 130 cpu_crit: cpu_crit {
131 temperature = <95000>; 131 temperature = <95000>;
132 hysteresis = <2000>; 132 hysteresis = <2000>;
133 type = "critical"; 133 type = "critical";
134 }; 134 };
135 }; 135 };
136 136
137 cooling-maps { 137 cooling-maps {
138 map0 { 138 map0 {
139 trip = <&cpu_alert1>; 139 trip = <&cpu_alert1>;
140 cooling-device = <&cpu 140 cooling-device = <&cpu_b0_therm 0 15 >,
141 <&cpu 141 <&cpu_b1_therm 0 15>;
142 }; 142 };
143 143
144 map1 { 144 map1 {
145 trip = <&cpu_alert2>; 145 trip = <&cpu_alert2>;
146 cooling-device = <&cpu 146 cooling-device = <&cpu_b0 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
147 <&cpu 147 <&cpu_b1 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>;
148 }; 148 };
149 }; 149 };
150 }; 150 };
151 }; 151 };
152 }; 152 };
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