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1 | EXYNOS EMULATION MODE |
2 | ======================== | |
3 | ||
4 | Copyright (C) 2012 Samsung Electronics | |
5 | ||
6 | Written by Jonghwa Lee <jonghwa3.lee@samsung.com> | |
7 | ||
8 | Description | |
9 | ----------- | |
10 | ||
11 | Exynos 4x12 (4212, 4412) and 5 series provide emulation mode for thermal management unit. | |
12 | Thermal emulation mode supports software debug for TMU's operation. User can set temperature | |
13 | manually with software code and TMU will read current temperature from user value not from | |
14 | sensor's value. | |
15 | ||
bffd1f8a ADK |
16 | Enabling CONFIG_THERMAL_EMULATION option will make this support available. |
17 | When it's enabled, sysfs node will be created as | |
18 | /sys/devices/virtual/thermal/thermal_zone'zone id'/emul_temp. | |
bbf63be4 | 19 | |
bffd1f8a | 20 | The sysfs node, 'emul_node', will contain value 0 for the initial state. When you input any |
bbf63be4 JL |
21 | temperature you want to update to sysfs node, it automatically enable emulation mode and |
22 | current temperature will be changed into it. | |
f884ab15 | 23 | (Exynos also supports user changeable delay time which would be used to delay of |
bbf63be4 JL |
24 | changing temperature. However, this node only uses same delay of real sensing time, 938us.) |
25 | ||
26 | Exynos emulation mode requires synchronous of value changing and enabling. It means when you | |
27 | want to update the any value of delay or next temperature, then you have to enable emulation | |
28 | mode at the same time. (Or you have to keep the mode enabling.) If you don't, it fails to | |
29 | change the value to updated one and just use last succeessful value repeatedly. That's why | |
30 | this node gives users the right to change termerpature only. Just one interface makes it more | |
31 | simply to use. | |
32 | ||
33 | Disabling emulation mode only requires writing value 0 to sysfs node. | |
34 | ||
35 | ||
36 | TEMP 120 | | |
37 | | | |
38 | 100 | | |
39 | | | |
40 | 80 | | |
41 | | +----------- | |
42 | 60 | | | | |
43 | | +-------------| | | |
44 | 40 | | | | | |
45 | | | | | | |
46 | 20 | | | +---------- | |
47 | | | | | | | |
48 | 0 |______________|_____________|__________|__________|_________ | |
49 | A A A A TIME | |
50 | |<----->| |<----->| |<----->| | | |
51 | | 938us | | | | | | | |
52 | emulation : 0 50 | 70 | 20 | 0 | |
53 | current temp : sensor 50 70 20 sensor |