1 ===================== 2 Exynos Emulation Mode 3 ===================== 4 5 Copyright (C) 2012 Samsung Electronics 6 7 Written by Jonghwa Lee <jonghwa3.lee@samsung.com> 8 9 Description 10 ----------- 11 12 Exynos 4x12 (4212, 4412) and 5 series provide emulation mode for thermal 13 management unit. Thermal emulation mode supports software debug for 14 TMU's operation. User can set temperature manually with software code 15 and TMU will read current temperature from user value not from sensor's 16 value. 17 18 Enabling CONFIG_THERMAL_EMULATION option will make this support 19 available. When it's enabled, sysfs node will be created as 20 /sys/devices/virtual/thermal/thermal_zone'zone id'/emul_temp. 21 22 The sysfs node, 'emul_node', will contain value 0 for the initial state. 23 When you input any temperature you want to update to sysfs node, it 24 automatically enable emulation mode and current temperature will be 25 changed into it. 26 27 (Exynos also supports user changeable delay time which would be used to 28 delay of changing temperature. However, this node only uses same delay 29 of real sensing time, 938us.) 30 31 Exynos emulation mode requires synchronous of value changing and 32 enabling. It means when you want to update the any value of delay or 33 next temperature, then you have to enable emulation mode at the same 34 time. (Or you have to keep the mode enabling.) If you don't, it fails to 35 change the value to updated one and just use last succeessful value 36 repeatedly. That's why this node gives users the right to change 37 termerpature only. Just one interface makes it more simply to use. 38 39 Disabling emulation mode only requires writing value 0 to sysfs node. 40 41 :: 42 43 44 TEMP 120 | 45 | 46 100 | 47 | 48 80 | 49 | +----------- 50 60 | | | 51 | +-------------| | 52 40 | | | | 53 | | | | 54 20 | | | +---------- 55 | | | | | 56 0 |______________|_____________|__________|__________|_________ 57 A A A A TIME 58 |<----->| |<----->| |<----->| | 59 | 938us | | | | | | 60 emulation : 0 50 | 70 | 20 | 0 61 current temp: sensor 50 70 20 sensor
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