Based on kernel version 4.16.1. Page generated on 2018-04-09 11:53 EST.
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 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. 19 20 The sysfs node, 'emul_node', will contain value 0 for the initial state. When you input any 21 temperature you want to update to sysfs node, it automatically enable emulation mode and 22 current temperature will be changed into it. 23 (Exynos also supports user changeable delay time which would be used to delay of 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