| EXYNOS EMULATION MODE |
| ======================== |
| |
| Copyright (C) 2012 Samsung Electronics |
| |
| Written by Jonghwa Lee <jonghwa3.lee@samsung.com> |
| |
| Description |
| ----------- |
| |
| Exynos 4x12 (4212, 4412) and 5 series provide emulation mode for thermal management unit. |
| Thermal emulation mode supports software debug for TMU's operation. User can set temperature |
| manually with software code and TMU will read current temperature from user value not from |
| sensor's value. |
| |
| Enabling CONFIG_THERMAL_EMULATION option will make this support available. |
| When it's enabled, sysfs node will be created as |
| /sys/devices/virtual/thermal/thermal_zone'zone id'/emul_temp. |
| |
| The sysfs node, 'emul_node', will contain value 0 for the initial state. When you input any |
| temperature you want to update to sysfs node, it automatically enable emulation mode and |
| current temperature will be changed into it. |
| (Exynos also supports user changeable delay time which would be used to delay of |
| changing temperature. However, this node only uses same delay of real sensing time, 938us.) |
| |
| Exynos emulation mode requires synchronous of value changing and enabling. It means when you |
| want to update the any value of delay or next temperature, then you have to enable emulation |
| mode at the same time. (Or you have to keep the mode enabling.) If you don't, it fails to |
| change the value to updated one and just use last succeessful value repeatedly. That's why |
| this node gives users the right to change termerpature only. Just one interface makes it more |
| simply to use. |
| |
| Disabling emulation mode only requires writing value 0 to sysfs node. |
| |
| |
| TEMP 120 | |
| | |
| 100 | |
| | |
| 80 | |
| | +----------- |
| 60 | | | |
| | +-------------| | |
| 40 | | | | |
| | | | | |
| 20 | | | +---------- |
| | | | | | |
| 0 |______________|_____________|__________|__________|_________ |
| A A A A TIME |
| |<----->| |<----->| |<----->| | |
| | 938us | | | | | | |
| emulation : 0 50 | 70 | 20 | 0 |
| current temp : sensor 50 70 20 sensor |
