| ===================== |
| 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 that value changes and enabling are performed |
| synchronously. This means that when you want to update any value, such as the |
| delay or the next temperature, you must enable emulation mode at the same |
| time (or keep the mode enabled). If you do not, the value will fail to update |
| and the last successful value will continue to be used. For this reason, |
| this node only allows users to change the temperature. Providing a single |
| interface makes it simpler 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 |
