bffd1f8ac8
This removes the driver specific sysfs support of the temperature emulation and uses the newly added core thermal framework for thermal emulation. An exynos platform specific handler is added to support this. In this patch, the exynos senor(tmu) related code and exynos framework related (thermal zone, cooling devices) code are intentionally kept separate. So an emulated function pointer is passed from sensor to framework. This is beneficial in adding more sensor support using the same framework code which is an ongoing work. The goal is to finally split them totally. Even the existing read_temperature also follows the same execution method. Acked-by: Kukjin Kim <kgene.kim@samsung.com> Signed-off-by: Amit Daniel Kachhap <amit.daniel@samsung.com> Signed-off-by: Zhang Rui <rui.zhang@intel.com>
53 lines
2.2 KiB
Text
53 lines
2.2 KiB
Text
EXYNOS EMULATION MODE
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========================
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Copyright (C) 2012 Samsung Electronics
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Written by Jonghwa Lee <jonghwa3.lee@samsung.com>
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Description
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-----------
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Exynos 4x12 (4212, 4412) and 5 series provide emulation mode for thermal management unit.
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Thermal emulation mode supports software debug for TMU's operation. User can set temperature
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manually with software code and TMU will read current temperature from user value not from
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sensor's value.
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Enabling CONFIG_THERMAL_EMULATION option will make this support available.
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When it's enabled, sysfs node will be created as
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/sys/devices/virtual/thermal/thermal_zone'zone id'/emul_temp.
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The sysfs node, 'emul_node', will contain value 0 for the initial state. When you input any
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temperature you want to update to sysfs node, it automatically enable emulation mode and
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current temperature will be changed into it.
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(Exynos also supports user changable delay time which would be used to delay of
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changing temperature. However, this node only uses same delay of real sensing time, 938us.)
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Exynos emulation mode requires synchronous of value changing and enabling. It means when you
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want to update the any value of delay or next temperature, then you have to enable emulation
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mode at the same time. (Or you have to keep the mode enabling.) If you don't, it fails to
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change the value to updated one and just use last succeessful value repeatedly. That's why
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this node gives users the right to change termerpature only. Just one interface makes it more
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simply to use.
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Disabling emulation mode only requires writing value 0 to sysfs node.
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TEMP 120 |
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100 |
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80 |
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60 | | |
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40 | | | |
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20 | | | +----------
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0 |______________|_____________|__________|__________|_________
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A A A A TIME
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|<----->| |<----->| |<----->| |
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| 938us | | | | | |
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emulation : 0 50 | 70 | 20 | 0
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current temp : sensor 50 70 20 sensor
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