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authorYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 12:17:53 -0700
committerYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 15:44:42 -0700
commit9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 (patch)
tree1c9cafbcd35f783a87880a10f85d1a060db1a563 /kernel/Documentation/thermal/exynos_thermal_emulation
parent98260f3884f4a202f9ca5eabed40b1354c489b29 (diff)
Add the rt linux 4.1.3-rt3 as base
Import the rt linux 4.1.3-rt3 as OPNFV kvm base. It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and the base is: commit 0917f823c59692d751951bf5ea699a2d1e2f26a2 Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Date: Sat Jul 25 12:13:34 2015 +0200 Prepare v4.1.3-rt3 Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> We lose all the git history this way and it's not good. We should apply another opnfv project repo in future. Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423 Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>
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+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