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Based on kernel version 3.9. Page generated on 2013-05-02 23:15 EST.

1	Kernel driver exynos4_tmu
2	=================
3	
4	Supported chips:
5	* ARM SAMSUNG EXYNOS4 series of SoC
6	  Prefix: 'exynos4-tmu'
7	  Datasheet: Not publicly available
8	
9	Authors: Donggeun Kim <dg77.kim@samsung.com>
10	
11	Description
12	-----------
13	
14	This driver allows to read temperature inside SAMSUNG EXYNOS4 series of SoC.
15	
16	The chip only exposes the measured 8-bit temperature code value
17	through a register.
18	Temperature can be taken from the temperature code.
19	There are three equations converting from temperature to temperature code.
20	
21	The three equations are:
22	  1. Two point trimming
23		Tc = (T - 25) * (TI2 - TI1) / (85 - 25) + TI1
24	
25	  2. One point trimming
26		Tc = T + TI1 - 25
27	
28	  3. No trimming
29		Tc = T + 50
30	
31	  Tc: Temperature code, T: Temperature,
32	  TI1: Trimming info for 25 degree Celsius (stored at TRIMINFO register)
33	       Temperature code measured at 25 degree Celsius which is unchanged
34	  TI2: Trimming info for 85 degree Celsius (stored at TRIMINFO register)
35	       Temperature code measured at 85 degree Celsius which is unchanged
36	
37	TMU(Thermal Management Unit) in EXYNOS4 generates interrupt
38	when temperature exceeds pre-defined levels.
39	The maximum number of configurable threshold is four.
40	The threshold levels are defined as follows:
41	  Level_0: current temperature > trigger_level_0 + threshold
42	  Level_1: current temperature > trigger_level_1 + threshold
43	  Level_2: current temperature > trigger_level_2 + threshold
44	  Level_3: current temperature > trigger_level_3 + threshold
45	
46	  The threshold and each trigger_level are set
47	  through the corresponding registers.
48	
49	When an interrupt occurs, this driver notify kernel thermal framework
50	with the function exynos4_report_trigger.
51	Although an interrupt condition for level_0 can be set,
52	it can be used to synchronize the cooling action.
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