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Based on kernel version 3.6.1. Page generated on 2012-10-11 09:35 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 user space of
50	one of four threshold levels for the interrupt
51	through kobject_uevent_env and sysfs_notify functions.
52	Although an interrupt condition for level_0 can be set,
53	it is not notified to user space through sysfs_notify function.
54	
55	Sysfs Interface
56	---------------
57	name		name of the temperature sensor
58			RO
59	
60	temp1_input	temperature
61			RO
62	
63	temp1_max	temperature for level_1 interrupt
64			RO
65	
66	temp1_crit	temperature for level_2 interrupt
67			RO
68	
69	temp1_emergency	temperature for level_3 interrupt
70			RO
71	
72	temp1_max_alarm	alarm for level_1 interrupt
73			RO
74	
75	temp1_crit_alarm
76			alarm for level_2 interrupt
77			RO
78	
79	temp1_emergency_alarm
80			alarm for level_3 interrupt
81			RO
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