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Based on kernel version 3.9. Page generated on 2013-05-02 23:08 EST.

1	Kernel driver w83792d
2	=====================
3	
4	Supported chips:
5	  * Winbond W83792D
6	    Prefix: 'w83792d'
7	    Addresses scanned: I2C 0x2c - 0x2f
8	    Datasheet: http://www.winbond.com.tw
9	
10	Author: Chunhao Huang
11	Contact: DZShen <DZShen@Winbond.com.tw>
12	
13	
14	Module Parameters
15	-----------------
16	
17	* init int
18	  (default 1)
19	  Use 'init=0' to bypass initializing the chip.
20	  Try this if your computer crashes when you load the module.
21	
22	* force_subclients=bus,caddr,saddr,saddr
23	  This is used to force the i2c addresses for subclients of
24	  a certain chip. Example usage is `force_subclients=0,0x2f,0x4a,0x4b'
25	  to force the subclients of chip 0x2f on bus 0 to i2c addresses
26	  0x4a and 0x4b.
27	
28	
29	Description
30	-----------
31	
32	This driver implements support for the Winbond W83792AD/D.
33	
34	Detection of the chip can sometimes be foiled because it can be in an
35	internal state that allows no clean access (Bank with ID register is not
36	currently selected). If you know the address of the chip, use a 'force'
37	parameter; this will put it into a more well-behaved state first.
38	
39	The driver implements three temperature sensors, seven fan rotation speed
40	sensors, nine voltage sensors, and two automatic fan regulation
41	strategies called: Smart Fan I (Thermal Cruise mode) and Smart Fan II.
42	Automatic fan control mode is possible only for fan1-fan3. Fan4-fan7 can run
43	synchronized with selected fan (fan1-fan3). This functionality and manual PWM
44	control for fan4-fan7 is not yet implemented.
45	
46	Temperatures are measured in degrees Celsius and measurement resolution is 1
47	degC for temp1 and 0.5 degC for temp2 and temp3. An alarm is triggered when
48	the temperature gets higher than the Overtemperature Shutdown value; it stays
49	on until the temperature falls below the Hysteresis value.
50	
51	Fan rotation speeds are reported in RPM (rotations per minute). An alarm is
52	triggered if the rotation speed has dropped below a programmable limit. Fan
53	readings can be divided by a programmable divider (1, 2, 4, 8, 16, 32, 64 or
54	128) to give the readings more range or accuracy.
55	
56	Voltage sensors (also known as IN sensors) report their values in millivolts.
57	An alarm is triggered if the voltage has crossed a programmable minimum
58	or maximum limit.
59	
60	Alarms are provided as output from "realtime status register". Following bits
61	are defined:
62	
63	bit - alarm on:
64	0  - in0
65	1  - in1
66	2  - temp1
67	3  - temp2
68	4  - temp3
69	5  - fan1
70	6  - fan2
71	7  - fan3
72	8  - in2
73	9  - in3
74	10 - in4
75	11 - in5
76	12 - in6
77	13 - VID change
78	14 - chassis
79	15 - fan7
80	16 - tart1
81	17 - tart2
82	18 - tart3
83	19 - in7
84	20 - in8
85	21 - fan4
86	22 - fan5
87	23 - fan6
88	
89	Tart will be asserted while target temperature cannot be achieved after 3 minutes
90	of full speed rotation of corresponding fan.
91	
92	In addition to the alarms described above, there is a CHAS alarm on the chips
93	which triggers if your computer case is open (This one is latched, contrary
94	to realtime alarms).
95	
96	The chips only update values each 3 seconds; reading them more often will
97	do no harm, but will return 'old' values.
98	
99	
100	W83792D PROBLEMS
101	----------------
102	Known problems:
103		- This driver is only for Winbond W83792D C version device, there
104		  are also some motherboards with B version W83792D device. The
105		  calculation method to in6-in7(measured value, limits) is a little
106		  different between C and B version. C or B version can be identified
107		  by CR[0x49h].
108		- The function of vid and vrm has not been finished, because I'm NOT
109		  very familiar with them. Adding support is welcome.
110	 	- The function of chassis open detection needs more tests.
111		- If you have ASUS server board and chip was not found: Then you will
112		  need to upgrade to latest (or beta) BIOS. If it does not help please
113		  contact us.
114	
115	Fan control
116	-----------
117	
118	Manual mode
119	-----------
120	
121	Works as expected. You just need to specify desired PWM/DC value (fan speed)
122	in appropriate pwm# file.
123	
124	Thermal cruise
125	--------------
126	
127	In this mode, W83792D provides the Smart Fan system to automatically control
128	fan speed to keep the temperatures of CPU and the system within specific
129	range. At first a wanted temperature and interval must be set. This is done
130	via thermal_cruise# file. The tolerance# file serves to create T +- tolerance
131	interval. The fan speed will be lowered as long as the current temperature
132	remains below the thermal_cruise# +- tolerance# value. Once the temperature
133	exceeds the high limit (T+tolerance), the fan will be turned on with a
134	specific speed set by pwm# and automatically controlled its PWM duty cycle
135	with the temperature varying. Three conditions may occur:
136	
137	(1) If the temperature still exceeds the high limit, PWM duty
138	cycle will increase slowly.
139	
140	(2) If the temperature goes below the high limit, but still above the low
141	limit (T-tolerance), the fan speed will be fixed at the current speed because
142	the temperature is in the target range.
143	
144	(3) If the temperature goes below the low limit, PWM duty cycle will decrease
145	slowly to 0 or a preset stop value until the temperature exceeds the low
146	limit. (The preset stop value handling is not yet implemented in driver)
147	
148	Smart Fan II
149	------------
150	
151	W83792D also provides a special mode for fan. Four temperature points are
152	available. When related temperature sensors detects the temperature in preset
153	temperature region (sf2_point@_fan# +- tolerance#) it will cause fans to run
154	on programmed value from sf2_level@_fan#. You need to set four temperatures
155	for each fan.
156	
157	
158	/sys files
159	----------
160	
161	pwm[1-3] - this file stores PWM duty cycle or DC value (fan speed) in range:
162		0 (stop) to 255 (full)
163	pwm[1-3]_enable - this file controls mode of fan/temperature control:
164	            * 0 Disabled
165	            * 1 Manual mode
166	            * 2 Smart Fan II
167	            * 3 Thermal Cruise
168	pwm[1-3]_mode - Select PWM of DC mode
169	            * 0 DC
170	            * 1 PWM
171	thermal_cruise[1-3] - Selects the desired temperature for cruise (degC)
172	tolerance[1-3] - Value in degrees of Celsius (degC) for +- T
173	sf2_point[1-4]_fan[1-3] - four temperature points for each fan for Smart Fan II
174	sf2_level[1-3]_fan[1-3] - three PWM/DC levels for each fan for Smart Fan II
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