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Based on kernel version 3.16. Page generated on 2014-08-06 21:39 EST.

1	Kernel driver adt7462
2	======================
3	
4	Supported chips:
5	  * Analog Devices ADT7462
6	    Prefix: 'adt7462'
7	    Addresses scanned: I2C 0x58, 0x5C
8	    Datasheet: Publicly available at the Analog Devices website
9	
10	Author: Darrick J. Wong
11	
12	Description
13	-----------
14	
15	This driver implements support for the Analog Devices ADT7462 chip family.
16	
17	This chip is a bit of a beast.  It has 8 counters for measuring fan speed.  It
18	can also measure 13 voltages or 4 temperatures, or various combinations of the
19	two.  See the chip documentation for more details about the exact set of
20	configurations.  This driver does not allow one to configure the chip; that is
21	left to the system designer.
22	
23	A sophisticated control system for the PWM outputs is designed into the ADT7462
24	that allows fan speed to be adjusted automatically based on any of the three
25	temperature sensors. Each PWM output is individually adjustable and
26	programmable. Once configured, the ADT7462 will adjust the PWM outputs in
27	response to the measured temperatures without further host intervention.  This
28	feature can also be disabled for manual control of the PWM's.
29	
30	Each of the measured inputs (voltage, temperature, fan speed) has
31	corresponding high/low limit values. The ADT7462 will signal an ALARM if
32	any measured value exceeds either limit.
33	
34	The ADT7462 samples all inputs continuously. The driver will not read
35	the registers more often than once every other second. Further,
36	configuration data is only read once per minute.
37	
38	Special Features
39	----------------
40	
41	The ADT7462 have a 10-bit ADC and can therefore measure temperatures
42	with 0.25 degC resolution.
43	
44	The Analog Devices datasheet is very detailed and describes a procedure for
45	determining an optimal configuration for the automatic PWM control.
46	
47	The driver will report sensor labels when it is able to determine that
48	information from the configuration registers.
49	
50	Configuration Notes
51	-------------------
52	
53	Besides standard interfaces driver adds the following:
54	
55	* PWM Control
56	
57	* pwm#_auto_point1_pwm and temp#_auto_point1_temp and
58	* pwm#_auto_point2_pwm and temp#_auto_point2_temp -
59	
60	point1: Set the pwm speed at a lower temperature bound.
61	point2: Set the pwm speed at a higher temperature bound.
62	
63	The ADT7462 will scale the pwm between the lower and higher pwm speed when
64	the temperature is between the two temperature boundaries.  PWM values range
65	from 0 (off) to 255 (full speed).  Fan speed will be set to maximum when the
66	temperature sensor associated with the PWM control exceeds temp#_max.
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