About Kernel Documentation Linux Kernel Contact Linux Resources Linux Blog

Documentation / hwmon / f71805f




Custom Search

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

1	Kernel driver f71805f
2	=====================
3	
4	Supported chips:
5	  * Fintek F71805F/FG
6	    Prefix: 'f71805f'
7	    Addresses scanned: none, address read from Super I/O config space
8	    Datasheet: Available from the Fintek website
9	  * Fintek F71806F/FG
10	    Prefix: 'f71872f'
11	    Addresses scanned: none, address read from Super I/O config space
12	    Datasheet: Available from the Fintek website
13	  * Fintek F71872F/FG
14	    Prefix: 'f71872f'
15	    Addresses scanned: none, address read from Super I/O config space
16	    Datasheet: Available from the Fintek website
17	
18	Author: Jean Delvare <jdelvare@suse.de>
19	
20	Thanks to Denis Kieft from Barracuda Networks for the donation of a
21	test system (custom Jetway K8M8MS motherboard, with CPU and RAM) and
22	for providing initial documentation.
23	
24	Thanks to Kris Chen and Aaron Huang from Fintek for answering technical
25	questions and providing additional documentation.
26	
27	Thanks to Chris Lin from Jetway for providing wiring schematics and
28	answering technical questions.
29	
30	
31	Description
32	-----------
33	
34	The Fintek F71805F/FG Super I/O chip includes complete hardware monitoring
35	capabilities. It can monitor up to 9 voltages (counting its own power
36	source), 3 fans and 3 temperature sensors.
37	
38	This chip also has fan controlling features, using either DC or PWM, in
39	three different modes (one manual, two automatic).
40	
41	The Fintek F71872F/FG Super I/O chip is almost the same, with two
42	additional internal voltages monitored (VSB and battery). It also features
43	6 VID inputs. The VID inputs are not yet supported by this driver.
44	
45	The Fintek F71806F/FG Super-I/O chip is essentially the same as the
46	F71872F/FG, and is undistinguishable therefrom.
47	
48	The driver assumes that no more than one chip is present, which seems
49	reasonable.
50	
51	
52	Voltage Monitoring
53	------------------
54	
55	Voltages are sampled by an 8-bit ADC with a LSB of 8 mV. The supported
56	range is thus from 0 to 2.040 V. Voltage values outside of this range
57	need external resistors. An exception is in0, which is used to monitor
58	the chip's own power source (+3.3V), and is divided internally by a
59	factor 2. For the F71872F/FG, in9 (VSB) and in10 (battery) are also
60	divided internally by a factor 2.
61	
62	The two LSB of the voltage limit registers are not used (always 0), so
63	you can only set the limits in steps of 32 mV (before scaling).
64	
65	The wirings and resistor values suggested by Fintek are as follow:
66	
67	        pin                                           expected
68	        name    use           R1      R2     divider  raw val.
69	
70	in0     VCC     VCC3.3V     int.    int.        2.00    1.65 V
71	in1     VIN1    VTT1.2V      10K       -        1.00    1.20 V
72	in2     VIN2    VRAM        100K    100K        2.00   ~1.25 V (1)
73	in3     VIN3    VCHIPSET     47K    100K        1.47    2.24 V (2)
74	in4     VIN4    VCC5V       200K     47K        5.25    0.95 V
75	in5     VIN5    +12V        200K     20K       11.00    1.05 V
76	in6     VIN6    VCC1.5V      10K       -        1.00    1.50 V
77	in7     VIN7    VCORE        10K       -        1.00   ~1.40 V (1)
78	in8     VIN8    VSB5V       200K     47K        1.00    0.95 V
79	in10    VSB     VSB3.3V     int.    int.        2.00    1.65 V (3)
80	in9     VBAT    VBATTERY    int.    int.        2.00    1.50 V (3)
81	
82	(1) Depends on your hardware setup.
83	(2) Obviously not correct, swapping R1 and R2 would make more sense.
84	(3) F71872F/FG only.
85	
86	These values can be used as hints at best, as motherboard manufacturers
87	are free to use a completely different setup. As a matter of fact, the
88	Jetway K8M8MS uses a significantly different setup. You will have to
89	find out documentation about your own motherboard, and edit sensors.conf
90	accordingly.
91	
92	Each voltage measured has associated low and high limits, each of which
93	triggers an alarm when crossed.
94	
95	
96	Fan Monitoring
97	--------------
98	
99	Fan rotation speeds are reported as 12-bit values from a gated clock
100	signal. Speeds down to 366 RPM can be measured. There is no theoretical
101	high limit, but values over 6000 RPM seem to cause problem. The effective
102	resolution is much lower than you would expect, the step between different
103	register values being 10 rather than 1.
104	
105	The chip assumes 2 pulse-per-revolution fans.
106	
107	An alarm is triggered if the rotation speed drops below a programmable
108	limit or is too low to be measured.
109	
110	
111	Temperature Monitoring
112	----------------------
113	
114	Temperatures are reported in degrees Celsius. Each temperature measured
115	has a high limit, those crossing triggers an alarm. There is an associated
116	hysteresis value, below which the temperature has to drop before the
117	alarm is cleared.
118	
119	All temperature channels are external, there is no embedded temperature
120	sensor. Each channel can be used for connecting either a thermal diode
121	or a thermistor. The driver reports the currently selected mode, but
122	doesn't allow changing it. In theory, the BIOS should have configured
123	everything properly.
124	
125	
126	Fan Control
127	-----------
128	
129	Both PWM (pulse-width modulation) and DC fan speed control methods are
130	supported. The right one to use depends on external circuitry on the
131	motherboard, so the driver assumes that the BIOS set the method
132	properly. The driver will report the method, but won't let you change
133	it.
134	
135	When the PWM method is used, you can select the operating frequency,
136	from 187.5 kHz (default) to 31 Hz. The best frequency depends on the
137	fan model. As a rule of thumb, lower frequencies seem to give better
138	control, but may generate annoying high-pitch noise. So a frequency just
139	above the audible range, such as 25 kHz, may be a good choice; if this
140	doesn't give you good linear control, try reducing it. Fintek recommends
141	not going below 1 kHz, as the fan tachometers get confused by lower
142	frequencies as well.
143	
144	When the DC method is used, Fintek recommends not going below 5 V, which
145	corresponds to a pwm value of 106 for the driver. The driver doesn't
146	enforce this limit though.
147	
148	Three different fan control modes are supported; the mode number is written
149	to the pwm<n>_enable file.
150	
151	* 1: Manual mode
152	  You ask for a specific PWM duty cycle or DC voltage by writing to the
153	  pwm<n> file.
154	
155	* 2: Temperature mode
156	  You define 3 temperature/fan speed trip points using the
157	  pwm<n>_auto_point<m>_temp and _fan files. These define a staircase
158	  relationship between temperature and fan speed with two additional points
159	  interpolated between the values that you define. When the temperature
160	  is below auto_point1_temp the fan is switched off.
161	
162	* 3: Fan speed mode
163	  You ask for a specific fan speed by writing to the fan<n>_target file.
164	
165	Both of the automatic modes require that pwm1 corresponds to fan1, pwm2 to
166	fan2 and pwm3 to fan3. Temperature mode also requires that temp1 corresponds
167	to pwm1 and fan1, etc.
Hide Line Numbers
About Kernel Documentation Linux Kernel Contact Linux Resources Linux Blog

Information is copyright its respective author. All material is available from the Linux Kernel Source distributed under a GPL License. This page is provided as a free service by mjmwired.net.