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Based on kernel version 3.9. Page generated on 2013-05-02 23:07 EST.

1	Kernel driver it87
2	==================
3	
4	Supported chips:
5	  * IT8705F
6	    Prefix: 'it87'
7	    Addresses scanned: from Super I/O config space (8 I/O ports)
8	    Datasheet: Once publicly available at the ITE website, but no longer
9	  * IT8712F
10	    Prefix: 'it8712'
11	    Addresses scanned: from Super I/O config space (8 I/O ports)
12	    Datasheet: Once publicly available at the ITE website, but no longer
13	  * IT8716F/IT8726F
14	    Prefix: 'it8716'
15	    Addresses scanned: from Super I/O config space (8 I/O ports)
16	    Datasheet: Once publicly available at the ITE website, but no longer
17	  * IT8718F
18	    Prefix: 'it8718'
19	    Addresses scanned: from Super I/O config space (8 I/O ports)
20	    Datasheet: Once publicly available at the ITE website, but no longer
21	  * IT8720F
22	    Prefix: 'it8720'
23	    Addresses scanned: from Super I/O config space (8 I/O ports)
24	    Datasheet: Not publicly available
25	  * IT8721F/IT8758E
26	    Prefix: 'it8721'
27	    Addresses scanned: from Super I/O config space (8 I/O ports)
28	    Datasheet: Not publicly available
29	  * IT8728F
30	    Prefix: 'it8728'
31	    Addresses scanned: from Super I/O config space (8 I/O ports)
32	    Datasheet: Not publicly available
33	  * IT8771E
34	    Prefix: 'it8771'
35	    Addresses scanned: from Super I/O config space (8 I/O ports)
36	    Datasheet: Not publicly available
37	  * IT8772E
38	    Prefix: 'it8772'
39	    Addresses scanned: from Super I/O config space (8 I/O ports)
40	    Datasheet: Not publicly available
41	  * IT8782F
42	    Prefix: 'it8782'
43	    Addresses scanned: from Super I/O config space (8 I/O ports)
44	    Datasheet: Not publicly available
45	  * IT8783E/F
46	    Prefix: 'it8783'
47	    Addresses scanned: from Super I/O config space (8 I/O ports)
48	    Datasheet: Not publicly available
49	  * SiS950   [clone of IT8705F]
50	    Prefix: 'it87'
51	    Addresses scanned: from Super I/O config space (8 I/O ports)
52	    Datasheet: No longer be available
53	
54	Authors:
55	    Christophe Gauthron
56	    Jean Delvare <khali@linux-fr.org>
57	
58	
59	Module Parameters
60	-----------------
61	
62	* update_vbat: int
63	
64	  0 if vbat should report power on value, 1 if vbat should be updated after
65	  each read. Default is 0. On some boards the battery voltage is provided
66	  by either the battery or the onboard power supply. Only the first reading
67	  at power on will be the actual battery voltage (which the chip does
68	  automatically). On other boards the battery voltage is always fed to
69	  the chip so can be read at any time. Excessive reading may decrease
70	  battery life but no information is given in the datasheet.
71	
72	* fix_pwm_polarity int
73	
74	  Force PWM polarity to active high (DANGEROUS). Some chips are
75	  misconfigured by BIOS - PWM values would be inverted. This option tries
76	  to fix this. Please contact your BIOS manufacturer and ask him for fix.
77	
78	
79	Hardware Interfaces
80	-------------------
81	
82	All the chips supported by this driver are LPC Super-I/O chips, accessed
83	through the LPC bus (ISA-like I/O ports). The IT8712F additionally has an
84	SMBus interface to the hardware monitoring functions. This driver no
85	longer supports this interface though, as it is slower and less reliable
86	than the ISA access, and was only available on a small number of
87	motherboard models.
88	
89	
90	Description
91	-----------
92	
93	This driver implements support for the IT8705F, IT8712F, IT8716F,
94	IT8718F, IT8720F, IT8721F, IT8726F, IT8728F, IT8758E, IT8771E, IT8772E,
95	IT8782F, IT8783E/F, and SiS950 chips.
96	
97	These chips are 'Super I/O chips', supporting floppy disks, infrared ports,
98	joysticks and other miscellaneous stuff. For hardware monitoring, they
99	include an 'environment controller' with 3 temperature sensors, 3 fan
100	rotation speed sensors, 8 voltage sensors, associated alarms, and chassis
101	intrusion detection.
102	
103	The IT8712F and IT8716F additionally feature VID inputs, used to report
104	the Vcore voltage of the processor. The early IT8712F have 5 VID pins,
105	the IT8716F and late IT8712F have 6. They are shared with other functions
106	though, so the functionality may not be available on a given system.
107	
108	The IT8718F and IT8720F also features VID inputs (up to 8 pins) but the value
109	is stored in the Super-I/O configuration space. Due to technical limitations,
110	this value can currently only be read once at initialization time, so
111	the driver won't notice and report changes in the VID value. The two
112	upper VID bits share their pins with voltage inputs (in5 and in6) so you
113	can't have both on a given board.
114	
115	The IT8716F, IT8718F, IT8720F, IT8721F/IT8758E and later IT8712F revisions
116	have support for 2 additional fans. The additional fans are supported by the
117	driver.
118	
119	The IT8716F, IT8718F, IT8720F, IT8721F/IT8758E, IT8782F, IT8783E/F, and late
120	IT8712F and IT8705F also have optional 16-bit tachometer counters for fans 1 to
121	3. This is better (no more fan clock divider mess) but not compatible with the
122	older chips and revisions. The 16-bit tachometer mode is enabled by the driver
123	when one of the above chips is detected.
124	
125	The IT8726F is just bit enhanced IT8716F with additional hardware
126	for AMD power sequencing. Therefore the chip will appear as IT8716F
127	to userspace applications.
128	
129	The IT8728F, IT8771E, and IT8772E are considered compatible with the IT8721F,
130	until a datasheet becomes available (hopefully.)
131	
132	Temperatures are measured in degrees Celsius. An alarm is triggered once
133	when the Overtemperature Shutdown limit is crossed.
134	
135	Fan rotation speeds are reported in RPM (rotations per minute). An alarm is
136	triggered if the rotation speed has dropped below a programmable limit. When
137	16-bit tachometer counters aren't used, fan readings can be divided by
138	a programmable divider (1, 2, 4 or 8) to give the readings more range or
139	accuracy. With a divider of 2, the lowest representable value is around
140	2600 RPM. Not all RPM values can accurately be represented, so some rounding
141	is done.
142	
143	Voltage sensors (also known as IN sensors) report their values in volts. An
144	alarm is triggered if the voltage has crossed a programmable minimum or
145	maximum limit. Note that minimum in this case always means 'closest to
146	zero'; this is important for negative voltage measurements. All voltage
147	inputs can measure voltages between 0 and 4.08 volts, with a resolution of
148	0.016 volt (except IT8721F/IT8758E and IT8728F: 0.012 volt.) The battery
149	voltage in8 does not have limit registers.
150	
151	On the IT8721F/IT8758E, IT8782F, and IT8783E/F, some voltage inputs are
152	internal and scaled inside the chip (in7 (optional for IT8782F and IT8783E/F),
153	in8 and optionally in3). The driver handles this transparently so user-space
154	doesn't have to care.
155	
156	The VID lines (IT8712F/IT8716F/IT8718F/IT8720F) encode the core voltage value:
157	the voltage level your processor should work with. This is hardcoded by
158	the mainboard and/or processor itself. It is a value in volts.
159	
160	If an alarm triggers, it will remain triggered until the hardware register
161	is read at least once. This means that the cause for the alarm may already
162	have disappeared! Note that in the current implementation, all hardware
163	registers are read whenever any data is read (unless it is less than 1.5
164	seconds since the last update). This means that you can easily miss
165	once-only alarms.
166	
167	Out-of-limit readings can also result in beeping, if the chip is properly
168	wired and configured. Beeping can be enabled or disabled per sensor type
169	(temperatures, voltages and fans.)
170	
171	The IT87xx only updates its values each 1.5 seconds; reading it more often
172	will do no harm, but will return 'old' values.
173	
174	To change sensor N to a thermistor, 'echo 4 > tempN_type' where N is 1, 2,
175	or 3. To change sensor N to a thermal diode, 'echo 3 > tempN_type'.
176	Give 0 for unused sensor. Any other value is invalid. To configure this at
177	startup, consult lm_sensors's /etc/sensors.conf. (4 = thermistor;
178	3 = thermal diode)
179	
180	
181	Fan speed control
182	-----------------
183	
184	The fan speed control features are limited to manual PWM mode. Automatic
185	"Smart Guardian" mode control handling is only implemented for older chips
186	(see below.) However if you want to go for "manual mode" just write 1 to
187	pwmN_enable.
188	
189	If you are only able to control the fan speed with very small PWM values,
190	try lowering the PWM base frequency (pwm1_freq). Depending on the fan,
191	it may give you a somewhat greater control range. The same frequency is
192	used to drive all fan outputs, which is why pwm2_freq and pwm3_freq are
193	read-only.
194	
195	
196	Automatic fan speed control (old interface)
197	-------------------------------------------
198	
199	The driver supports the old interface to automatic fan speed control
200	which is implemented by IT8705F chips up to revision F and IT8712F
201	chips up to revision G.
202	
203	This interface implements 4 temperature vs. PWM output trip points.
204	The PWM output of trip point 4 is always the maximum value (fan running
205	at full speed) while the PWM output of the other 3 trip points can be
206	freely chosen. The temperature of all 4 trip points can be freely chosen.
207	Additionally, trip point 1 has an hysteresis temperature attached, to
208	prevent fast switching between fan on and off.
209	
210	The chip automatically computes the PWM output value based on the input
211	temperature, based on this simple rule: if the temperature value is
212	between trip point N and trip point N+1 then the PWM output value is
213	the one of trip point N. The automatic control mode is less flexible
214	than the manual control mode, but it reacts faster, is more robust and
215	doesn't use CPU cycles.
216	
217	Trip points must be set properly before switching to automatic fan speed
218	control mode. The driver will perform basic integrity checks before
219	actually switching to automatic control mode.
220	
221	
222	Temperature offset attributes
223	-----------------------------
224	
225	The driver supports temp[1-3]_offset sysfs attributes to adjust the reported
226	temperature for thermal diodes or diode-connected thermal transistors.
227	If a temperature sensor is configured for thermistors, the attribute values
228	are ignored. If the thermal sensor type is Intel PECI, the temperature offset
229	must be programmed to the critical CPU temperature.
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