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

1	Kernel driver it87
2	==================
3	
4	Supported chips:
5	  * IT8603E/IT8623E
6	    Prefix: 'it8603'
7	    Addresses scanned: from Super I/O config space (8 I/O ports)
8	    Datasheet: Not publicly available
9	  * IT8705F
10	    Prefix: 'it87'
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	  * IT8712F
14	    Prefix: 'it8712'
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	  * IT8716F/IT8726F
18	    Prefix: 'it8716'
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	  * IT8718F
22	    Prefix: 'it8718'
23	    Addresses scanned: from Super I/O config space (8 I/O ports)
24	    Datasheet: Once publicly available at the ITE website, but no longer
25	  * IT8720F
26	    Prefix: 'it8720'
27	    Addresses scanned: from Super I/O config space (8 I/O ports)
28	    Datasheet: Not publicly available
29	  * IT8721F/IT8758E
30	    Prefix: 'it8721'
31	    Addresses scanned: from Super I/O config space (8 I/O ports)
32	    Datasheet: Not publicly available
33	  * IT8728F
34	    Prefix: 'it8728'
35	    Addresses scanned: from Super I/O config space (8 I/O ports)
36	    Datasheet: Not publicly available
37	  * IT8771E
38	    Prefix: 'it8771'
39	    Addresses scanned: from Super I/O config space (8 I/O ports)
40	    Datasheet: Not publicly available
41	  * IT8772E
42	    Prefix: 'it8772'
43	    Addresses scanned: from Super I/O config space (8 I/O ports)
44	    Datasheet: Not publicly available
45	  * IT8782F
46	    Prefix: 'it8782'
47	    Addresses scanned: from Super I/O config space (8 I/O ports)
48	    Datasheet: Not publicly available
49	  * IT8783E/F
50	    Prefix: 'it8783'
51	    Addresses scanned: from Super I/O config space (8 I/O ports)
52	    Datasheet: Not publicly available
53	  * SiS950   [clone of IT8705F]
54	    Prefix: 'it87'
55	    Addresses scanned: from Super I/O config space (8 I/O ports)
56	    Datasheet: No longer be available
57	
58	Authors:
59	    Christophe Gauthron
60	    Jean Delvare <jdelvare@suse.de>
61	
62	
63	Module Parameters
64	-----------------
65	
66	* update_vbat: int
67	
68	  0 if vbat should report power on value, 1 if vbat should be updated after
69	  each read. Default is 0. On some boards the battery voltage is provided
70	  by either the battery or the onboard power supply. Only the first reading
71	  at power on will be the actual battery voltage (which the chip does
72	  automatically). On other boards the battery voltage is always fed to
73	  the chip so can be read at any time. Excessive reading may decrease
74	  battery life but no information is given in the datasheet.
75	
76	* fix_pwm_polarity int
77	
78	  Force PWM polarity to active high (DANGEROUS). Some chips are
79	  misconfigured by BIOS - PWM values would be inverted. This option tries
80	  to fix this. Please contact your BIOS manufacturer and ask him for fix.
81	
82	
83	Hardware Interfaces
84	-------------------
85	
86	All the chips supported by this driver are LPC Super-I/O chips, accessed
87	through the LPC bus (ISA-like I/O ports). The IT8712F additionally has an
88	SMBus interface to the hardware monitoring functions. This driver no
89	longer supports this interface though, as it is slower and less reliable
90	than the ISA access, and was only available on a small number of
91	motherboard models.
92	
93	
94	Description
95	-----------
96	
97	This driver implements support for the IT8603E, IT8623E, IT8705F, IT8712F,
98	IT8716F, IT8718F, IT8720F, IT8721F, IT8726F, IT8728F, IT8758E, IT8771E,
99	IT8772E, IT8782F, IT8783E/F, and SiS950 chips.
100	
101	These chips are 'Super I/O chips', supporting floppy disks, infrared ports,
102	joysticks and other miscellaneous stuff. For hardware monitoring, they
103	include an 'environment controller' with 3 temperature sensors, 3 fan
104	rotation speed sensors, 8 voltage sensors, associated alarms, and chassis
105	intrusion detection.
106	
107	The IT8712F and IT8716F additionally feature VID inputs, used to report
108	the Vcore voltage of the processor. The early IT8712F have 5 VID pins,
109	the IT8716F and late IT8712F have 6. They are shared with other functions
110	though, so the functionality may not be available on a given system.
111	
112	The IT8718F and IT8720F also features VID inputs (up to 8 pins) but the value
113	is stored in the Super-I/O configuration space. Due to technical limitations,
114	this value can currently only be read once at initialization time, so
115	the driver won't notice and report changes in the VID value. The two
116	upper VID bits share their pins with voltage inputs (in5 and in6) so you
117	can't have both on a given board.
118	
119	The IT8716F, IT8718F, IT8720F, IT8721F/IT8758E and later IT8712F revisions
120	have support for 2 additional fans. The additional fans are supported by the
121	driver.
122	
123	The IT8716F, IT8718F, IT8720F, IT8721F/IT8758E, IT8782F, IT8783E/F, and late
124	IT8712F and IT8705F also have optional 16-bit tachometer counters for fans 1 to
125	3. This is better (no more fan clock divider mess) but not compatible with the
126	older chips and revisions. The 16-bit tachometer mode is enabled by the driver
127	when one of the above chips is detected.
128	
129	The IT8726F is just bit enhanced IT8716F with additional hardware
130	for AMD power sequencing. Therefore the chip will appear as IT8716F
131	to userspace applications.
132	
133	The IT8728F, IT8771E, and IT8772E are considered compatible with the IT8721F,
134	until a datasheet becomes available (hopefully.)
135	
136	The IT8603E/IT8623E is a custom design, hardware monitoring part is similar to
137	IT8728F. It only supports 16-bit fan mode, the full speed mode of the
138	fan is not supported (value 0 of pwmX_enable).
139	
140	Temperatures are measured in degrees Celsius. An alarm is triggered once
141	when the Overtemperature Shutdown limit is crossed.
142	
143	Fan rotation speeds are reported in RPM (rotations per minute). An alarm is
144	triggered if the rotation speed has dropped below a programmable limit. When
145	16-bit tachometer counters aren't used, fan readings can be divided by
146	a programmable divider (1, 2, 4 or 8) to give the readings more range or
147	accuracy. With a divider of 2, the lowest representable value is around
148	2600 RPM. Not all RPM values can accurately be represented, so some rounding
149	is done.
150	
151	Voltage sensors (also known as IN sensors) report their values in volts. An
152	alarm is triggered if the voltage has crossed a programmable minimum or
153	maximum limit. Note that minimum in this case always means 'closest to
154	zero'; this is important for negative voltage measurements. All voltage
155	inputs can measure voltages between 0 and 4.08 volts, with a resolution of
156	0.016 volt (except IT8603E, IT8721F/IT8758E and IT8728F: 0.012 volt.) The
157	battery voltage in8 does not have limit registers.
158	
159	On the IT8603E, IT8721F/IT8758E, IT8782F, and IT8783E/F, some voltage inputs
160	are internal and scaled inside the chip:
161	* in3 (optional)
162	* in7 (optional for IT8782F and IT8783E/F)
163	* in8 (always)
164	* in9 (relevant for IT8603E only)
165	The driver handles this transparently so user-space doesn't have to care.
166	
167	The VID lines (IT8712F/IT8716F/IT8718F/IT8720F) encode the core voltage value:
168	the voltage level your processor should work with. This is hardcoded by
169	the mainboard and/or processor itself. It is a value in volts.
170	
171	If an alarm triggers, it will remain triggered until the hardware register
172	is read at least once. This means that the cause for the alarm may already
173	have disappeared! Note that in the current implementation, all hardware
174	registers are read whenever any data is read (unless it is less than 1.5
175	seconds since the last update). This means that you can easily miss
176	once-only alarms.
177	
178	Out-of-limit readings can also result in beeping, if the chip is properly
179	wired and configured. Beeping can be enabled or disabled per sensor type
180	(temperatures, voltages and fans.)
181	
182	The IT87xx only updates its values each 1.5 seconds; reading it more often
183	will do no harm, but will return 'old' values.
184	
185	To change sensor N to a thermistor, 'echo 4 > tempN_type' where N is 1, 2,
186	or 3. To change sensor N to a thermal diode, 'echo 3 > tempN_type'.
187	Give 0 for unused sensor. Any other value is invalid. To configure this at
188	startup, consult lm_sensors's /etc/sensors.conf. (4 = thermistor;
189	3 = thermal diode)
190	
191	
192	Fan speed control
193	-----------------
194	
195	The fan speed control features are limited to manual PWM mode. Automatic
196	"Smart Guardian" mode control handling is only implemented for older chips
197	(see below.) However if you want to go for "manual mode" just write 1 to
198	pwmN_enable.
199	
200	If you are only able to control the fan speed with very small PWM values,
201	try lowering the PWM base frequency (pwm1_freq). Depending on the fan,
202	it may give you a somewhat greater control range. The same frequency is
203	used to drive all fan outputs, which is why pwm2_freq and pwm3_freq are
204	read-only.
205	
206	
207	Automatic fan speed control (old interface)
208	-------------------------------------------
209	
210	The driver supports the old interface to automatic fan speed control
211	which is implemented by IT8705F chips up to revision F and IT8712F
212	chips up to revision G.
213	
214	This interface implements 4 temperature vs. PWM output trip points.
215	The PWM output of trip point 4 is always the maximum value (fan running
216	at full speed) while the PWM output of the other 3 trip points can be
217	freely chosen. The temperature of all 4 trip points can be freely chosen.
218	Additionally, trip point 1 has an hysteresis temperature attached, to
219	prevent fast switching between fan on and off.
220	
221	The chip automatically computes the PWM output value based on the input
222	temperature, based on this simple rule: if the temperature value is
223	between trip point N and trip point N+1 then the PWM output value is
224	the one of trip point N. The automatic control mode is less flexible
225	than the manual control mode, but it reacts faster, is more robust and
226	doesn't use CPU cycles.
227	
228	Trip points must be set properly before switching to automatic fan speed
229	control mode. The driver will perform basic integrity checks before
230	actually switching to automatic control mode.
231	
232	
233	Temperature offset attributes
234	-----------------------------
235	
236	The driver supports temp[1-3]_offset sysfs attributes to adjust the reported
237	temperature for thermal diodes or diode-connected thermal transistors.
238	If a temperature sensor is configured for thermistors, the attribute values
239	are ignored. If the thermal sensor type is Intel PECI, the temperature offset
240	must be programmed to the critical CPU temperature.
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