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R.Marek@sh.cvut.cz7f15b662005-05-26 12:42:19 +00001Kernel driver it87
2==================
3
4Supported chips:
5 * IT8705F
6 Prefix: 'it87'
Jean Delvare91749992005-10-08 00:10:00 +02007 Addresses scanned: from Super I/O config space (8 I/O ports)
Jean Delvare404a5522010-03-05 22:17:21 +01008 Datasheet: Once publicly available at the ITE website, but no longer
R.Marek@sh.cvut.cz7f15b662005-05-26 12:42:19 +00009 * IT8712F
10 Prefix: 'it8712'
Jean Delvare8e9afcb2006-12-12 18:18:28 +010011 Addresses scanned: from Super I/O config space (8 I/O ports)
Jean Delvare404a5522010-03-05 22:17:21 +010012 Datasheet: Once publicly available at the ITE website, but no longer
Rudolf Marek08a8f6e2007-06-09 10:11:16 -040013 * IT8716F/IT8726F
Jean Delvare17d648b2006-08-28 14:23:46 +020014 Prefix: 'it8716'
15 Addresses scanned: from Super I/O config space (8 I/O ports)
Jean Delvare404a5522010-03-05 22:17:21 +010016 Datasheet: Once publicly available at the ITE website, but no longer
Jean Delvare87673dd2006-08-28 14:37:19 +020017 * IT8718F
18 Prefix: 'it8718'
19 Addresses scanned: from Super I/O config space (8 I/O ports)
Jean Delvare404a5522010-03-05 22:17:21 +010020 Datasheet: Once publicly available at the ITE website, but no longer
Jean-Marc Spaggiarib4da93e2009-01-07 16:37:32 +010021 * IT8720F
22 Prefix: 'it8720'
23 Addresses scanned: from Super I/O config space (8 I/O ports)
Jean Delvare404a5522010-03-05 22:17:21 +010024 Datasheet: Not publicly available
R.Marek@sh.cvut.cz7f15b662005-05-26 12:42:19 +000025 * SiS950 [clone of IT8705F]
Jean Delvare91749992005-10-08 00:10:00 +020026 Prefix: 'it87'
27 Addresses scanned: from Super I/O config space (8 I/O ports)
R.Marek@sh.cvut.cz7f15b662005-05-26 12:42:19 +000028 Datasheet: No longer be available
29
Jean Delvareb19367c2006-08-28 14:39:26 +020030Authors:
Jean Delvaref1d8e332007-11-25 16:14:44 +010031 Christophe Gauthron
Jean Delvareb19367c2006-08-28 14:39:26 +020032 Jean Delvare <khali@linux-fr.org>
R.Marek@sh.cvut.cz7f15b662005-05-26 12:42:19 +000033
34
35Module Parameters
36-----------------
37
38* update_vbat: int
39
40 0 if vbat should report power on value, 1 if vbat should be updated after
41 each read. Default is 0. On some boards the battery voltage is provided
42 by either the battery or the onboard power supply. Only the first reading
43 at power on will be the actual battery voltage (which the chip does
44 automatically). On other boards the battery voltage is always fed to
45 the chip so can be read at any time. Excessive reading may decrease
46 battery life but no information is given in the datasheet.
47
48* fix_pwm_polarity int
49
50 Force PWM polarity to active high (DANGEROUS). Some chips are
51 misconfigured by BIOS - PWM values would be inverted. This option tries
52 to fix this. Please contact your BIOS manufacturer and ask him for fix.
53
Jean Delvare8e9afcb2006-12-12 18:18:28 +010054
55Hardware Interfaces
56-------------------
57
58All the chips suported by this driver are LPC Super-I/O chips, accessed
59through the LPC bus (ISA-like I/O ports). The IT8712F additionally has an
60SMBus interface to the hardware monitoring functions. This driver no
61longer supports this interface though, as it is slower and less reliable
62than the ISA access, and was only available on a small number of
63motherboard models.
64
65
R.Marek@sh.cvut.cz7f15b662005-05-26 12:42:19 +000066Description
67-----------
68
Jean Delvare87673dd2006-08-28 14:37:19 +020069This driver implements support for the IT8705F, IT8712F, IT8716F,
Jean-Marc Spaggiarib4da93e2009-01-07 16:37:32 +010070IT8718F, IT8720F, IT8726F and SiS950 chips.
R.Marek@sh.cvut.cz7f15b662005-05-26 12:42:19 +000071
72These chips are 'Super I/O chips', supporting floppy disks, infrared ports,
73joysticks and other miscellaneous stuff. For hardware monitoring, they
74include an 'environment controller' with 3 temperature sensors, 3 fan
75rotation speed sensors, 8 voltage sensors, and associated alarms.
76
Jean Delvare17d648b2006-08-28 14:23:46 +020077The IT8712F and IT8716F additionally feature VID inputs, used to report
78the Vcore voltage of the processor. The early IT8712F have 5 VID pins,
79the IT8716F and late IT8712F have 6. They are shared with other functions
80though, so the functionality may not be available on a given system.
Jean Delvare17d648b2006-08-28 14:23:46 +020081
Jean-Marc Spaggiarib4da93e2009-01-07 16:37:32 +010082The IT8718F and IT8720F also features VID inputs (up to 8 pins) but the value
83is stored in the Super-I/O configuration space. Due to technical limitations,
Jean Delvare87673dd2006-08-28 14:37:19 +020084this value can currently only be read once at initialization time, so
85the driver won't notice and report changes in the VID value. The two
86upper VID bits share their pins with voltage inputs (in5 and in6) so you
87can't have both on a given board.
Jean Delvare17d648b2006-08-28 14:23:46 +020088
Jean-Marc Spaggiarib4da93e2009-01-07 16:37:32 +010089The IT8716F, IT8718F, IT8720F and later IT8712F revisions have support for
Andrew Paprocki04751692008-08-06 22:41:06 +0200902 additional fans. The additional fans are supported by the driver.
Jean Delvare87673dd2006-08-28 14:37:19 +020091
Jean-Marc Spaggiarib4da93e2009-01-07 16:37:32 +010092The IT8716F, IT8718F and IT8720F, and late IT8712F and IT8705F also have
93optional 16-bit tachometer counters for fans 1 to 3. This is better (no more
94fan clock divider mess) but not compatible with the older chips and
Andrew Paprocki816d8c62008-08-06 22:41:06 +020095revisions. The 16-bit tachometer mode is enabled by the driver when one
96of the above chips is detected.
Jean Delvare17d648b2006-08-28 14:23:46 +020097
Rudolf Marek08a8f6e2007-06-09 10:11:16 -040098The IT8726F is just bit enhanced IT8716F with additional hardware
99for AMD power sequencing. Therefore the chip will appear as IT8716F
100to userspace applications.
101
R.Marek@sh.cvut.cz7f15b662005-05-26 12:42:19 +0000102Temperatures are measured in degrees Celsius. An alarm is triggered once
103when the Overtemperature Shutdown limit is crossed.
104
105Fan rotation speeds are reported in RPM (rotations per minute). An alarm is
Jean Delvare17d648b2006-08-28 14:23:46 +0200106triggered if the rotation speed has dropped below a programmable limit. When
10716-bit tachometer counters aren't used, fan readings can be divided by
108a programmable divider (1, 2, 4 or 8) to give the readings more range or
109accuracy. With a divider of 2, the lowest representable value is around
1102600 RPM. Not all RPM values can accurately be represented, so some rounding
111is done.
R.Marek@sh.cvut.cz7f15b662005-05-26 12:42:19 +0000112
113Voltage sensors (also known as IN sensors) report their values in volts. An
114alarm is triggered if the voltage has crossed a programmable minimum or
115maximum limit. Note that minimum in this case always means 'closest to
116zero'; this is important for negative voltage measurements. All voltage
117inputs can measure voltages between 0 and 4.08 volts, with a resolution of
1180.016 volt. The battery voltage in8 does not have limit registers.
119
Jean-Marc Spaggiarib4da93e2009-01-07 16:37:32 +0100120The VID lines (IT8712F/IT8716F/IT8718F/IT8720F) encode the core voltage value:
Jean Delvare87673dd2006-08-28 14:37:19 +0200121the voltage level your processor should work with. This is hardcoded by
122the mainboard and/or processor itself. It is a value in volts.
R.Marek@sh.cvut.cz7f15b662005-05-26 12:42:19 +0000123
124If an alarm triggers, it will remain triggered until the hardware register
125is read at least once. This means that the cause for the alarm may already
126have disappeared! Note that in the current implementation, all hardware
127registers are read whenever any data is read (unless it is less than 1.5
128seconds since the last update). This means that you can easily miss
129once-only alarms.
130
Jean Delvared9b327c2010-03-05 22:17:17 +0100131Out-of-limit readings can also result in beeping, if the chip is properly
132wired and configured. Beeping can be enabled or disabled per sensor type
133(temperatures, voltages and fans.)
134
R.Marek@sh.cvut.cz7f15b662005-05-26 12:42:19 +0000135The IT87xx only updates its values each 1.5 seconds; reading it more often
136will do no harm, but will return 'old' values.
137
Jean Delvare4ed10772008-10-17 17:51:16 +0200138To change sensor N to a thermistor, 'echo 4 > tempN_type' where N is 1, 2,
R.Marek@sh.cvut.cz7f15b662005-05-26 12:42:19 +0000139or 3. To change sensor N to a thermal diode, 'echo 3 > tempN_type'.
140Give 0 for unused sensor. Any other value is invalid. To configure this at
Jean Delvare4ed10772008-10-17 17:51:16 +0200141startup, consult lm_sensors's /etc/sensors.conf. (4 = thermistor;
R.Marek@sh.cvut.cz7f15b662005-05-26 12:42:19 +00001423 = thermal diode)
143
Jean Delvaref8d0c192007-02-14 21:15:02 +0100144
145Fan speed control
146-----------------
147
R.Marek@sh.cvut.cz7f15b662005-05-26 12:42:19 +0000148The fan speed control features are limited to manual PWM mode. Automatic
Jean Delvare4f3f51b2010-03-05 22:17:21 +0100149"Smart Guardian" mode control handling is only implemented for older chips
150(see below.) However if you want to go for "manual mode" just write 1 to
151pwmN_enable.
Jean Delvaref8d0c192007-02-14 21:15:02 +0100152
153If you are only able to control the fan speed with very small PWM values,
154try lowering the PWM base frequency (pwm1_freq). Depending on the fan,
155it may give you a somewhat greater control range. The same frequency is
156used to drive all fan outputs, which is why pwm2_freq and pwm3_freq are
157read-only.
Jean Delvare4f3f51b2010-03-05 22:17:21 +0100158
159
160Automatic fan speed control (old interface)
161-------------------------------------------
162
163The driver supports the old interface to automatic fan speed control
164which is implemented by IT8705F chips up to revision F and IT8712F
165chips up to revision G.
166
167This interface implements 4 temperature vs. PWM output trip points.
168The PWM output of trip point 4 is always the maximum value (fan running
169at full speed) while the PWM output of the other 3 trip points can be
170freely chosen. The temperature of all 4 trip points can be freely chosen.
171Additionally, trip point 1 has an hysteresis temperature attached, to
172prevent fast switching between fan on and off.
173
174The chip automatically computes the PWM output value based on the input
175temperature, based on this simple rule: if the temperature value is
176between trip point N and trip point N+1 then the PWM output value is
177the one of trip point N. The automatic control mode is less flexible
178than the manual control mode, but it reacts faster, is more robust and
179doesn't use CPU cycles.
Jean Delvarecccfc9c2010-03-05 22:17:21 +0100180
181Trip points must be set properly before switching to automatic fan speed
182control mode. The driver will perform basic integrity checks before
183actually switching to automatic control mode.