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1Kernel driver it87
2==================
3
4Supported chips:
5  * IT8705F
6    Prefix: 'it87'
7    Addresses scanned: from Super I/O config space (8 I/O ports)
8    Datasheet: Publicly available at the ITE website
9               http://www.ite.com.tw/product_info/file/pc/IT8705F_V.0.4.1.pdf
10  * IT8712F
11    Prefix: 'it8712'
12    Addresses scanned: from Super I/O config space (8 I/O ports)
13    Datasheet: Publicly available at the ITE website
14               http://www.ite.com.tw/product_info/file/pc/IT8712F_V0.9.1.pdf
15               http://www.ite.com.tw/product_info/file/pc/Errata%20V0.1%20for%20IT8712F%20V0.9.1.pdf
16               http://www.ite.com.tw/product_info/file/pc/IT8712F_V0.9.3.pdf
17  * IT8716F/IT8726F
18    Prefix: 'it8716'
19    Addresses scanned: from Super I/O config space (8 I/O ports)
20    Datasheet: Publicly available at the ITE website
21               http://www.ite.com.tw/product_info/file/pc/IT8716F_V0.3.ZIP
22               http://www.ite.com.tw/product_info/file/pc/IT8726F_V0.3.pdf
23  * IT8718F
24    Prefix: 'it8718'
25    Addresses scanned: from Super I/O config space (8 I/O ports)
26    Datasheet: Publicly available at the ITE website
27               http://www.ite.com.tw/product_info/file/pc/IT8718F_V0.2.zip
28               http://www.ite.com.tw/product_info/file/pc/IT8718F_V0%203_(for%20C%20version).zip
29  * IT8720F
30    Prefix: 'it8720'
31    Addresses scanned: from Super I/O config space (8 I/O ports)
32    Datasheet: Not yet publicly available.
33  * SiS950   [clone of IT8705F]
34    Prefix: 'it87'
35    Addresses scanned: from Super I/O config space (8 I/O ports)
36    Datasheet: No longer be available
37
38Authors:
39    Christophe Gauthron
40    Jean Delvare <khali@linux-fr.org>
41
42
43Module Parameters
44-----------------
45
46* update_vbat: int
47
48  0 if vbat should report power on value, 1 if vbat should be updated after
49  each read. Default is 0. On some boards the battery voltage is provided
50  by either the battery or the onboard power supply. Only the first reading
51  at power on will be the actual battery voltage (which the chip does
52  automatically). On other boards the battery voltage is always fed to
53  the chip so can be read at any time. Excessive reading may decrease
54  battery life but no information is given in the datasheet.
55
56* fix_pwm_polarity int
57
58  Force PWM polarity to active high (DANGEROUS). Some chips are
59  misconfigured by BIOS - PWM values would be inverted. This option tries
60  to fix this. Please contact your BIOS manufacturer and ask him for fix.
61
62
63Hardware Interfaces
64-------------------
65
66All the chips suported by this driver are LPC Super-I/O chips, accessed
67through the LPC bus (ISA-like I/O ports). The IT8712F additionally has an
68SMBus interface to the hardware monitoring functions. This driver no
69longer supports this interface though, as it is slower and less reliable
70than the ISA access, and was only available on a small number of
71motherboard models.
72
73
74Description
75-----------
76
77This driver implements support for the IT8705F, IT8712F, IT8716F,
78IT8718F, IT8720F, IT8726F and SiS950 chips.
79
80These chips are 'Super I/O chips', supporting floppy disks, infrared ports,
81joysticks and other miscellaneous stuff. For hardware monitoring, they
82include an 'environment controller' with 3 temperature sensors, 3 fan
83rotation speed sensors, 8 voltage sensors, and associated alarms.
84
85The IT8712F and IT8716F additionally feature VID inputs, used to report
86the Vcore voltage of the processor. The early IT8712F have 5 VID pins,
87the IT8716F and late IT8712F have 6. They are shared with other functions
88though, so the functionality may not be available on a given system.
89The driver dumbly assume it is there.
90
91The IT8718F and IT8720F also features VID inputs (up to 8 pins) but the value
92is stored in the Super-I/O configuration space. Due to technical limitations,
93this value can currently only be read once at initialization time, so
94the driver won't notice and report changes in the VID value. The two
95upper VID bits share their pins with voltage inputs (in5 and in6) so you
96can't have both on a given board.
97
98The IT8716F, IT8718F, IT8720F and later IT8712F revisions have support for
992 additional fans. The additional fans are supported by the driver.
100
101The IT8716F, IT8718F and IT8720F, and late IT8712F and IT8705F also have
102optional 16-bit tachometer counters for fans 1 to 3. This is better (no more
103fan clock divider mess) but not compatible with the older chips and
104revisions. The 16-bit tachometer mode is enabled by the driver when one
105of the above chips is detected.
106
107The IT8726F is just bit enhanced IT8716F with additional hardware
108for AMD power sequencing. Therefore the chip will appear as IT8716F
109to userspace applications.
110
111Temperatures are measured in degrees Celsius. An alarm is triggered once
112when the Overtemperature Shutdown limit is crossed.
113
114Fan rotation speeds are reported in RPM (rotations per minute). An alarm is
115triggered if the rotation speed has dropped below a programmable limit. When
11616-bit tachometer counters aren't used, fan readings can be divided by
117a programmable divider (1, 2, 4 or 8) to give the readings more range or
118accuracy. With a divider of 2, the lowest representable value is around
1192600 RPM. Not all RPM values can accurately be represented, so some rounding
120is done.
121
122Voltage sensors (also known as IN sensors) report their values in volts. An
123alarm is triggered if the voltage has crossed a programmable minimum or
124maximum limit. Note that minimum in this case always means 'closest to
125zero'; this is important for negative voltage measurements. All voltage
126inputs can measure voltages between 0 and 4.08 volts, with a resolution of
1270.016 volt. The battery voltage in8 does not have limit registers.
128
129The VID lines (IT8712F/IT8716F/IT8718F/IT8720F) encode the core voltage value:
130the voltage level your processor should work with. This is hardcoded by
131the mainboard and/or processor itself. It is a value in volts.
132
133If an alarm triggers, it will remain triggered until the hardware register
134is read at least once. This means that the cause for the alarm may already
135have disappeared! Note that in the current implementation, all hardware
136registers are read whenever any data is read (unless it is less than 1.5
137seconds since the last update). This means that you can easily miss
138once-only alarms.
139
140The IT87xx only updates its values each 1.5 seconds; reading it more often
141will do no harm, but will return 'old' values.
142
143To change sensor N to a thermistor, 'echo 4 > tempN_type' where N is 1, 2,
144or 3. To change sensor N to a thermal diode, 'echo 3 > tempN_type'.
145Give 0 for unused sensor. Any other value is invalid. To configure this at
146startup, consult lm_sensors's /etc/sensors.conf. (4 = thermistor;
1473 = thermal diode)
148
149
150Fan speed control
151-----------------
152
153The fan speed control features are limited to manual PWM mode. Automatic
154"Smart Guardian" mode control handling is not implemented. However
155if you want to go for "manual mode" just write 1 to pwmN_enable.
156
157If you are only able to control the fan speed with very small PWM values,
158try lowering the PWM base frequency (pwm1_freq). Depending on the fan,
159it may give you a somewhat greater control range. The same frequency is
160used to drive all fan outputs, which is why pwm2_freq and pwm3_freq are
161read-only.
162