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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
Jean Delvare44c1bcd2010-10-28 20:31:51 +020025 * IT8721F/IT8758E
26 Prefix: 'it8721'
27 Addresses scanned: from Super I/O config space (8 I/O ports)
28 Datasheet: Not publicly available
R.Marek@sh.cvut.cz7f15b662005-05-26 12:42:19 +000029 * SiS950 [clone of IT8705F]
Jean Delvare91749992005-10-08 00:10:00 +020030 Prefix: 'it87'
31 Addresses scanned: from Super I/O config space (8 I/O ports)
R.Marek@sh.cvut.cz7f15b662005-05-26 12:42:19 +000032 Datasheet: No longer be available
33
Jean Delvareb19367c2006-08-28 14:39:26 +020034Authors:
Jean Delvaref1d8e332007-11-25 16:14:44 +010035 Christophe Gauthron
Jean Delvareb19367c2006-08-28 14:39:26 +020036 Jean Delvare <khali@linux-fr.org>
R.Marek@sh.cvut.cz7f15b662005-05-26 12:42:19 +000037
38
39Module Parameters
40-----------------
41
42* update_vbat: int
43
44 0 if vbat should report power on value, 1 if vbat should be updated after
45 each read. Default is 0. On some boards the battery voltage is provided
46 by either the battery or the onboard power supply. Only the first reading
47 at power on will be the actual battery voltage (which the chip does
48 automatically). On other boards the battery voltage is always fed to
49 the chip so can be read at any time. Excessive reading may decrease
50 battery life but no information is given in the datasheet.
51
52* fix_pwm_polarity int
53
54 Force PWM polarity to active high (DANGEROUS). Some chips are
55 misconfigured by BIOS - PWM values would be inverted. This option tries
56 to fix this. Please contact your BIOS manufacturer and ask him for fix.
57
Jean Delvare8e9afcb2006-12-12 18:18:28 +010058
59Hardware Interfaces
60-------------------
61
62All the chips suported by this driver are LPC Super-I/O chips, accessed
63through the LPC bus (ISA-like I/O ports). The IT8712F additionally has an
64SMBus interface to the hardware monitoring functions. This driver no
65longer supports this interface though, as it is slower and less reliable
66than the ISA access, and was only available on a small number of
67motherboard models.
68
69
R.Marek@sh.cvut.cz7f15b662005-05-26 12:42:19 +000070Description
71-----------
72
Jean Delvare87673dd2006-08-28 14:37:19 +020073This driver implements support for the IT8705F, IT8712F, IT8716F,
Jean Delvare44c1bcd2010-10-28 20:31:51 +020074IT8718F, IT8720F, IT8721F, IT8726F, IT8758E and SiS950 chips.
R.Marek@sh.cvut.cz7f15b662005-05-26 12:42:19 +000075
76These chips are 'Super I/O chips', supporting floppy disks, infrared ports,
77joysticks and other miscellaneous stuff. For hardware monitoring, they
78include an 'environment controller' with 3 temperature sensors, 3 fan
79rotation speed sensors, 8 voltage sensors, and associated alarms.
80
Jean Delvare17d648b2006-08-28 14:23:46 +020081The IT8712F and IT8716F additionally feature VID inputs, used to report
82the Vcore voltage of the processor. The early IT8712F have 5 VID pins,
83the IT8716F and late IT8712F have 6. They are shared with other functions
84though, so the functionality may not be available on a given system.
Jean Delvare17d648b2006-08-28 14:23:46 +020085
Jean-Marc Spaggiarib4da93e2009-01-07 16:37:32 +010086The IT8718F and IT8720F also features VID inputs (up to 8 pins) but the value
87is stored in the Super-I/O configuration space. Due to technical limitations,
Jean Delvare87673dd2006-08-28 14:37:19 +020088this value can currently only be read once at initialization time, so
89the driver won't notice and report changes in the VID value. The two
90upper VID bits share their pins with voltage inputs (in5 and in6) so you
91can't have both on a given board.
Jean Delvare17d648b2006-08-28 14:23:46 +020092
Jean Delvare44c1bcd2010-10-28 20:31:51 +020093The IT8716F, IT8718F, IT8720F, IT8721F/IT8758E and later IT8712F revisions
94have support for 2 additional fans. The additional fans are supported by the
95driver.
Jean Delvare87673dd2006-08-28 14:37:19 +020096
Jean Delvare44c1bcd2010-10-28 20:31:51 +020097The IT8716F, IT8718F, IT8720F and IT8721F/IT8758E, and late IT8712F and
98IT8705F also have optional 16-bit tachometer counters for fans 1 to 3. This
99is better (no more fan clock divider mess) but not compatible with the older
100chips and revisions. The 16-bit tachometer mode is enabled by the driver when
101one of the above chips is detected.
Jean Delvare17d648b2006-08-28 14:23:46 +0200102
Rudolf Marek08a8f6e2007-06-09 10:11:16 -0400103The IT8726F is just bit enhanced IT8716F with additional hardware
104for AMD power sequencing. Therefore the chip will appear as IT8716F
105to userspace applications.
106
R.Marek@sh.cvut.cz7f15b662005-05-26 12:42:19 +0000107Temperatures are measured in degrees Celsius. An alarm is triggered once
108when the Overtemperature Shutdown limit is crossed.
109
110Fan rotation speeds are reported in RPM (rotations per minute). An alarm is
Jean Delvare17d648b2006-08-28 14:23:46 +0200111triggered if the rotation speed has dropped below a programmable limit. When
11216-bit tachometer counters aren't used, fan readings can be divided by
113a programmable divider (1, 2, 4 or 8) to give the readings more range or
114accuracy. With a divider of 2, the lowest representable value is around
1152600 RPM. Not all RPM values can accurately be represented, so some rounding
116is done.
R.Marek@sh.cvut.cz7f15b662005-05-26 12:42:19 +0000117
118Voltage sensors (also known as IN sensors) report their values in volts. An
119alarm is triggered if the voltage has crossed a programmable minimum or
120maximum limit. Note that minimum in this case always means 'closest to
121zero'; this is important for negative voltage measurements. All voltage
122inputs can measure voltages between 0 and 4.08 volts, with a resolution of
Jean Delvare44c1bcd2010-10-28 20:31:51 +02001230.016 volt (except IT8721F/IT8758E: 0.012 volt.) The battery voltage in8 does
124not have limit registers.
125
126On the IT8721F/IT8758E, some voltage inputs are internal and scaled inside
127the chip (in7, in8 and optionally in3). The driver handles this transparently
128so user-space doesn't have to care.
R.Marek@sh.cvut.cz7f15b662005-05-26 12:42:19 +0000129
Jean-Marc Spaggiarib4da93e2009-01-07 16:37:32 +0100130The VID lines (IT8712F/IT8716F/IT8718F/IT8720F) encode the core voltage value:
Jean Delvare87673dd2006-08-28 14:37:19 +0200131the voltage level your processor should work with. This is hardcoded by
132the mainboard and/or processor itself. It is a value in volts.
R.Marek@sh.cvut.cz7f15b662005-05-26 12:42:19 +0000133
134If an alarm triggers, it will remain triggered until the hardware register
135is read at least once. This means that the cause for the alarm may already
136have disappeared! Note that in the current implementation, all hardware
137registers are read whenever any data is read (unless it is less than 1.5
138seconds since the last update). This means that you can easily miss
139once-only alarms.
140
Jean Delvared9b327c2010-03-05 22:17:17 +0100141Out-of-limit readings can also result in beeping, if the chip is properly
142wired and configured. Beeping can be enabled or disabled per sensor type
143(temperatures, voltages and fans.)
144
R.Marek@sh.cvut.cz7f15b662005-05-26 12:42:19 +0000145The IT87xx only updates its values each 1.5 seconds; reading it more often
146will do no harm, but will return 'old' values.
147
Jean Delvare4ed10772008-10-17 17:51:16 +0200148To 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 +0000149or 3. To change sensor N to a thermal diode, 'echo 3 > tempN_type'.
150Give 0 for unused sensor. Any other value is invalid. To configure this at
Jean Delvare4ed10772008-10-17 17:51:16 +0200151startup, consult lm_sensors's /etc/sensors.conf. (4 = thermistor;
R.Marek@sh.cvut.cz7f15b662005-05-26 12:42:19 +00001523 = thermal diode)
153
Jean Delvaref8d0c192007-02-14 21:15:02 +0100154
155Fan speed control
156-----------------
157
R.Marek@sh.cvut.cz7f15b662005-05-26 12:42:19 +0000158The fan speed control features are limited to manual PWM mode. Automatic
Jean Delvare4f3f51b2010-03-05 22:17:21 +0100159"Smart Guardian" mode control handling is only implemented for older chips
160(see below.) However if you want to go for "manual mode" just write 1 to
161pwmN_enable.
Jean Delvaref8d0c192007-02-14 21:15:02 +0100162
163If you are only able to control the fan speed with very small PWM values,
164try lowering the PWM base frequency (pwm1_freq). Depending on the fan,
165it may give you a somewhat greater control range. The same frequency is
166used to drive all fan outputs, which is why pwm2_freq and pwm3_freq are
167read-only.
Jean Delvare4f3f51b2010-03-05 22:17:21 +0100168
169
170Automatic fan speed control (old interface)
171-------------------------------------------
172
173The driver supports the old interface to automatic fan speed control
174which is implemented by IT8705F chips up to revision F and IT8712F
175chips up to revision G.
176
177This interface implements 4 temperature vs. PWM output trip points.
178The PWM output of trip point 4 is always the maximum value (fan running
179at full speed) while the PWM output of the other 3 trip points can be
180freely chosen. The temperature of all 4 trip points can be freely chosen.
181Additionally, trip point 1 has an hysteresis temperature attached, to
182prevent fast switching between fan on and off.
183
184The chip automatically computes the PWM output value based on the input
185temperature, based on this simple rule: if the temperature value is
186between trip point N and trip point N+1 then the PWM output value is
187the one of trip point N. The automatic control mode is less flexible
188than the manual control mode, but it reacts faster, is more robust and
189doesn't use CPU cycles.
Jean Delvarecccfc9c2010-03-05 22:17:21 +0100190
191Trip points must be set properly before switching to automatic fan speed
192control mode. The driver will perform basic integrity checks before
193actually switching to automatic control mode.