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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: 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 * IT8782F
34 Prefix: 'it8782'
35 Addresses scanned: from Super I/O config space (8 I/O ports)
36 Datasheet: Not publicly available
37 * IT8783E/F
38 Prefix: 'it8783'
39 Addresses scanned: from Super I/O config space (8 I/O ports)
40 Datasheet: Not publicly available
41 * SiS950 [clone of IT8705F]
42 Prefix: 'it87'
43 Addresses scanned: from Super I/O config space (8 I/O ports)
44 Datasheet: No longer be available
45
46Authors:
47 Christophe Gauthron
48 Jean Delvare <khali@linux-fr.org>
49
50
51Module Parameters
52-----------------
53
54* update_vbat: int
55
56 0 if vbat should report power on value, 1 if vbat should be updated after
57 each read. Default is 0. On some boards the battery voltage is provided
58 by either the battery or the onboard power supply. Only the first reading
59 at power on will be the actual battery voltage (which the chip does
60 automatically). On other boards the battery voltage is always fed to
61 the chip so can be read at any time. Excessive reading may decrease
62 battery life but no information is given in the datasheet.
63
64* fix_pwm_polarity int
65
66 Force PWM polarity to active high (DANGEROUS). Some chips are
67 misconfigured by BIOS - PWM values would be inverted. This option tries
68 to fix this. Please contact your BIOS manufacturer and ask him for fix.
69
70
71Hardware Interfaces
72-------------------
73
74All the chips supported by this driver are LPC Super-I/O chips, accessed
75through the LPC bus (ISA-like I/O ports). The IT8712F additionally has an
76SMBus interface to the hardware monitoring functions. This driver no
77longer supports this interface though, as it is slower and less reliable
78than the ISA access, and was only available on a small number of
79motherboard models.
80
81
82Description
83-----------
84
85This driver implements support for the IT8705F, IT8712F, IT8716F,
86IT8718F, IT8720F, IT8721F, IT8726F, IT8728F, IT8758E, IT8781F, IT8782F,
87IT8783E/F, and SiS950 chips.
88
89These chips are 'Super I/O chips', supporting floppy disks, infrared ports,
90joysticks and other miscellaneous stuff. For hardware monitoring, they
91include an 'environment controller' with 3 temperature sensors, 3 fan
92rotation speed sensors, 8 voltage sensors, associated alarms, and chassis
93intrusion detection.
94
95The IT8712F and IT8716F additionally feature VID inputs, used to report
96the Vcore voltage of the processor. The early IT8712F have 5 VID pins,
97the IT8716F and late IT8712F have 6. They are shared with other functions
98though, so the functionality may not be available on a given system.
99
100The IT8718F and IT8720F also features VID inputs (up to 8 pins) but the value
101is stored in the Super-I/O configuration space. Due to technical limitations,
102this value can currently only be read once at initialization time, so
103the driver won't notice and report changes in the VID value. The two
104upper VID bits share their pins with voltage inputs (in5 and in6) so you
105can't have both on a given board.
106
107The IT8716F, IT8718F, IT8720F, IT8721F/IT8758E and later IT8712F revisions
108have support for 2 additional fans. The additional fans are supported by the
109driver.
110
111The IT8716F, IT8718F, IT8720F, IT8721F/IT8758E, IT8782F, IT8783E/F, and late
112IT8712F and IT8705F also have optional 16-bit tachometer counters for fans 1 to
1133. This is better (no more fan clock divider mess) but not compatible with the
114older chips and revisions. The 16-bit tachometer mode is enabled by the driver
115when one of the above chips is detected.
116
117The IT8726F is just bit enhanced IT8716F with additional hardware
118for AMD power sequencing. Therefore the chip will appear as IT8716F
119to userspace applications.
120
121The IT8728F is considered compatible with the IT8721F, until a datasheet
122becomes available (hopefully.)
123
124Temperatures are measured in degrees Celsius. An alarm is triggered once
125when the Overtemperature Shutdown limit is crossed.
126
127Fan rotation speeds are reported in RPM (rotations per minute). An alarm is
128triggered if the rotation speed has dropped below a programmable limit. When
12916-bit tachometer counters aren't used, fan readings can be divided by
130a programmable divider (1, 2, 4 or 8) to give the readings more range or
131accuracy. With a divider of 2, the lowest representable value is around
1322600 RPM. Not all RPM values can accurately be represented, so some rounding
133is done.
134
135Voltage sensors (also known as IN sensors) report their values in volts. An
136alarm is triggered if the voltage has crossed a programmable minimum or
137maximum limit. Note that minimum in this case always means 'closest to
138zero'; this is important for negative voltage measurements. All voltage
139inputs can measure voltages between 0 and 4.08 volts, with a resolution of
1400.016 volt (except IT8721F/IT8758E and IT8728F: 0.012 volt.) The battery
141voltage in8 does not have limit registers.
142
143On the IT8721F/IT8758E, IT8782F, and IT8783E/F, some voltage inputs are
144internal and scaled inside the chip (in7 (optional for IT8782F and IT8783E/F),
145in8 and optionally in3). The driver handles this transparently so user-space
146doesn't have to care.
147
148The VID lines (IT8712F/IT8716F/IT8718F/IT8720F) encode the core voltage value:
149the voltage level your processor should work with. This is hardcoded by
150the mainboard and/or processor itself. It is a value in volts.
151
152If an alarm triggers, it will remain triggered until the hardware register
153is read at least once. This means that the cause for the alarm may already
154have disappeared! Note that in the current implementation, all hardware
155registers are read whenever any data is read (unless it is less than 1.5
156seconds since the last update). This means that you can easily miss
157once-only alarms.
158
159Out-of-limit readings can also result in beeping, if the chip is properly
160wired and configured. Beeping can be enabled or disabled per sensor type
161(temperatures, voltages and fans.)
162
163The IT87xx only updates its values each 1.5 seconds; reading it more often
164will do no harm, but will return 'old' values.
165
166To change sensor N to a thermistor, 'echo 4 > tempN_type' where N is 1, 2,
167or 3. To change sensor N to a thermal diode, 'echo 3 > tempN_type'.
168Give 0 for unused sensor. Any other value is invalid. To configure this at
169startup, consult lm_sensors's /etc/sensors.conf. (4 = thermistor;
1703 = thermal diode)
171
172
173Fan speed control
174-----------------
175
176The fan speed control features are limited to manual PWM mode. Automatic
177"Smart Guardian" mode control handling is only implemented for older chips
178(see below.) However if you want to go for "manual mode" just write 1 to
179pwmN_enable.
180
181If you are only able to control the fan speed with very small PWM values,
182try lowering the PWM base frequency (pwm1_freq). Depending on the fan,
183it may give you a somewhat greater control range. The same frequency is
184used to drive all fan outputs, which is why pwm2_freq and pwm3_freq are
185read-only.
186
187
188Automatic fan speed control (old interface)
189-------------------------------------------
190
191The driver supports the old interface to automatic fan speed control
192which is implemented by IT8705F chips up to revision F and IT8712F
193chips up to revision G.
194
195This interface implements 4 temperature vs. PWM output trip points.
196The PWM output of trip point 4 is always the maximum value (fan running
197at full speed) while the PWM output of the other 3 trip points can be
198freely chosen. The temperature of all 4 trip points can be freely chosen.
199Additionally, trip point 1 has an hysteresis temperature attached, to
200prevent fast switching between fan on and off.
201
202The chip automatically computes the PWM output value based on the input
203temperature, based on this simple rule: if the temperature value is
204between trip point N and trip point N+1 then the PWM output value is
205the one of trip point N. The automatic control mode is less flexible
206than the manual control mode, but it reacts faster, is more robust and
207doesn't use CPU cycles.
208
209Trip points must be set properly before switching to automatic fan speed
210control mode. The driver will perform basic integrity checks before
211actually switching to automatic control mode.