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7f15b664 RM |
1 | Kernel driver it87 |
2 | ================== | |
3 | ||
4 | Supported chips: | |
5 | * IT8705F | |
6 | Prefix: 'it87' | |
91749996 | 7 | Addresses scanned: from Super I/O config space (8 I/O ports) |
404a552d | 8 | Datasheet: Once publicly available at the ITE website, but no longer |
7f15b664 RM |
9 | * IT8712F |
10 | Prefix: 'it8712' | |
8e9afcbb | 11 | Addresses scanned: from Super I/O config space (8 I/O ports) |
404a552d | 12 | Datasheet: Once publicly available at the ITE website, but no longer |
08a8f6e9 | 13 | * IT8716F/IT8726F |
17d648bf JD |
14 | Prefix: 'it8716' |
15 | Addresses scanned: from Super I/O config space (8 I/O ports) | |
404a552d | 16 | Datasheet: Once publicly available at the ITE website, but no longer |
87673dd7 JD |
17 | * IT8718F |
18 | Prefix: 'it8718' | |
19 | Addresses scanned: from Super I/O config space (8 I/O ports) | |
404a552d | 20 | Datasheet: Once publicly available at the ITE website, but no longer |
b4da93e4 JMS |
21 | * IT8720F |
22 | Prefix: 'it8720' | |
23 | Addresses scanned: from Super I/O config space (8 I/O ports) | |
404a552d | 24 | Datasheet: Not publicly available |
7f15b664 | 25 | * SiS950 [clone of IT8705F] |
91749996 JD |
26 | Prefix: 'it87' |
27 | Addresses scanned: from Super I/O config space (8 I/O ports) | |
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28 | Datasheet: No longer be available |
29 | ||
b19367c6 | 30 | Authors: |
f1d8e332 | 31 | Christophe Gauthron |
b19367c6 | 32 | Jean Delvare <khali@linux-fr.org> |
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33 | |
34 | ||
35 | Module 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 | ||
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54 | |
55 | Hardware Interfaces | |
56 | ------------------- | |
57 | ||
58 | All the chips suported by this driver are LPC Super-I/O chips, accessed | |
59 | through the LPC bus (ISA-like I/O ports). The IT8712F additionally has an | |
60 | SMBus interface to the hardware monitoring functions. This driver no | |
61 | longer supports this interface though, as it is slower and less reliable | |
62 | than the ISA access, and was only available on a small number of | |
63 | motherboard models. | |
64 | ||
65 | ||
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66 | Description |
67 | ----------- | |
68 | ||
87673dd7 | 69 | This driver implements support for the IT8705F, IT8712F, IT8716F, |
b4da93e4 | 70 | IT8718F, IT8720F, IT8726F and SiS950 chips. |
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71 | |
72 | These chips are 'Super I/O chips', supporting floppy disks, infrared ports, | |
73 | joysticks and other miscellaneous stuff. For hardware monitoring, they | |
74 | include an 'environment controller' with 3 temperature sensors, 3 fan | |
75 | rotation speed sensors, 8 voltage sensors, and associated alarms. | |
76 | ||
17d648bf JD |
77 | The IT8712F and IT8716F additionally feature VID inputs, used to report |
78 | the Vcore voltage of the processor. The early IT8712F have 5 VID pins, | |
79 | the IT8716F and late IT8712F have 6. They are shared with other functions | |
80 | though, so the functionality may not be available on a given system. | |
17d648bf | 81 | |
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82 | The IT8718F and IT8720F also features VID inputs (up to 8 pins) but the value |
83 | is stored in the Super-I/O configuration space. Due to technical limitations, | |
87673dd7 JD |
84 | this value can currently only be read once at initialization time, so |
85 | the driver won't notice and report changes in the VID value. The two | |
86 | upper VID bits share their pins with voltage inputs (in5 and in6) so you | |
87 | can't have both on a given board. | |
88 | ||
b4da93e4 | 89 | The IT8716F, IT8718F, IT8720F and later IT8712F revisions have support for |
0475169c | 90 | 2 additional fans. The additional fans are supported by the driver. |
17d648bf | 91 | |
b4da93e4 JMS |
92 | The IT8716F, IT8718F and IT8720F, and late IT8712F and IT8705F also have |
93 | optional 16-bit tachometer counters for fans 1 to 3. This is better (no more | |
94 | fan clock divider mess) but not compatible with the older chips and | |
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95 | revisions. The 16-bit tachometer mode is enabled by the driver when one |
96 | of the above chips is detected. | |
17d648bf | 97 | |
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98 | The IT8726F is just bit enhanced IT8716F with additional hardware |
99 | for AMD power sequencing. Therefore the chip will appear as IT8716F | |
100 | to userspace applications. | |
101 | ||
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102 | Temperatures are measured in degrees Celsius. An alarm is triggered once |
103 | when the Overtemperature Shutdown limit is crossed. | |
104 | ||
105 | Fan rotation speeds are reported in RPM (rotations per minute). An alarm is | |
17d648bf JD |
106 | triggered if the rotation speed has dropped below a programmable limit. When |
107 | 16-bit tachometer counters aren't used, fan readings can be divided by | |
108 | a programmable divider (1, 2, 4 or 8) to give the readings more range or | |
109 | accuracy. With a divider of 2, the lowest representable value is around | |
110 | 2600 RPM. Not all RPM values can accurately be represented, so some rounding | |
111 | is done. | |
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112 | |
113 | Voltage sensors (also known as IN sensors) report their values in volts. An | |
114 | alarm is triggered if the voltage has crossed a programmable minimum or | |
115 | maximum limit. Note that minimum in this case always means 'closest to | |
116 | zero'; this is important for negative voltage measurements. All voltage | |
117 | inputs can measure voltages between 0 and 4.08 volts, with a resolution of | |
118 | 0.016 volt. The battery voltage in8 does not have limit registers. | |
119 | ||
b4da93e4 | 120 | The VID lines (IT8712F/IT8716F/IT8718F/IT8720F) encode the core voltage value: |
87673dd7 JD |
121 | the voltage level your processor should work with. This is hardcoded by |
122 | the mainboard and/or processor itself. It is a value in volts. | |
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123 | |
124 | If an alarm triggers, it will remain triggered until the hardware register | |
125 | is read at least once. This means that the cause for the alarm may already | |
126 | have disappeared! Note that in the current implementation, all hardware | |
127 | registers are read whenever any data is read (unless it is less than 1.5 | |
128 | seconds since the last update). This means that you can easily miss | |
129 | once-only alarms. | |
130 | ||
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131 | Out-of-limit readings can also result in beeping, if the chip is properly |
132 | wired and configured. Beeping can be enabled or disabled per sensor type | |
133 | (temperatures, voltages and fans.) | |
134 | ||
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135 | The IT87xx only updates its values each 1.5 seconds; reading it more often |
136 | will do no harm, but will return 'old' values. | |
137 | ||
4ed10779 | 138 | To change sensor N to a thermistor, 'echo 4 > tempN_type' where N is 1, 2, |
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139 | or 3. To change sensor N to a thermal diode, 'echo 3 > tempN_type'. |
140 | Give 0 for unused sensor. Any other value is invalid. To configure this at | |
4ed10779 | 141 | startup, consult lm_sensors's /etc/sensors.conf. (4 = thermistor; |
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142 | 3 = thermal diode) |
143 | ||
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144 | |
145 | Fan speed control | |
146 | ----------------- | |
147 | ||
7f15b664 | 148 | The fan speed control features are limited to manual PWM mode. Automatic |
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149 | "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 | |
151 | pwmN_enable. | |
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152 | |
153 | If you are only able to control the fan speed with very small PWM values, | |
154 | try lowering the PWM base frequency (pwm1_freq). Depending on the fan, | |
155 | it may give you a somewhat greater control range. The same frequency is | |
156 | used to drive all fan outputs, which is why pwm2_freq and pwm3_freq are | |
157 | read-only. | |
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158 | |
159 | ||
160 | Automatic fan speed control (old interface) | |
161 | ------------------------------------------- | |
162 | ||
163 | The driver supports the old interface to automatic fan speed control | |
164 | which is implemented by IT8705F chips up to revision F and IT8712F | |
165 | chips up to revision G. | |
166 | ||
167 | This interface implements 4 temperature vs. PWM output trip points. | |
168 | The PWM output of trip point 4 is always the maximum value (fan running | |
169 | at full speed) while the PWM output of the other 3 trip points can be | |
170 | freely chosen. The temperature of all 4 trip points can be freely chosen. | |
171 | Additionally, trip point 1 has an hysteresis temperature attached, to | |
172 | prevent fast switching between fan on and off. | |
173 | ||
174 | The chip automatically computes the PWM output value based on the input | |
175 | temperature, based on this simple rule: if the temperature value is | |
176 | between trip point N and trip point N+1 then the PWM output value is | |
177 | the one of trip point N. The automatic control mode is less flexible | |
178 | than the manual control mode, but it reacts faster, is more robust and | |
179 | doesn't use CPU cycles. |