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7f15b664 M |
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 M |
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 |
44c1bcd4 JD |
25 | * IT8721F/IT8758E |
26 | Prefix: 'it8721' | |
27 | Addresses scanned: from Super I/O config space (8 I/O ports) | |
28 | Datasheet: Not publicly available | |
7f15b664 | 29 | * SiS950 [clone of IT8705F] |
91749996 JD |
30 | Prefix: 'it87' |
31 | Addresses scanned: from Super I/O config space (8 I/O ports) | |
7f15b664 M |
32 | Datasheet: No longer be available |
33 | ||
b19367c6 | 34 | Authors: |
f1d8e332 | 35 | Christophe Gauthron |
b19367c6 | 36 | Jean Delvare <khali@linux-fr.org> |
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37 | |
38 | ||
39 | Module 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 | ||
8e9afcbb JD |
58 | |
59 | Hardware Interfaces | |
60 | ------------------- | |
61 | ||
62 | All the chips suported by this driver are LPC Super-I/O chips, accessed | |
63 | through the LPC bus (ISA-like I/O ports). The IT8712F additionally has an | |
64 | SMBus interface to the hardware monitoring functions. This driver no | |
65 | longer supports this interface though, as it is slower and less reliable | |
66 | than the ISA access, and was only available on a small number of | |
67 | motherboard models. | |
68 | ||
69 | ||
7f15b664 M |
70 | Description |
71 | ----------- | |
72 | ||
87673dd7 | 73 | This driver implements support for the IT8705F, IT8712F, IT8716F, |
44c1bcd4 | 74 | IT8718F, IT8720F, IT8721F, IT8726F, IT8758E and SiS950 chips. |
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75 | |
76 | These chips are 'Super I/O chips', supporting floppy disks, infrared ports, | |
77 | joysticks and other miscellaneous stuff. For hardware monitoring, they | |
78 | include an 'environment controller' with 3 temperature sensors, 3 fan | |
3d30f9e6 JD |
79 | rotation speed sensors, 8 voltage sensors, associated alarms, and chassis |
80 | intrusion detection. | |
7f15b664 | 81 | |
17d648bf JD |
82 | The IT8712F and IT8716F additionally feature VID inputs, used to report |
83 | the Vcore voltage of the processor. The early IT8712F have 5 VID pins, | |
84 | the IT8716F and late IT8712F have 6. They are shared with other functions | |
85 | though, so the functionality may not be available on a given system. | |
17d648bf | 86 | |
b4da93e4 JMS |
87 | The IT8718F and IT8720F also features VID inputs (up to 8 pins) but the value |
88 | is stored in the Super-I/O configuration space. Due to technical limitations, | |
87673dd7 JD |
89 | this value can currently only be read once at initialization time, so |
90 | the driver won't notice and report changes in the VID value. The two | |
91 | upper VID bits share their pins with voltage inputs (in5 and in6) so you | |
92 | can't have both on a given board. | |
93 | ||
44c1bcd4 JD |
94 | The IT8716F, IT8718F, IT8720F, IT8721F/IT8758E and later IT8712F revisions |
95 | have support for 2 additional fans. The additional fans are supported by the | |
96 | driver. | |
17d648bf | 97 | |
44c1bcd4 JD |
98 | The IT8716F, IT8718F, IT8720F and IT8721F/IT8758E, and late IT8712F and |
99 | IT8705F also have optional 16-bit tachometer counters for fans 1 to 3. This | |
100 | is better (no more fan clock divider mess) but not compatible with the older | |
101 | chips and revisions. The 16-bit tachometer mode is enabled by the driver when | |
102 | one of the above chips is detected. | |
17d648bf | 103 | |
08a8f6e9 RM |
104 | The IT8726F is just bit enhanced IT8716F with additional hardware |
105 | for AMD power sequencing. Therefore the chip will appear as IT8716F | |
106 | to userspace applications. | |
107 | ||
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108 | Temperatures are measured in degrees Celsius. An alarm is triggered once |
109 | when the Overtemperature Shutdown limit is crossed. | |
110 | ||
111 | Fan rotation speeds are reported in RPM (rotations per minute). An alarm is | |
17d648bf JD |
112 | triggered if the rotation speed has dropped below a programmable limit. When |
113 | 16-bit tachometer counters aren't used, fan readings can be divided by | |
114 | a programmable divider (1, 2, 4 or 8) to give the readings more range or | |
115 | accuracy. With a divider of 2, the lowest representable value is around | |
116 | 2600 RPM. Not all RPM values can accurately be represented, so some rounding | |
117 | is done. | |
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118 | |
119 | Voltage sensors (also known as IN sensors) report their values in volts. An | |
120 | alarm is triggered if the voltage has crossed a programmable minimum or | |
121 | maximum limit. Note that minimum in this case always means 'closest to | |
122 | zero'; this is important for negative voltage measurements. All voltage | |
123 | inputs can measure voltages between 0 and 4.08 volts, with a resolution of | |
44c1bcd4 JD |
124 | 0.016 volt (except IT8721F/IT8758E: 0.012 volt.) The battery voltage in8 does |
125 | not have limit registers. | |
126 | ||
127 | On the IT8721F/IT8758E, some voltage inputs are internal and scaled inside | |
128 | the chip (in7, in8 and optionally in3). The driver handles this transparently | |
129 | so user-space doesn't have to care. | |
7f15b664 | 130 | |
b4da93e4 | 131 | The VID lines (IT8712F/IT8716F/IT8718F/IT8720F) encode the core voltage value: |
87673dd7 JD |
132 | the voltage level your processor should work with. This is hardcoded by |
133 | the mainboard and/or processor itself. It is a value in volts. | |
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134 | |
135 | If an alarm triggers, it will remain triggered until the hardware register | |
136 | is read at least once. This means that the cause for the alarm may already | |
137 | have disappeared! Note that in the current implementation, all hardware | |
138 | registers are read whenever any data is read (unless it is less than 1.5 | |
139 | seconds since the last update). This means that you can easily miss | |
140 | once-only alarms. | |
141 | ||
d9b327c3 JD |
142 | Out-of-limit readings can also result in beeping, if the chip is properly |
143 | wired and configured. Beeping can be enabled or disabled per sensor type | |
144 | (temperatures, voltages and fans.) | |
145 | ||
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146 | The IT87xx only updates its values each 1.5 seconds; reading it more often |
147 | will do no harm, but will return 'old' values. | |
148 | ||
4ed10779 | 149 | To change sensor N to a thermistor, 'echo 4 > tempN_type' where N is 1, 2, |
7f15b664 M |
150 | or 3. To change sensor N to a thermal diode, 'echo 3 > tempN_type'. |
151 | Give 0 for unused sensor. Any other value is invalid. To configure this at | |
4ed10779 | 152 | startup, consult lm_sensors's /etc/sensors.conf. (4 = thermistor; |
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153 | 3 = thermal diode) |
154 | ||
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155 | |
156 | Fan speed control | |
157 | ----------------- | |
158 | ||
7f15b664 | 159 | The fan speed control features are limited to manual PWM mode. Automatic |
4f3f51bc JD |
160 | "Smart Guardian" mode control handling is only implemented for older chips |
161 | (see below.) However if you want to go for "manual mode" just write 1 to | |
162 | pwmN_enable. | |
f8d0c19a JD |
163 | |
164 | If you are only able to control the fan speed with very small PWM values, | |
165 | try lowering the PWM base frequency (pwm1_freq). Depending on the fan, | |
166 | it may give you a somewhat greater control range. The same frequency is | |
167 | used to drive all fan outputs, which is why pwm2_freq and pwm3_freq are | |
168 | read-only. | |
4f3f51bc JD |
169 | |
170 | ||
171 | Automatic fan speed control (old interface) | |
172 | ------------------------------------------- | |
173 | ||
174 | The driver supports the old interface to automatic fan speed control | |
175 | which is implemented by IT8705F chips up to revision F and IT8712F | |
176 | chips up to revision G. | |
177 | ||
178 | This interface implements 4 temperature vs. PWM output trip points. | |
179 | The PWM output of trip point 4 is always the maximum value (fan running | |
180 | at full speed) while the PWM output of the other 3 trip points can be | |
181 | freely chosen. The temperature of all 4 trip points can be freely chosen. | |
182 | Additionally, trip point 1 has an hysteresis temperature attached, to | |
183 | prevent fast switching between fan on and off. | |
184 | ||
185 | The chip automatically computes the PWM output value based on the input | |
186 | temperature, based on this simple rule: if the temperature value is | |
187 | between trip point N and trip point N+1 then the PWM output value is | |
188 | the one of trip point N. The automatic control mode is less flexible | |
189 | than the manual control mode, but it reacts faster, is more robust and | |
190 | doesn't use CPU cycles. | |
cccfc9c4 JD |
191 | |
192 | Trip points must be set properly before switching to automatic fan speed | |
193 | control mode. The driver will perform basic integrity checks before | |
194 | actually switching to automatic control mode. |