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61d0b533 JH |
1 | Kernel driver vt1211 |
2 | ==================== | |
3 | ||
4 | Supported chips: | |
cdc39b09 | 5 | |
61d0b533 | 6 | * VIA VT1211 |
cdc39b09 | 7 | |
61d0b533 | 8 | Prefix: 'vt1211' |
cdc39b09 | 9 | |
61d0b533 | 10 | Addresses scanned: none, address read from Super-I/O config space |
cdc39b09 | 11 | |
61d0b533 JH |
12 | Datasheet: Provided by VIA upon request and under NDA |
13 | ||
14 | Authors: Juerg Haefliger <juergh@gmail.com> | |
15 | ||
16 | This driver is based on the driver for kernel 2.4 by Mark D. Studebaker and | |
17 | its port to kernel 2.6 by Lars Ekman. | |
18 | ||
19 | Thanks to Joseph Chan and Fiona Gatt from VIA for providing documentation and | |
20 | technical support. | |
21 | ||
22 | ||
a1fdcb96 JH |
23 | Module Parameters |
24 | ----------------- | |
25 | ||
cdc39b09 MCC |
26 | |
27 | * uch_config: int | |
28 | Override the BIOS default universal channel (UCH) | |
a1fdcb96 JH |
29 | configuration for channels 1-5. |
30 | Legal values are in the range of 0-31. Bit 0 maps to | |
31 | UCH1, bit 1 maps to UCH2 and so on. Setting a bit to 1 | |
32 | enables the thermal input of that particular UCH and | |
33 | setting a bit to 0 enables the voltage input. | |
34 | ||
cdc39b09 MCC |
35 | * int_mode: int |
36 | Override the BIOS default temperature interrupt mode. | |
a1fdcb96 JH |
37 | The only possible value is 0 which forces interrupt |
38 | mode 0. In this mode, any pending interrupt is cleared | |
39 | when the status register is read but is regenerated as | |
40 | long as the temperature stays above the hysteresis | |
41 | limit. | |
42 | ||
43 | Be aware that overriding BIOS defaults might cause some unwanted side effects! | |
44 | ||
45 | ||
61d0b533 JH |
46 | Description |
47 | ----------- | |
48 | ||
49 | The VIA VT1211 Super-I/O chip includes complete hardware monitoring | |
50 | capabilities. It monitors 2 dedicated temperature sensor inputs (temp1 and | |
51 | temp2), 1 dedicated voltage (in5) and 2 fans. Additionally, the chip | |
52 | implements 5 universal input channels (UCH1-5) that can be individually | |
53 | programmed to either monitor a voltage or a temperature. | |
54 | ||
55 | This chip also provides manual and automatic control of fan speeds (according | |
56 | to the datasheet). The driver only supports automatic control since the manual | |
57 | mode doesn't seem to work as advertised in the datasheet. In fact I couldn't | |
58 | get manual mode to work at all! Be aware that automatic mode hasn't been | |
59 | tested very well (due to the fact that my EPIA M10000 doesn't have the fans | |
60 | connected to the PWM outputs of the VT1211 :-(). | |
61 | ||
62 | The following table shows the relationship between the vt1211 inputs and the | |
63 | sysfs nodes. | |
64 | ||
cdc39b09 | 65 | =============== ============== =========== ================================ |
61d0b533 | 66 | Sensor Voltage Mode Temp Mode Default Use (from the datasheet) |
cdc39b09 | 67 | =============== ============== =========== ================================ |
61d0b533 JH |
68 | Reading 1 temp1 Intel thermal diode |
69 | Reading 3 temp2 Internal thermal diode | |
70 | UCH1/Reading2 in0 temp3 NTC type thermistor | |
71 | UCH2 in1 temp4 +2.5V | |
72 | UCH3 in2 temp5 VccP (processor core) | |
73 | UCH4 in3 temp6 +5V | |
74 | UCH5 in4 temp7 +12V | |
75 | +3.3V in5 Internal VCC (+3.3V) | |
cdc39b09 | 76 | =============== ============== =========== ================================ |
61d0b533 JH |
77 | |
78 | ||
79 | Voltage Monitoring | |
80 | ------------------ | |
81 | ||
82 | Voltages are sampled by an 8-bit ADC with a LSB of ~10mV. The supported input | |
83 | range is thus from 0 to 2.60V. Voltage values outside of this range need | |
84 | external scaling resistors. This external scaling needs to be compensated for | |
85 | via compute lines in sensors.conf, like: | |
86 | ||
87 | compute inx @*(1+R1/R2), @/(1+R1/R2) | |
88 | ||
89 | The board level scaling resistors according to VIA's recommendation are as | |
90 | follows. And this is of course totally dependent on the actual board | |
91 | implementation :-) You will have to find documentation for your own | |
92 | motherboard and edit sensors.conf accordingly. | |
93 | ||
cdc39b09 MCC |
94 | ============= ====== ====== ========= ============ |
95 | Expected | |
61d0b533 | 96 | Voltage R1 R2 Divider Raw Value |
cdc39b09 | 97 | ============= ====== ====== ========= ============ |
61d0b533 | 98 | +2.5V 2K 10K 1.2 2083 mV |
cdc39b09 | 99 | VccP --- --- 1.0 1400 mV [1]_ |
61d0b533 JH |
100 | +5V 14K 10K 2.4 2083 mV |
101 | +12V 47K 10K 5.7 2105 mV | |
cdc39b09 | 102 | +3.3V (int) 2K 3.4K 1.588 3300 mV [2]_ |
61d0b533 | 103 | +3.3V (ext) 6.8K 10K 1.68 1964 mV |
cdc39b09 MCC |
104 | ============= ====== ====== ========= ============ |
105 | ||
106 | .. [1] Depending on the CPU (1.4V is for a VIA C3 Nehemiah). | |
61d0b533 | 107 | |
cdc39b09 MCC |
108 | .. [2] R1 and R2 for 3.3V (int) are internal to the VT1211 chip and the driver |
109 | performs the scaling and returns the properly scaled voltage value. | |
61d0b533 JH |
110 | |
111 | Each measured voltage has an associated low and high limit which triggers an | |
112 | alarm when crossed. | |
113 | ||
114 | ||
115 | Temperature Monitoring | |
116 | ---------------------- | |
117 | ||
118 | Temperatures are reported in millidegree Celsius. Each measured temperature | |
119 | has a high limit which triggers an alarm if crossed. There is an associated | |
120 | hysteresis value with each temperature below which the temperature has to drop | |
121 | before the alarm is cleared (this is only true for interrupt mode 0). The | |
122 | interrupt mode can be forced to 0 in case the BIOS doesn't do it | |
a1fdcb96 | 123 | automatically. See the 'Module Parameters' section for details. |
61d0b533 JH |
124 | |
125 | All temperature channels except temp2 are external. Temp2 is the VT1211 | |
126 | internal thermal diode and the driver does all the scaling for temp2 and | |
127 | returns the temperature in millidegree Celsius. For the external channels | |
128 | temp1 and temp3-temp7, scaling depends on the board implementation and needs | |
129 | to be performed in userspace via sensors.conf. | |
130 | ||
131 | Temp1 is an Intel-type thermal diode which requires the following formula to | |
132 | convert between sysfs readings and real temperatures: | |
133 | ||
134 | compute temp1 (@-Offset)/Gain, (@*Gain)+Offset | |
135 | ||
136 | According to the VIA VT1211 BIOS porting guide, the following gain and offset | |
137 | values should be used: | |
138 | ||
cdc39b09 | 139 | =============== ======== =========== |
61d0b533 | 140 | Diode Type Offset Gain |
cdc39b09 | 141 | =============== ======== =========== |
61d0b533 | 142 | Intel CPU 88.638 0.9528 |
cdc39b09 | 143 | 65.000 0.9686 [3]_ |
61d0b533 JH |
144 | VIA C3 Ezra 83.869 0.9528 |
145 | VIA C3 Ezra-T 73.869 0.9528 | |
cdc39b09 | 146 | =============== ======== =========== |
61d0b533 | 147 | |
cdc39b09 MCC |
148 | .. [3] This is the formula from the lm_sensors 2.10.0 sensors.conf file. I don't |
149 | know where it comes from or how it was derived, it's just listed here for | |
150 | completeness. | |
61d0b533 JH |
151 | |
152 | Temp3-temp7 support NTC thermistors. For these channels, the driver returns | |
153 | the voltages as seen at the individual pins of UCH1-UCH5. The voltage at the | |
154 | pin (Vpin) is formed by a voltage divider made of the thermistor (Rth) and a | |
cdc39b09 | 155 | scaling resistor (Rs):: |
61d0b533 | 156 | |
cdc39b09 | 157 | Vpin = 2200 * Rth / (Rs + Rth) (2200 is the ADC max limit of 2200 mV) |
61d0b533 JH |
158 | |
159 | The equation for the thermistor is as follows (google it if you want to know | |
cdc39b09 | 160 | more about it):: |
61d0b533 | 161 | |
cdc39b09 MCC |
162 | Rth = Ro * exp(B * (1 / T - 1 / To)) (To is 298.15K (25C) and Ro is the |
163 | nominal resistance at 25C) | |
61d0b533 JH |
164 | |
165 | Mingling the above two equations and assuming Rs = Ro and B = 3435 yields the | |
cdc39b09 | 166 | following formula for sensors.conf:: |
61d0b533 | 167 | |
cdc39b09 MCC |
168 | compute tempx 1 / (1 / 298.15 - (` (2200 / @ - 1)) / 3435) - 273.15, |
169 | 2200 / (1 + (^ (3435 / 298.15 - 3435 / (273.15 + @)))) | |
61d0b533 JH |
170 | |
171 | ||
172 | Fan Speed Control | |
173 | ----------------- | |
174 | ||
175 | The VT1211 provides 2 programmable PWM outputs to control the speeds of 2 | |
176 | fans. Writing a 2 to any of the two pwm[1-2]_enable sysfs nodes will put the | |
177 | PWM controller in automatic mode. There is only a single controller that | |
178 | controls both PWM outputs but each PWM output can be individually enabled and | |
179 | disabled. | |
180 | ||
181 | Each PWM has 4 associated distinct output duty-cycles: full, high, low and | |
182 | off. Full and off are internally hard-wired to 255 (100%) and 0 (0%), | |
183 | respectively. High and low can be programmed via | |
184 | pwm[1-2]_auto_point[2-3]_pwm. Each PWM output can be associated with a | |
185 | different thermal input but - and here's the weird part - only one set of | |
186 | thermal thresholds exist that controls both PWMs output duty-cycles. The | |
187 | thermal thresholds are accessible via pwm[1-2]_auto_point[1-4]_temp. Note | |
188 | that even though there are 2 sets of 4 auto points each, they map to the same | |
189 | registers in the VT1211 and programming one set is sufficient (actually only | |
190 | the first set pwm1_auto_point[1-4]_temp is writable, the second set is | |
191 | read-only). | |
192 | ||
cdc39b09 | 193 | ========================== ========================================= |
61d0b533 | 194 | PWM Auto Point PWM Output Duty-Cycle |
cdc39b09 | 195 | ========================== ========================================= |
61d0b533 JH |
196 | pwm[1-2]_auto_point4_pwm full speed duty-cycle (hard-wired to 255) |
197 | pwm[1-2]_auto_point3_pwm high speed duty-cycle | |
198 | pwm[1-2]_auto_point2_pwm low speed duty-cycle | |
199 | pwm[1-2]_auto_point1_pwm off duty-cycle (hard-wired to 0) | |
cdc39b09 | 200 | ========================== ========================================= |
61d0b533 | 201 | |
cdc39b09 | 202 | ========================== ================= |
61d0b533 | 203 | Temp Auto Point Thermal Threshold |
cdc39b09 | 204 | ========================== ================= |
61d0b533 JH |
205 | pwm[1-2]_auto_point4_temp full speed temp |
206 | pwm[1-2]_auto_point3_temp high speed temp | |
207 | pwm[1-2]_auto_point2_temp low speed temp | |
208 | pwm[1-2]_auto_point1_temp off temp | |
cdc39b09 | 209 | ========================== ================= |
61d0b533 JH |
210 | |
211 | Long story short, the controller implements the following algorithm to set the | |
212 | PWM output duty-cycle based on the input temperature: | |
213 | ||
cdc39b09 MCC |
214 | =================== ======================= ======================== |
215 | Thermal Threshold Output Duty-Cycle Output Duty-Cycle | |
216 | (Rising Temp) (Falling Temp) | |
217 | =================== ======================= ======================== | |
218 | - full speed duty-cycle full speed duty-cycle | |
61d0b533 | 219 | full speed temp |
cdc39b09 | 220 | - high speed duty-cycle full speed duty-cycle |
61d0b533 | 221 | high speed temp |
cdc39b09 | 222 | - low speed duty-cycle high speed duty-cycle |
61d0b533 | 223 | low speed temp |
cdc39b09 | 224 | - off duty-cycle low speed duty-cycle |
61d0b533 | 225 | off temp |
cdc39b09 | 226 | =================== ======================= ======================== |