1 Kernel driver vt1211
2 ====================
3
4 Supported chips:
5
6 * VIA VT1211
7
8 Prefix: 'vt1211'
9
10 Addresses scanned: none, address read from
11
12 Datasheet: Provided by VIA upon request an
13
14 Authors: Juerg Haefliger <juergh@gmail.com>
15
16 This driver is based on the driver for kernel
17 its port to kernel 2.6 by Lars Ekman.
18
19 Thanks to Joseph Chan and Fiona Gatt from VIA
20 technical support.
21
22
23 Module Parameters
24 -----------------
25
26
27 * uch_config: int
28 Override the BIOS defa
29 configuration for chan
30 Legal values are in th
31 UCH1, bit 1 maps to UC
32 enables the thermal in
33 setting a bit to 0 ena
34
35 * int_mode: int
36 Override the BIOS defa
37 The only possible valu
38 mode 0. In this mode,
39 when the status regist
40 long as the temperatur
41 limit.
42
43 Be aware that overriding BIOS defaults might c
44
45
46 Description
47 -----------
48
49 The VIA VT1211 Super-I/O chip includes complet
50 capabilities. It monitors 2 dedicated temperat
51 temp2), 1 dedicated voltage (in5) and 2 fans.
52 implements 5 universal input channels (UCH1-5)
53 programmed to either monitor a voltage or a te
54
55 This chip also provides manual and automatic c
56 to the datasheet). The driver only supports au
57 mode doesn't seem to work as advertised in the
58 get manual mode to work at all! Be aware that
59 tested very well (due to the fact that my EPIA
60 connected to the PWM outputs of the VT1211 :-(
61
62 The following table shows the relationship bet
63 sysfs nodes.
64
65 =============== ============== =========== ===
66 Sensor Voltage Mode Temp Mode Def
67 =============== ============== =========== ===
68 Reading 1 temp1 Int
69 Reading 3 temp2 Int
70 UCH1/Reading2 in0 temp3 NTC
71 UCH2 in1 temp4 +2.
72 UCH3 in2 temp5 Vcc
73 UCH4 in3 temp6 +5V
74 UCH5 in4 temp7 +12
75 +3.3V in5 Int
76 =============== ============== =========== ===
77
78
79 Voltage Monitoring
80 ------------------
81
82 Voltages are sampled by an 8-bit ADC with a LS
83 range is thus from 0 to 2.60V. Voltage values
84 external scaling resistors. This external scal
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
90 follows. And this is of course totally depende
91 implementation :-) You will have to find docum
92 motherboard and edit sensors.conf accordingly.
93
94 ============= ====== ====== ========= ========
95 Expected
96 Voltage R1 R2 Divider Raw Valu
97 ============= ====== ====== ========= ========
98 +2.5V 2K 10K 1.2 2083 mV
99 VccP --- --- 1.0 1400 mV
100 +5V 14K 10K 2.4 2083 mV
101 +12V 47K 10K 5.7 2105 mV
102 +3.3V (int) 2K 3.4K 1.588 3300 mV
103 +3.3V (ext) 6.8K 10K 1.68 1964 mV
104 ============= ====== ====== ========= ========
105
106 .. [1] Depending on the CPU (1.4V is for a VIA
107
108 .. [2] R1 and R2 for 3.3V (int) are internal t
109 performs the scaling and returns the pr
110
111 Each measured voltage has an associated low an
112 alarm when crossed.
113
114
115 Temperature Monitoring
116 ----------------------
117
118 Temperatures are reported in millidegree Celsi
119 has a high limit which triggers an alarm if cr
120 hysteresis value with each temperature below w
121 before the alarm is cleared (this is only true
122 interrupt mode can be forced to 0 in case the
123 automatically. See the 'Module Parameters' sec
124
125 All temperature channels except temp2 are exte
126 internal thermal diode and the driver does all
127 returns the temperature in millidegree Celsius
128 temp1 and temp3-temp7, scaling depends on the
129 to be performed in userspace via sensors.conf.
130
131 Temp1 is an Intel-type thermal diode which req
132 convert between sysfs readings and real temper
133
134 compute temp1 (@-Offset)/Gain, (@*Gain)+Offset
135
136 According to the VIA VT1211 BIOS porting guide
137 values should be used:
138
139 =============== ======== ===========
140 Diode Type Offset Gain
141 =============== ======== ===========
142 Intel CPU 88.638 0.9528
143 65.000 0.9686 [3]_
144 VIA C3 Ezra 83.869 0.9528
145 VIA C3 Ezra-T 73.869 0.9528
146 =============== ======== ===========
147
148 .. [3] This is the formula from the lm_sensors
149 know where it comes from or how it was
150 completeness.
151
152 Temp3-temp7 support NTC thermistors. For these
153 the voltages as seen at the individual pins of
154 pin (Vpin) is formed by a voltage divider made
155 scaling resistor (Rs)::
156
157 Vpin = 2200 * Rth / (Rs + Rth) (2200 is th
158
159 The equation for the thermistor is as follows
160 more about it)::
161
162 Rth = Ro * exp(B * (1 / T - 1 / To)) (To i
163 nomi
164
165 Mingling the above two equations and assuming
166 following formula for sensors.conf::
167
168 compute tempx 1 / (1 / 298.15 - (` (2200 / @
169 2200 / (1 + (^ (3435 / 298.15
170
171
172 Fan Speed Control
173 -----------------
174
175 The VT1211 provides 2 programmable PWM outputs
176 fans. Writing a 2 to any of the two pwm[1-2]_e
177 PWM controller in automatic mode. There is onl
178 controls both PWM outputs but each PWM output
179 disabled.
180
181 Each PWM has 4 associated distinct output duty
182 off. Full and off are internally hard-wired to
183 respectively. High and low can be programmed v
184 pwm[1-2]_auto_point[2-3]_pwm. Each PWM output
185 different thermal input but - and here's the w
186 thermal thresholds exist that controls both PW
187 thermal thresholds are accessible via pwm[1-2]
188 that even though there are 2 sets of 4 auto po
189 registers in the VT1211 and programming one se
190 the first set pwm1_auto_point[1-4]_temp is wri
191 read-only).
192
193 ========================== ===================
194 PWM Auto Point PWM Output Duty-Cyc
195 ========================== ===================
196 pwm[1-2]_auto_point4_pwm full speed duty-cyc
197 pwm[1-2]_auto_point3_pwm high speed duty-cyc
198 pwm[1-2]_auto_point2_pwm low speed duty-cycl
199 pwm[1-2]_auto_point1_pwm off duty-cycle (har
200 ========================== ===================
201
202 ========================== =================
203 Temp Auto Point Thermal Threshold
204 ========================== =================
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
209 ========================== =================
210
211 Long story short, the controller implements th
212 PWM output duty-cycle based on the input tempe
213
214 =================== ======================= ==
215 Thermal Threshold Output Duty-Cycle Ou
216 (Rising Temp) (F
217 =================== ======================= ==
218 - full speed duty-cycle fu
219 full speed temp
220 - high speed duty-cycle fu
221 high speed temp
222 - low speed duty-cycle hi
223 low speed temp
224 - off duty-cycle lo
225 off temp
226 =================== ======================= ==
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