Commit | Line | Data |
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7f15b664 RM |
1 | Kernel driver pc87360 |
2 | ===================== | |
3 | ||
4 | Supported chips: | |
5 | * National Semiconductor PC87360, PC87363, PC87364, PC87365 and PC87366 | |
6 | Prefixes: 'pc87360', 'pc87363', 'pc87364', 'pc87365', 'pc87366' | |
7 | Addresses scanned: none, address read from Super I/O config space | |
6aa693b8 | 8 | Datasheets: No longer available |
7f15b664 RM |
9 | |
10 | Authors: Jean Delvare <khali@linux-fr.org> | |
11 | ||
12 | Thanks to Sandeep Mehta, Tonko de Rooy and Daniel Ceregatti for testing. | |
13 | Thanks to Rudolf Marek for helping me investigate conversion issues. | |
14 | ||
15 | ||
16 | Module Parameters | |
17 | ----------------- | |
18 | ||
19 | * init int | |
20 | Chip initialization level: | |
21 | 0: None | |
22 | *1: Forcibly enable internal voltage and temperature channels, except in9 | |
23 | 2: Forcibly enable all voltage and temperature channels, except in9 | |
24 | 3: Forcibly enable all voltage and temperature channels, including in9 | |
25 | ||
26 | Note that this parameter has no effect for the PC87360, PC87363 and PC87364 | |
27 | chips. | |
28 | ||
29 | Also note that for the PC87366, initialization levels 2 and 3 don't enable | |
30 | all temperature channels, because some of them share pins with each other, | |
31 | so they can't be used at the same time. | |
32 | ||
33 | ||
34 | Description | |
35 | ----------- | |
36 | ||
37 | The National Semiconductor PC87360 Super I/O chip contains monitoring and | |
38 | PWM control circuitry for two fans. The PC87363 chip is similar, and the | |
39 | PC87364 chip has monitoring and PWM control for a third fan. | |
40 | ||
41 | The National Semiconductor PC87365 and PC87366 Super I/O chips are complete | |
42 | hardware monitoring chipsets, not only controlling and monitoring three fans, | |
43 | but also monitoring eleven voltage inputs and two (PC87365) or up to four | |
44 | (PC87366) temperatures. | |
45 | ||
46 | Chip #vin #fan #pwm #temp devid | |
47 | ||
48 | PC87360 - 2 2 - 0xE1 | |
49 | PC87363 - 2 2 - 0xE8 | |
50 | PC87364 - 3 3 - 0xE4 | |
51 | PC87365 11 3 3 2 0xE5 | |
52 | PC87366 11 3 3 3-4 0xE9 | |
53 | ||
54 | The driver assumes that no more than one chip is present, and one of the | |
55 | standard Super I/O addresses is used (0x2E/0x2F or 0x4E/0x4F) | |
56 | ||
57 | Fan Monitoring | |
58 | -------------- | |
59 | ||
60 | Fan rotation speeds are reported in RPM (revolutions per minute). An alarm | |
61 | is triggered if the rotation speed has dropped below a programmable limit. | |
62 | A different alarm is triggered if the fan speed is too low to be measured. | |
63 | ||
64 | Fan readings are affected by a programmable clock divider, giving the | |
65 | readings more range or accuracy. Usually, users have to learn how it works, | |
66 | but this driver implements dynamic clock divider selection, so you don't | |
67 | have to care no more. | |
68 | ||
69 | For reference, here are a few values about clock dividers: | |
70 | ||
71 | slowest accuracy highest | |
72 | measurable around 3000 accurate | |
73 | divider speed (RPM) RPM (RPM) speed (RPM) | |
74 | 1 1882 18 6928 | |
75 | 2 941 37 4898 | |
76 | 4 470 74 3464 | |
77 | 8 235 150 2449 | |
78 | ||
79 | For the curious, here is how the values above were computed: | |
80 | * slowest measurable speed: clock/(255*divider) | |
81 | * accuracy around 3000 RPM: 3000^2/clock | |
82 | * highest accurate speed: sqrt(clock*100) | |
83 | The clock speed for the PC87360 family is 480 kHz. I arbitrarily chose 100 | |
84 | RPM as the lowest acceptable accuracy. | |
85 | ||
86 | As mentioned above, you don't have to care about this no more. | |
87 | ||
88 | Note that not all RPM values can be represented, even when the best clock | |
89 | divider is selected. This is not only true for the measured speeds, but | |
90 | also for the programmable low limits, so don't be surprised if you try to | |
91 | set, say, fan1_min to 2900 and it finally reads 2909. | |
92 | ||
93 | ||
94 | Fan Control | |
95 | ----------- | |
96 | ||
97 | PWM (pulse width modulation) values range from 0 to 255, with 0 meaning | |
98 | that the fan is stopped, and 255 meaning that the fan goes at full speed. | |
99 | ||
100 | Be extremely careful when changing PWM values. Low PWM values, even | |
101 | non-zero, can stop the fan, which may cause irreversible damage to your | |
102 | hardware if temperature increases too much. When changing PWM values, go | |
103 | step by step and keep an eye on temperatures. | |
104 | ||
105 | One user reported problems with PWM. Changing PWM values would break fan | |
106 | speed readings. No explanation nor fix could be found. | |
107 | ||
108 | ||
109 | Temperature Monitoring | |
110 | ---------------------- | |
111 | ||
112 | Temperatures are reported in degrees Celsius. Each temperature measured has | |
113 | associated low, high and overtemperature limits, each of which triggers an | |
114 | alarm when crossed. | |
115 | ||
116 | The first two temperature channels are external. The third one (PC87366 | |
117 | only) is internal. | |
118 | ||
119 | The PC87366 has three additional temperature channels, based on | |
120 | thermistors (as opposed to thermal diodes for the first three temperature | |
121 | channels). For technical reasons, these channels are held by the VLM | |
122 | (voltage level monitor) logical device, not the TMS (temperature | |
123 | measurement) one. As a consequence, these temperatures are exported as | |
124 | voltages, and converted into temperatures in user-space. | |
125 | ||
126 | Note that these three additional channels share their pins with the | |
127 | external thermal diode channels, so you (physically) can't use them all at | |
128 | the same time. Although it should be possible to mix the two sensor types, | |
129 | the documents from National Semiconductor suggest that motherboard | |
130 | manufacturers should choose one type and stick to it. So you will more | |
131 | likely have either channels 1 to 3 (thermal diodes) or 3 to 6 (internal | |
132 | thermal diode, and thermistors). | |
133 | ||
134 | ||
135 | Voltage Monitoring | |
136 | ------------------ | |
137 | ||
138 | Voltages are reported relatively to a reference voltage, either internal or | |
139 | external. Some of them (in7:Vsb, in8:Vdd and in10:AVdd) are divided by two | |
140 | internally, you will have to compensate in sensors.conf. Others (in0 to in6) | |
141 | are likely to be divided externally. The meaning of each of these inputs as | |
142 | well as the values of the resistors used for division is left to the | |
143 | motherboard manufacturers, so you will have to document yourself and edit | |
144 | sensors.conf accordingly. National Semiconductor has a document with | |
145 | recommended resistor values for some voltages, but this still leaves much | |
146 | room for per motherboard specificities, unfortunately. Even worse, | |
147 | motherboard manufacturers don't seem to care about National Semiconductor's | |
148 | recommendations. | |
149 | ||
150 | Each voltage measured has associated low and high limits, each of which | |
151 | triggers an alarm when crossed. | |
152 | ||
153 | When available, VID inputs are used to provide the nominal CPU Core voltage. | |
154 | The driver will default to VRM 9.0, but this can be changed from user-space. | |
155 | The chipsets can handle two sets of VID inputs (on dual-CPU systems), but | |
156 | the driver will only export one for now. This may change later if there is | |
157 | a need. | |
158 | ||
159 | ||
160 | General Remarks | |
161 | --------------- | |
162 | ||
163 | If an alarm triggers, it will remain triggered until the hardware register | |
164 | is read at least once. This means that the cause for the alarm may already | |
165 | have disappeared! Note that all hardware registers are read whenever any | |
166 | data is read (unless it is less than 2 seconds since the last update, in | |
167 | which case cached values are returned instead). As a consequence, when | |
168 | a once-only alarm triggers, it may take 2 seconds for it to show, and 2 | |
169 | more seconds for it to disappear. | |
170 | ||
171 | Monitoring of in9 isn't enabled at lower init levels (<3) because that | |
172 | channel measures the battery voltage (Vbat). It is a known fact that | |
173 | repeatedly sampling the battery voltage reduces its lifetime. National | |
174 | Semiconductor smartly designed their chipset so that in9 is sampled only | |
175 | once every 1024 sampling cycles (that is every 34 minutes at the default | |
176 | sampling rate), so the effect is attenuated, but still present. | |
177 | ||
178 | ||
179 | Limitations | |
180 | ----------- | |
181 | ||
182 | The datasheets suggests that some values (fan mins, fan dividers) | |
183 | shouldn't be changed once the monitoring has started, but we ignore that | |
184 | recommendation. We'll reconsider if it actually causes trouble. |