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1 | Kernel driver w83627ehf | ||
2 | ======================= | ||
3 | |||
4 | Supported chips: | ||
5 | * Winbond W83627EHF/EHG (ISA access ONLY) | ||
6 | Prefix: 'w83627ehf' | ||
7 | Addresses scanned: ISA address retrieved from Super I/O registers | ||
8 | Datasheet: http://www.winbond-usa.com/products/winbond_products/pdfs/PCIC/W83627EHF_%20W83627EHGb.pdf | ||
9 | |||
10 | Authors: | ||
11 | Jean Delvare <khali@linux-fr.org> | ||
12 | Yuan Mu <Ymu@Winbond.com.tw> | ||
13 | Rudolf Marek <r.marek@sh.cvut.cz> | ||
14 | |||
15 | Description | ||
16 | ----------- | ||
17 | |||
18 | This driver implements support for the Winbond W83627EHF and W83627EHG | ||
19 | super I/O chips. We will refer to them collectively as Winbond chips. | ||
20 | |||
21 | The chips implement three temperature sensors, five fan rotation | ||
22 | speed sensors, ten analog voltage sensors, alarms with beep warnings (control | ||
23 | unimplemented), and some automatic fan regulation strategies (plus manual | ||
24 | fan control mode). | ||
25 | |||
26 | Temperatures are measured in degrees Celsius and measurement resolution is 1 | ||
27 | degC for temp1 and 0.5 degC for temp2 and temp3. An alarm is triggered when | ||
28 | the temperature gets higher than high limit; it stays on until the temperature | ||
29 | falls below the Hysteresis value. | ||
30 | |||
31 | Fan rotation speeds are reported in RPM (rotations per minute). An alarm is | ||
32 | triggered if the rotation speed has dropped below a programmable limit. Fan | ||
33 | readings can be divided by a programmable divider (1, 2, 4, 8, 16, 32, 64 or | ||
34 | 128) to give the readings more range or accuracy. The driver sets the most | ||
35 | suitable fan divisor itself. Some fans might not be present because they | ||
36 | share pins with other functions. | ||
37 | |||
38 | Voltage sensors (also known as IN sensors) report their values in millivolts. | ||
39 | An alarm is triggered if the voltage has crossed a programmable minimum | ||
40 | or maximum limit. | ||
41 | |||
42 | The driver supports automatic fan control mode known as Thermal Cruise. | ||
43 | In this mode, the chip attempts to keep the measured temperature in a | ||
44 | predefined temperature range. If the temperature goes out of range, fan | ||
45 | is driven slower/faster to reach the predefined range again. | ||
46 | |||
47 | The mode works for fan1-fan4. Mapping of temperatures to pwm outputs is as | ||
48 | follows: | ||
49 | |||
50 | temp1 -> pwm1 | ||
51 | temp2 -> pwm2 | ||
52 | temp3 -> pwm3 | ||
53 | prog -> pwm4 (the programmable setting is not supported by the driver) | ||
54 | |||
55 | /sys files | ||
56 | ---------- | ||
57 | |||
58 | pwm[1-4] - this file stores PWM duty cycle or DC value (fan speed) in range: | ||
59 | 0 (stop) to 255 (full) | ||
60 | |||
61 | pwm[1-4]_enable - this file controls mode of fan/temperature control: | ||
62 | * 1 Manual Mode, write to pwm file any value 0-255 (full speed) | ||
63 | * 2 Thermal Cruise | ||
64 | |||
65 | Thermal Cruise mode | ||
66 | ------------------- | ||
67 | |||
68 | If the temperature is in the range defined by: | ||
69 | |||
70 | pwm[1-4]_target - set target temperature, unit millidegree Celcius | ||
71 | (range 0 - 127000) | ||
72 | pwm[1-4]_tolerance - tolerance, unit millidegree Celcius (range 0 - 15000) | ||
73 | |||
74 | there are no changes to fan speed. Once the temperature leaves the interval, | ||
75 | fan speed increases (temp is higher) or decreases if lower than desired. | ||
76 | There are defined steps and times, but not exported by the driver yet. | ||
77 | |||
78 | pwm[1-4]_min_output - minimum fan speed (range 1 - 255), when the temperature | ||
79 | is below defined range. | ||
80 | pwm[1-4]_stop_time - how many milliseconds [ms] must elapse to switch | ||
81 | corresponding fan off. (when the temperature was below | ||
82 | defined range). | ||
83 | |||
84 | Note: last two functions are influenced by other control bits, not yet exported | ||
85 | by the driver, so a change might not have any effect. | ||