]>
Commit | Line | Data |
---|---|---|
563daaf4 RM |
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. |