projects / linux-2.6-block.git / blame
| 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. |