| Kernel driver w83627ehf |
| ======================= |
| |
| Supported chips: |
| * Winbond W83627EHF/EHG (ISA access ONLY) |
| Prefix: 'w83627ehf' |
| Addresses scanned: ISA address retrieved from Super I/O registers |
| Datasheet: http://www.winbond-usa.com/products/winbond_products/pdfs/PCIC/W83627EHF_%20W83627EHGb.pdf |
| |
| Authors: |
| Jean Delvare <khali@linux-fr.org> |
| Yuan Mu (Winbond) |
| Rudolf Marek <r.marek@sh.cvut.cz> |
| |
| Description |
| ----------- |
| |
| This driver implements support for the Winbond W83627EHF and W83627EHG |
| super I/O chips. We will refer to them collectively as Winbond chips. |
| |
| The chips implement three temperature sensors, five fan rotation |
| speed sensors, ten analog voltage sensors, alarms with beep warnings (control |
| unimplemented), and some automatic fan regulation strategies (plus manual |
| fan control mode). |
| |
| Temperatures are measured in degrees Celsius and measurement resolution is 1 |
| degC for temp1 and 0.5 degC for temp2 and temp3. An alarm is triggered when |
| the temperature gets higher than high limit; it stays on until the temperature |
| falls below the hysteresis value. |
| |
| Fan rotation speeds are reported in RPM (rotations per minute). An alarm is |
| triggered if the rotation speed has dropped below a programmable limit. Fan |
| readings can be divided by a programmable divider (1, 2, 4, 8, 16, 32, 64 or |
| 128) to give the readings more range or accuracy. The driver sets the most |
| suitable fan divisor itself. Some fans might not be present because they |
| share pins with other functions. |
| |
| Voltage sensors (also known as IN sensors) report their values in millivolts. |
| An alarm is triggered if the voltage has crossed a programmable minimum |
| or maximum limit. |
| |
| The driver supports automatic fan control mode known as Thermal Cruise. |
| In this mode, the chip attempts to keep the measured temperature in a |
| predefined temperature range. If the temperature goes out of range, fan |
| is driven slower/faster to reach the predefined range again. |
| |
| The mode works for fan1-fan4. Mapping of temperatures to pwm outputs is as |
| follows: |
| |
| temp1 -> pwm1 |
| temp2 -> pwm2 |
| temp3 -> pwm3 |
| prog -> pwm4 (the programmable setting is not supported by the driver) |
| |
| /sys files |
| ---------- |
| |
| pwm[1-4] - this file stores PWM duty cycle or DC value (fan speed) in range: |
| 0 (stop) to 255 (full) |
| |
| pwm[1-4]_enable - this file controls mode of fan/temperature control: |
| * 1 Manual Mode, write to pwm file any value 0-255 (full speed) |
| * 2 Thermal Cruise |
| |
| Thermal Cruise mode |
| ------------------- |
| |
| If the temperature is in the range defined by: |
| |
| pwm[1-4]_target - set target temperature, unit millidegree Celsius |
| (range 0 - 127000) |
| pwm[1-4]_tolerance - tolerance, unit millidegree Celsius (range 0 - 15000) |
| |
| there are no changes to fan speed. Once the temperature leaves the interval, |
| fan speed increases (temp is higher) or decreases if lower than desired. |
| There are defined steps and times, but not exported by the driver yet. |
| |
| pwm[1-4]_min_output - minimum fan speed (range 1 - 255), when the temperature |
| is below defined range. |
| pwm[1-4]_stop_time - how many milliseconds [ms] must elapse to switch |
| corresponding fan off. (when the temperature was below |
| defined range). |
| |
| Note: last two functions are influenced by other control bits, not yet exported |
| by the driver, so a change might not have any effect. |