diff options
| -rw-r--r-- | Documentation/hwmon/w83627ehf | 85 |
1 files changed, 85 insertions, 0 deletions
diff --git a/Documentation/hwmon/w83627ehf b/Documentation/hwmon/w83627ehf new file mode 100644 index 000000000000..1474e78d5d32 --- /dev/null +++ b/Documentation/hwmon/w83627ehf @@ -0,0 +1,85 @@ +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 <Ymu@Winbond.com.tw> + 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 Celcius + (range 0 - 127000) +pwm[1-4]_tolerance - tolerance, unit millidegree Celcius (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. |