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diff --git a/Documentation/hwmon/w83627ehf b/Documentation/hwmon/w83627ehf new file mode 100644 index 0000000..d6e1ae3 --- /dev/null +++ b/Documentation/hwmon/w83627ehf @@ -0,0 +1,126 @@ +Kernel driver w83627ehf +======================= + +Supported chips: + * Winbond W83627EHF/EHG/DHG (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 + DHG datasheet confidential. + +Authors: + Jean Delvare <khali@linux-fr.org> + Yuan Mu (Winbond) + Rudolf Marek <r.marek@assembler.cz> + David Hubbard <david.c.hubbard@gmail.com> + +Description +----------- + +This driver implements support for the Winbond W83627EHF, W83627EHG, and +W83627DHG 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 (only nine for the 627DHG), one +VID (6 pins for the 627EHF/EHG, 8 pins for the 627DHG), 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 +---------- + +name - this is a standard hwmon device entry. For the W83627EHF and W83627EHG, + it is set to "w83627ehf" and for the W83627DHG it is set to "w83627dhg" + +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. + +Implementation Details +---------------------- + +Future driver development should bear in mind that the following registers have +different functions on the 627EHF and the 627DHG. Some registers also have +different power-on default values, but BIOS should already be loading +appropriate defaults. Note that bank selection must be performed as is currently +done in the driver for all register addresses. + +0x49: only on DHG, selects temperature source for AUX fan, CPU fan0 +0x4a: not completely documented for the EHF and the DHG documentation assigns + different behavior to bits 7 and 6, including extending the temperature + input selection to SmartFan I, not just SmartFan III. Testing on the EHF + will reveal whether they are compatible or not. + +0x58: Chip ID: 0xa1=EHF 0xc1=DHG +0x5e: only on DHG, has bits to enable "current mode" temperature detection and + critical temperature protection +0x45b: only on EHF, bit 3, vin4 alarm (EHF supports 10 inputs, only 9 on DHG) +0x552: only on EHF, vin4 +0x558: only on EHF, vin4 high limit +0x559: only on EHF, vin4 low limit +0x6b: only on DHG, SYS fan critical temperature +0x6c: only on DHG, CPU fan0 critical temperature +0x6d: only on DHG, AUX fan critical temperature +0x6e: only on DHG, CPU fan1 critical temperature + +0x50-0x55 and 0x650-0x657 are marked "Test Register" for the EHF, but "Reserved + Register" for the DHG + +The DHG also supports PECI, where the DHG queries Intel CPU temperatures, and +the ICH8 southbridge gets that data via PECI from the DHG, so that the +southbridge drives the fans. And the DHG supports SST, a one-wire serial bus. |
