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- 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.
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