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Add description of pwm[1-4]_start_output, pwm[1-4]_step_output, pwm[1-4]_stop_output, and pwm[1-4]_max_output attributes to driver documentation. Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com> Acked-by: Jean Delvare <khali@linux-fr.org>
190 lines
8 KiB
Text
190 lines
8 KiB
Text
Kernel driver w83627ehf
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=======================
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Supported chips:
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* Winbond W83627EHF/EHG (ISA access ONLY)
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Prefix: 'w83627ehf'
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Addresses scanned: ISA address retrieved from Super I/O registers
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Datasheet: not available
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* Winbond W83627DHG
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Prefix: 'w83627dhg'
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Addresses scanned: ISA address retrieved from Super I/O registers
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Datasheet: not available
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* Winbond W83627DHG-P
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Prefix: 'w83627dhg'
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Addresses scanned: ISA address retrieved from Super I/O registers
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Datasheet: not available
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* Winbond W83627UHG
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Prefix: 'w83627uhg'
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Addresses scanned: ISA address retrieved from Super I/O registers
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Datasheet: available from www.nuvoton.com
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* Winbond W83667HG
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Prefix: 'w83667hg'
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Addresses scanned: ISA address retrieved from Super I/O registers
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Datasheet: not available
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* Winbond W83667HG-B
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Prefix: 'w83667hg'
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Addresses scanned: ISA address retrieved from Super I/O registers
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Datasheet: Available from Nuvoton upon request
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* Nuvoton NCT6775F/W83667HG-I
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Prefix: 'nct6775'
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Addresses scanned: ISA address retrieved from Super I/O registers
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Datasheet: Available from Nuvoton upon request
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* Nuvoton NCT6776F
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Prefix: 'nct6776'
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Addresses scanned: ISA address retrieved from Super I/O registers
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Datasheet: Available from Nuvoton upon request
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Authors:
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Jean Delvare <khali@linux-fr.org>
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Yuan Mu (Winbond)
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Rudolf Marek <r.marek@assembler.cz>
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David Hubbard <david.c.hubbard@gmail.com>
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Gong Jun <JGong@nuvoton.com>
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Description
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-----------
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This driver implements support for the Winbond W83627EHF, W83627EHG,
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W83627DHG, W83627DHG-P, W83627UHG, W83667HG, W83667HG-B, W83667HG-I
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(NCT6775F), and NCT6776F super I/O chips. We will refer to them collectively
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as Winbond chips.
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The chips implement 3 to 4 temperature sensors (9 for NCT6775F and NCT6776F),
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2 to 5 fan rotation speed sensors, 8 to 10 analog voltage sensors, one VID
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(except for 627UHG), alarms with beep warnings (control unimplemented),
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and some automatic fan regulation strategies (plus manual fan control mode).
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The temperature sensor sources on W82677HG-B, NCT6775F, and NCT6776F are
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configurable. temp4 and higher attributes are only reported if its temperature
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source differs from the temperature sources of the already reported temperature
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sensors. The configured source for each of the temperature sensors is provided
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in tempX_label.
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Temperatures are measured in degrees Celsius and measurement resolution is 1
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degC for temp1 and and 0.5 degC for temp2 and temp3. For temp4 and higher,
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resolution is 1 degC for W83667HG-B and 0.0 degC for NCT6775F and NCT6776F.
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An alarm is triggered when the temperature gets higher than high limit;
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it stays on until the temperature falls below the hysteresis value.
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Alarms are only supported for temp1, temp2, and temp3.
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Fan rotation speeds are reported in RPM (rotations per minute). An alarm is
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triggered if the rotation speed has dropped below a programmable limit. Fan
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readings can be divided by a programmable divider (1, 2, 4, 8, 16, 32, 64 or
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128) to give the readings more range or accuracy. The driver sets the most
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suitable fan divisor itself. Some fans might not be present because they
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share pins with other functions.
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Voltage sensors (also known as IN sensors) report their values in millivolts.
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An alarm is triggered if the voltage has crossed a programmable minimum
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or maximum limit.
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The driver supports automatic fan control mode known as Thermal Cruise.
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In this mode, the chip attempts to keep the measured temperature in a
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predefined temperature range. If the temperature goes out of range, fan
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is driven slower/faster to reach the predefined range again.
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The mode works for fan1-fan4. Mapping of temperatures to pwm outputs is as
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follows:
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temp1 -> pwm1
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temp2 -> pwm2
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temp3 -> pwm3 (not on 627UHG)
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prog -> pwm4 (not on 667HG and 667HG-B; the programmable setting is not
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supported by the driver)
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/sys files
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----------
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name - this is a standard hwmon device entry, it contains the name of
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the device (see the prefix in the list of supported devices at
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the top of this file)
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pwm[1-4] - this file stores PWM duty cycle or DC value (fan speed) in range:
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0 (stop) to 255 (full)
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pwm[1-4]_enable - this file controls mode of fan/temperature control:
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* 1 Manual mode, write to pwm file any value 0-255 (full speed)
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* 2 "Thermal Cruise" mode
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* 3 "Fan Speed Cruise" mode
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* 4 "Smart Fan III" mode
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* 5 "Smart Fan IV" mode
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SmartFan III mode is not supported on NCT6776F.
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SmartFan IV mode is configurable only if it was configured at system
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startup, and is only supported for W83677HG-B, NCT6775F, and NCT6776F.
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SmartFan IV operational parameters can not be configured at this time,
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and the various pwm attributes are not used in SmartFan IV mode.
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The attributes can be written to, which is useful if you plan to
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configure the system for a different pwm mode. However, the information
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returned when reading pwm attributes is unrelated to SmartFan IV
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operation.
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pwm[1-4]_mode - controls if output is PWM or DC level
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* 0 DC output (0 - 12v)
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* 1 PWM output
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Thermal Cruise mode
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-------------------
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If the temperature is in the range defined by:
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pwm[1-4]_target - set target temperature, unit millidegree Celsius
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(range 0 - 127000)
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pwm[1-4]_tolerance - tolerance, unit millidegree Celsius (range 0 - 15000)
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there are no changes to fan speed. Once the temperature leaves the interval,
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fan speed increases (temp is higher) or decreases if lower than desired.
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There are defined steps and times, but not exported by the driver yet.
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pwm[1-4]_min_output - minimum fan speed (range 1 - 255), when the temperature
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is below defined range.
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pwm[1-4]_stop_time - how many milliseconds [ms] must elapse to switch
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corresponding fan off. (when the temperature was below
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defined range).
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pwm[1-4]_start_output-minimum fan speed (range 1 - 255) when spinning up
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pwm[1-4]_step_output- rate of fan speed change (1 - 255)
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pwm[1-4]_stop_output- minimum fan speed (range 1 - 255) when spinning down
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pwm[1-4]_max_output - maximum fan speed (range 1 - 255), when the temperature
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is above defined range.
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Note: last six functions are influenced by other control bits, not yet exported
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by the driver, so a change might not have any effect.
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Implementation Details
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----------------------
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Future driver development should bear in mind that the following registers have
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different functions on the 627EHF and the 627DHG. Some registers also have
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different power-on default values, but BIOS should already be loading
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appropriate defaults. Note that bank selection must be performed as is currently
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done in the driver for all register addresses.
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0x49: only on DHG, selects temperature source for AUX fan, CPU fan0
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0x4a: not completely documented for the EHF and the DHG documentation assigns
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different behavior to bits 7 and 6, including extending the temperature
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input selection to SmartFan I, not just SmartFan III. Testing on the EHF
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will reveal whether they are compatible or not.
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0x58: Chip ID: 0xa1=EHF 0xc1=DHG
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0x5e: only on DHG, has bits to enable "current mode" temperature detection and
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critical temperature protection
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0x45b: only on EHF, bit 3, vin4 alarm (EHF supports 10 inputs, only 9 on DHG)
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0x552: only on EHF, vin4
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0x558: only on EHF, vin4 high limit
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0x559: only on EHF, vin4 low limit
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0x6b: only on DHG, SYS fan critical temperature
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0x6c: only on DHG, CPU fan0 critical temperature
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0x6d: only on DHG, AUX fan critical temperature
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0x6e: only on DHG, CPU fan1 critical temperature
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0x50-0x55 and 0x650-0x657 are marked "Test Register" for the EHF, but "Reserved
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Register" for the DHG
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The DHG also supports PECI, where the DHG queries Intel CPU temperatures, and
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the ICH8 southbridge gets that data via PECI from the DHG, so that the
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southbridge drives the fans. And the DHG supports SST, a one-wire serial bus.
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The DHG-P has an additional automatic fan speed control mode named Smart Fan
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(TM) III+. This mode is not yet supported by the driver.
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