| Note |
| ==== |
| |
| This driver supersedes the NCT6775F and NCT6776F support in the W83627EHF |
| driver. |
| |
| Kernel driver NCT6775 |
| ===================== |
| |
| Supported chips: |
| * Nuvoton NCT5572D/NCT6771F/NCT6772F/NCT6775F/W83677HG-I |
| Prefix: 'nct6775' |
| Addresses scanned: ISA address retrieved from Super I/O registers |
| Datasheet: Available from Nuvoton upon request |
| * Nuvoton NCT5577D/NCT6776D/NCT6776F |
| Prefix: 'nct6776' |
| Addresses scanned: ISA address retrieved from Super I/O registers |
| Datasheet: Available from Nuvoton upon request |
| * Nuvoton NCT5532D/NCT6779D |
| Prefix: 'nct6779' |
| Addresses scanned: ISA address retrieved from Super I/O registers |
| Datasheet: Available from Nuvoton upon request |
| |
| Authors: |
| Guenter Roeck <linux@roeck-us.net> |
| |
| Description |
| ----------- |
| |
| This driver implements support for the Nuvoton NCT6775F, NCT6776F, and NCT6779D |
| and compatible super I/O chips. |
| |
| The chips support up to 25 temperature monitoring sources. Up to 6 of those are |
| direct temperature sensor inputs, the others are special sources such as PECI, |
| PCH, and SMBUS. Depending on the chip type, 2 to 6 of the temperature sources |
| can be monitored and compared against minimum, maximum, and critical |
| temperatures. The driver reports up to 10 of the temperatures to the user. |
| There are 4 to 5 fan rotation speed sensors, 8 to 15 analog voltage sensors, |
| one VID, alarms with beep warnings (control unimplemented), and some automatic |
| fan regulation strategies (plus manual fan control mode). |
| |
| The temperature sensor sources on all chips are configurable. The configured |
| source for each of the temperature sensors is provided in tempX_label. |
| |
| Temperatures are measured in degrees Celsius and measurement resolution is |
| either 1 degC or 0.5 degC, depending on the temperature source and |
| configuration. An alarm is triggered when the temperature gets higher than |
| the high limit; it stays on until the temperature falls below the hysteresis |
| value. Alarms are only supported for temp1 to temp6, depending on the chip type. |
| |
| Fan rotation speeds are reported in RPM (rotations per minute). An alarm is |
| triggered if the rotation speed has dropped below a programmable limit. On |
| NCT6775F, 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 other chips |
| do not have a fan speed divider. The driver sets the most suitable fan divisor |
| itself; specifically, it increases the divider value each time a fan speed |
| reading returns an invalid value, and it reduces it if the fan speed reading |
| is lower than optimal. 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-fan5. |
| |
| sysfs attributes |
| ---------------- |
| |
| pwm[1-5] - this file stores PWM duty cycle or DC value (fan speed) in range: |
| 0 (lowest speed) to 255 (full) |
| |
| pwm[1-5]_enable - this file controls mode of fan/temperature control: |
| * 0 Fan control disabled (fans set to maximum speed) |
| * 1 Manual mode, write to pwm[0-5] any value 0-255 |
| * 2 "Thermal Cruise" mode |
| * 3 "Fan Speed Cruise" mode |
| * 4 "Smart Fan III" mode (NCT6775F only) |
| * 5 "Smart Fan IV" mode |
| |
| pwm[1-5]_mode - controls if output is PWM or DC level |
| * 0 DC output |
| * 1 PWM output |
| |
| Common fan control attributes |
| ----------------------------- |
| |
| pwm[1-5]_temp_sel Temperature source. Value is temperature sensor index. |
| For example, select '1' for temp1_input. |
| pwm[1-5]_weight_temp_sel |
| Secondary temperature source. Value is temperature |
| sensor index. For example, select '1' for temp1_input. |
| Set to 0 to disable secondary temperature control. |
| |
| If secondary temperature functionality is enabled, it is controlled with the |
| following attributes. |
| |
| pwm[1-5]_weight_duty_step |
| Duty step size. |
| pwm[1-5]_weight_temp_step |
| Temperature step size. With each step over |
| temp_step_base, the value of weight_duty_step is added |
| to the current pwm value. |
| pwm[1-5]_weight_temp_step_base |
| Temperature at which secondary temperature control kicks |
| in. |
| pwm[1-5]_weight_temp_step_tol |
| Temperature step tolerance. |
| |
| Thermal Cruise mode (2) |
| ----------------------- |
| |
| If the temperature is in the range defined by: |
| |
| pwm[1-5]_target_temp Target temperature, unit millidegree Celsius |
| (range 0 - 127000) |
| pwm[1-5]_temp_tolerance |
| Target temperature tolerance, unit millidegree Celsius |
| |
| there are no changes to fan speed. Once the temperature leaves the interval, fan |
| speed increases (if temperature is higher that desired) or decreases (if |
| temperature is lower than desired), using the following limits and time |
| intervals. |
| |
| pwm[1-5]_start fan pwm start value (range 1 - 255), to start fan |
| when the temperature is above defined range. |
| pwm[1-5]_floor lowest fan pwm (range 0 - 255) if temperature is below |
| the defined range. If set to 0, the fan is expected to |
| stop if the temperature is below the defined range. |
| pwm[1-5]_step_up_time milliseconds before fan speed is increased |
| pwm[1-5]_step_down_time milliseconds before fan speed is decreased |
| pwm[1-5]_stop_time how many milliseconds must elapse to switch |
| corresponding fan off (when the temperature was below |
| defined range). |
| |
| Speed Cruise mode (3) |
| --------------------- |
| |
| This modes tries to keep the fan speed constant. |
| |
| fan[1-5]_target Target fan speed |
| fan[1-5]_tolerance |
| Target speed tolerance |
| |
| |
| Untested; use at your own risk. |
| |
| Smart Fan IV mode (5) |
| --------------------- |
| |
| This mode offers multiple slopes to control the fan speed. The slopes can be |
| controlled by setting the pwm and temperature attributes. When the temperature |
| rises, the chip will calculate the DC/PWM output based on the current slope. |
| There are up to seven data points depending on the chip type. Subsequent data |
| points should be set to higher temperatures and higher pwm values to achieve |
| higher fan speeds with increasing temperature. The last data point reflects |
| critical temperature mode, in which the fans should run at full speed. |
| |
| pwm[1-5]_auto_point[1-7]_pwm |
| pwm value to be set if temperature reaches matching |
| temperature range. |
| pwm[1-5]_auto_point[1-7]_temp |
| Temperature over which the matching pwm is enabled. |
| pwm[1-5]_temp_tolerance |
| Temperature tolerance, unit millidegree Celsius |
| pwm[1-5]_crit_temp_tolerance |
| Temperature tolerance for critical temperature, |
| unit millidegree Celsius |
| |
| pwm[1-5]_step_up_time milliseconds before fan speed is increased |
| pwm[1-5]_step_down_time milliseconds before fan speed is decreased |
| |
| Usage Notes |
| ----------- |
| |
| On various ASUS boards with NCT6776F, it appears that CPUTIN is not really |
| connected to anything and floats, or that it is connected to some non-standard |
| temperature measurement device. As a result, the temperature reported on CPUTIN |
| will not reflect a usable value. It often reports unreasonably high |
| temperatures, and in some cases the reported temperature declines if the actual |
| temperature increases (similar to the raw PECI temperature value - see PECI |
| specification for details). CPUTIN should therefore be be ignored on ASUS |
| boards. The CPU temperature on ASUS boards is reported from PECI 0. |
