| Note |
| ==== |
| |
| This driver supersedes the NCT6775F and NCT6776F support in the W83627EHF |
| driver. |
| |
| Kernel driver NCT6775 |
| ===================== |
| |
| Supported chips: |
| * Nuvoton NCT6775F/W83667HG-I |
| Prefix: 'nct6775' |
| Addresses scanned: ISA address retrieved from Super I/O registers |
| Datasheet: Available from Nuvoton upon request |
| * Nuvoton NCT6776F |
| Prefix: 'nct6776' |
| Addresses scanned: ISA address retrieved from Super I/O registers |
| Datasheet: Available from Nuvoton upon request |
| * Nuvoton 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 |
| 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 doubles the divider value each time a fan speed reading |
| returns an invalid value. 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. |
| |
| 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. |
