diff options
Diffstat (limited to 'Documentation/hwmon/nct6775')
| -rw-r--r-- | Documentation/hwmon/nct6775 | 81 |
1 files changed, 81 insertions, 0 deletions
diff --git a/Documentation/hwmon/nct6775 b/Documentation/hwmon/nct6775 new file mode 100644 index 000000000000..ccfd5cc21006 --- /dev/null +++ b/Documentation/hwmon/nct6775 @@ -0,0 +1,81 @@ +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. |