4 This driver is experimental and has only been tested on NCT6775F.
6 This driver supercedes the NCT6775F and NCT6776F support in the W83627EHF
10 =======================
13 * Nuvoton NCT6775F/W83667HG-I
15 Addresses scanned: ISA address retrieved from Super I/O registers
16 Datasheet: Available from Nuvoton upon request
19 Addresses scanned: ISA address retrieved from Super I/O registers
20 Datasheet: Available from Nuvoton upon request
23 Addresses scanned: ISA address retrieved from Super I/O registers
24 Datasheet: Available from Nuvoton upon request
27 Guenter Roeck <linux@roeck-us.net>
32 This driver implements support for the Nuvoton NCT6775F, NCT6776F, and NCT6779D
33 super I/O chips. We will refer to them collectively as Nuvoton chips.
35 The chips implement 2 to 4 temperature sensors (9 for NCT6775F and NCT6776F),
36 2 to 5 fan rotation speed sensors, 8 to 15 analog voltage sensors, one VID,
37 alarms with beep warnings (control unimplemented), and some automatic fan
38 regulation strategies (plus manual fan control mode).
40 The temperature sensor sources on all chips are configurable. temp4 and higher
41 attributes are only reported if its temperature source differs from the
42 temperature sources of the already reported temperature sensors.
43 The configured source for each of the temperature sensors is provided
46 Temperatures are measured in degrees Celsius and measurement resolution is 1
47 degC for temp1 and and 0.5 degC for temp2 and temp3. For temp4 and higher,
48 resolution is 1 degC for W83667HG-B and 0.5 degC for NCT6775F and NCT6776F.
49 An alarm is triggered when the temperature gets higher than high limit;
50 it stays on until the temperature falls below the hysteresis value.
51 Alarms are only supported for temp1, temp2, and temp3.
53 Fan rotation speeds are reported in RPM (rotations per minute). An alarm is
54 triggered if the rotation speed has dropped below a programmable limit. Fan
55 readings can be divided by a programmable divider (1, 2, 4, 8, 16, 32, 64 or
56 128) to give the readings more range or accuracy. The driver sets the most
57 suitable fan divisor itself. Some fans might not be present because they
58 share pins with other functions.
60 Voltage sensors (also known as IN sensors) report their values in millivolts.
61 An alarm is triggered if the voltage has crossed a programmable minimum
64 The driver supports automatic fan control mode known as Thermal Cruise.
65 In this mode, the chip attempts to keep the measured temperature in a
66 predefined temperature range. If the temperature goes out of range, fan
67 is driven slower/faster to reach the predefined range again.
69 The mode works for fan1-fan4. Mapping of temperatures to pwm outputs is as
79 name - this is a standard hwmon device entry, it contains the name of
80 the device (see the prefix in the list of supported devices at
83 pwm[1-5] - this file stores PWM duty cycle or DC value (fan speed) in range:
84 0 (stop) to 255 (full)
86 pwm[1-5]_enable - this file controls mode of fan/temperature control:
87 * 1 Manual mode, write to pwm file any value 0-255 (full speed)
88 * 2 "Thermal Cruise" mode
89 * 3 "Fan Speed Cruise" mode
90 * 4 "Smart Fan III" mode
91 * 5 "Smart Fan IV" mode
93 SmartFan III mode is not supported on NCT6776F and NCT6779D.
95 pwm[1-5]_mode - controls if output is PWM or DC level
96 * 0 DC output (0 - 12v)
102 If the temperature is in the range defined by:
104 pwm[1-4]_target - set target temperature, unit millidegree Celsius
106 pwm[1-4]_tolerance - tolerance, unit millidegree Celsius (range 0 - 15000)
108 There are no changes to fan speed. Once the temperature leaves the interval,
109 fan speed increases (temp is higher) or decreases if lower than desired.
110 There are defined steps and times, but not exported by the driver yet.
112 pwm[1-4]_min_output - minimum fan speed (range 1 - 255), when the temperature
113 is below defined range.
114 pwm[1-4]_stop_time - how many milliseconds [ms] must elapse to switch
115 corresponding fan off. (when the temperature was below
118 Note: last two functions are influenced by other control bits, not yet exported
119 by the driver, so a change might not have any effect.
121 Implementation Details
122 ----------------------