4 This driver will be removed from github, effective August 1, 2018.
5 Interested parties are encouraged to clone the driver before that
6 time and to start maintaining it on their own.
12 This driver supercedes the NCT6775F and NCT6776F support in the W83627EHF
13 driver. It supports NCT6106D, NCT6775F, NCT6776F, NCT6779D, NCT6791D,
14 NCT6792D, NCT6793D, and NCT6795D.
16 The driver is also available in the upstream kernel. This version is maintained
17 for backward compatibility with older kernels. I am trying to keep it buildable
18 for older kernels, but may miss a problem once in a while. If you have a problem
19 compiling this driver with any kernel version 2.6.32 or later, please let me
23 =======================
26 * Nuvoton NCT6102D/NCT6104D/NCT6106D
28 Addresses scanned: ISA address retrieved from Super I/O registers
29 Datasheet: Available from Nuvoton upon request
30 * Nuvoton NCT6775F/W83667HG-I
32 Addresses scanned: ISA address retrieved from Super I/O registers
33 Datasheet: Available from Nuvoton upon request
36 Addresses scanned: ISA address retrieved from Super I/O registers
37 Datasheet: Available from Nuvoton upon request
40 Addresses scanned: ISA address retrieved from Super I/O registers
41 Datasheet: Available from Nuvoton upon request
44 Addresses scanned: ISA address retrieved from Super I/O registers
45 Datasheet: Available from Nuvoton upon request
48 Addresses scanned: ISA address retrieved from Super I/O registers
49 Datasheet: Available from Nuvoton upon request
52 Addresses scanned: ISA address retrieved from Super I/O registers
53 Datasheet: Available from Nuvoton upon request
56 Addresses scanned: ISA address retrieved from Super I/O registers
57 Datasheet: Available from Nuvoton upon request
60 Guenter Roeck <linux@roeck-us.net>
61 David Bartley <andareed@gmail.com> (NCT6791D support)
66 This driver implements support for the Nuvoton NCT6106D, NCT6775F, NCT6776F,
67 NCT6779D, NCT6791D, NCT6792D, NCT6793D, and NCT6795D super I/O chips.
68 We will refer to them collectively as Nuvoton chips.
70 The chips implement up to 8 temperature sensors depending on the chip type and
71 configuration. Temperatures used to control fan speed are reported separately.
72 There are 3 to 6 fan rotation speed sensors, 8 to 15 analog voltage sensors,
73 one VID, alarms with beep warnings (control unimplemented), and some automatic
74 fan regulation strategies (plus manual fan control mode).
76 The temperature sensor sources on all chips are configurable. temp4 and higher
77 attributes are only reported if its temperature source differs from the
78 temperature sources of the already reported temperature sensors.
79 The configured source for each of the temperature sensors is provided
82 Temperatures are measured in degrees Celsius and measurement resolution is
83 either 1 degC or 0.5 degC, depending on the temperature source and
84 configuration. An alarm is triggered when the temperature gets higher than
85 the high limit; it stays on until the temperature falls below the hysteresis
86 value. Alarms are only supported for temp1, temp2, and temp3.
88 Fan rotation speeds are reported in RPM (rotations per minute). An alarm is
89 triggered if the rotation speed has dropped below a programmable limit. Fan
90 readings can be divided by a programmable divider (1, 2, 4, 8, 16, 32, 64 or
91 128) to give the readings more range or accuracy. The driver sets the most
92 suitable fan divisor itself. Some fans might not be present because they
93 share pins with other functions.
95 Voltage sensors (also known as IN sensors) report their values in millivolts.
96 An alarm is triggered if the voltage has crossed a programmable minimum
99 The driver supports automatic fan control mode known as Thermal Cruise.
100 In this mode, the chip attempts to keep the measured temperature in a
101 predefined temperature range. If the temperature goes out of range, fan
102 is driven slower/faster to reach the predefined range again.
104 The mode works for fan1-fan6.
109 name - this is a standard hwmon device entry, it contains the name of
110 the device (see the prefix in the list of supported devices at
111 the top of this file)
113 pwm[1-6] - this file stores PWM duty cycle or DC value (fan speed) in range:
114 0 (stop) to 255 (full)
116 pwm[1-6]_enable - this file controls mode of fan/temperature control:
117 * 0 Fan control disabled (fans set to maximum speed)
118 * 1 Manual mode, write to pwm file any value 0-255 (full speed)
119 * 2 "Thermal Cruise" mode
120 * 3 "Fan Speed Cruise" mode
121 * 4 "Smart Fan III" mode (NCT6775F only)
122 * 5 "Smart Fan IV" mode
124 pwm[1-6]_mode - controls if output is PWM or DC level
125 * 0 DC output (0 - 12v)
128 Common fan control attributes
129 -----------------------------
131 pwm[1-6]_temp_sel Temperature source. Value is temperature sensor index.
132 For example, select '1' for temp1_input.
133 pwm[1-6]_weight_temp_sel
134 Secondary temperature source. Value is temperature
135 sensor index. For example, select '1' for temp1_input.
136 pwm[1-6]_weight_enable Set to 1 to enable secondary temperature control.
138 If secondary temperature functionality is enabled, it is controlled with the
139 following attributes.
141 pwm[1-6]_weight_duty_step
143 pwm[1-6]_weight_temp_step
144 Temperature step size. With each step over
145 temp_step_base, the value of weight_duty_step is added
146 to the current pwm value.
147 pwm[1-6]_weight_temp_step_base
148 Temperature at which secondary temperature control kicks
150 pwm[1-6]_weight_temp_step_tol
151 Temperature step tolerance or hysteresis. This is a
155 Thermal Cruise mode (2)
156 -----------------------
158 If the temperature is in the range defined by:
160 pwm[1-6]_target Target temperature, unit millidegree Celsius
162 pwm[1-6]_auto_temp1_hyst
163 Hysteresis, unit millidegree Celsius
164 Hysteresis value is relative to pwm[1-6]_auto_temp1.
166 there are no changes to fan speed. Once the temperature leaves the interval,
167 fan speed increases (temp is higher) or decreases if lower than desired,
168 using the following steps and times.
170 pwm[1-6]_start_output fan pwm start value (range 1 - 255), to start fan
171 when the temperature is above defined range.
172 pwm[1-6]_stop_output lowest fan pwm (range 1 - 255) if temperature is below
174 pwm[1-6]_stop_output_enable
175 Set to 1 to enable pwm[1-6]_stop_output. If disabled
176 (set to 0), the fan will stop if the temperature is
177 below the defined range.
178 pwm[1-6]_step_up_time milliseconds [ms] before fan speed is increased
179 pwm[1-6]_step_down_time milliseconds [ms] before fan speed is decreased
180 pwm[1-6]_stop_time how many milliseconds [ms] must elapse to switch
181 corresponding fan off (when the temperature was below
184 Speed Cruise mode (3)
185 ---------------------
187 This modes tries to keep the fan speed constant.
188 Untested; use at your own risk.
190 Smart Fan IV mode (5)
191 ---------------------
193 The fan is regulated to maintain a target temperature. There are five data
194 points. Subsequent data points should be set to higher temperatures and higher
195 pwm values to achieve higher fan speeds with increasing temperature. The last
196 data point reflects critical temperature mode, in which the fans should run at
199 pwm[1-6]_auto_point[1-6]_pwm
200 pwm value to be set if temperature reaches matching
202 pwm[1-6]_auto_point[1-6]_temp
203 Temperature at which the matching pwm is enabled.
204 pwm[1-6]_step_up_time milliseconds [ms] before fan speed is increased
205 pwm[1-6]_step_down_time milliseconds [ms] before fan speed is decreased
211 On various ASUS boards with NCT6776F, it appears that CPUTIN is not really
212 connected to anything and floats, or that it is connected to some non-standard
213 temperature measurement device. As a result, the temperature reported on CPUTIN
214 will not reflect a usable value. It often reports unreasonably high
215 temperatures, and in some cases the reported temperature declines if the actual
216 temperature increases (similar to the raw PECI temperature value - see PECI
217 specification for details). CPUTIN should therefore be be ignored on ASUS
218 boards. The CPU temperature on ASUS boards is reported from PECI 0.
220 Also, there have been reports that not all fan speeds are reported on at least
221 some ASUS boards. P9X79 WS is one example, where fan speed is only reported
222 for two of the fans on the board.
224 Note that ASUS does not support Linux on desktop boards (this appears to be
225 official ASUS policy) and does not release board specifications, so there is
226 nothing we can do to improve support for such boards unless we get board
227 specifications or a detailed description on how to control the fans on the
233 After a suspend/resume cycle, all fan control settings are restored to the BIOS