4 This driver supercedes the NCT6775F and NCT6776F support in the W83627EHF
5 driver. It supports NCT6106D, NCT6775F, NCT6776F, NCT6779D, NCT6791D,
6 NCT6792D, NCT6793D, and NCT6795D.
8 The driver is also available in the upstream kernel. This version is maintained
9 for backward compatibility with older kernels. I am trying to keep it buildable
10 for older kernels, but may miss a problem once in a while. If you have a problem
11 compiling this driver with any kernel version 2.6.32 or later, please let me
15 =======================
18 * Nuvoton NCT6102D/NCT6104D/NCT6106D
20 Addresses scanned: ISA address retrieved from Super I/O registers
21 Datasheet: Available from Nuvoton upon request
22 * Nuvoton NCT6775F/W83667HG-I
24 Addresses scanned: ISA address retrieved from Super I/O registers
25 Datasheet: Available from Nuvoton upon request
28 Addresses scanned: ISA address retrieved from Super I/O registers
29 Datasheet: Available from Nuvoton upon request
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 Guenter Roeck <linux@roeck-us.net>
53 David Bartley <andareed@gmail.com> (NCT6791D support)
58 This driver implements support for the Nuvoton NCT6106D, NCT6775F, NCT6776F,
59 NCT6779D, NCT6791D, NCT6792D, NCT6793D, and NCT6795D super I/O chips.
60 We will refer to them collectively as Nuvoton chips.
62 The chips implement up to 8 temperature sensors depending on the chip type and
63 configuration. Temperatures used to control fan speed are reported separately.
64 There are 3 to 6 fan rotation speed sensors, 8 to 15 analog voltage sensors,
65 one VID, alarms with beep warnings (control unimplemented), and some automatic
66 fan regulation strategies (plus manual fan control mode).
68 The temperature sensor sources on all chips are configurable. temp4 and higher
69 attributes are only reported if its temperature source differs from the
70 temperature sources of the already reported temperature sensors.
71 The configured source for each of the temperature sensors is provided
74 Temperatures are measured in degrees Celsius and measurement resolution is
75 either 1 degC or 0.5 degC, depending on the temperature source and
76 configuration. An alarm is triggered when the temperature gets higher than
77 the high limit; it stays on until the temperature falls below the hysteresis
78 value. Alarms are only supported for temp1, temp2, and temp3.
80 Fan rotation speeds are reported in RPM (rotations per minute). An alarm is
81 triggered if the rotation speed has dropped below a programmable limit. Fan
82 readings can be divided by a programmable divider (1, 2, 4, 8, 16, 32, 64 or
83 128) to give the readings more range or accuracy. The driver sets the most
84 suitable fan divisor itself. Some fans might not be present because they
85 share pins with other functions.
87 Voltage sensors (also known as IN sensors) report their values in millivolts.
88 An alarm is triggered if the voltage has crossed a programmable minimum
91 The driver supports automatic fan control mode known as Thermal Cruise.
92 In this mode, the chip attempts to keep the measured temperature in a
93 predefined temperature range. If the temperature goes out of range, fan
94 is driven slower/faster to reach the predefined range again.
96 The mode works for fan1-fan6.
101 name - this is a standard hwmon device entry, it contains the name of
102 the device (see the prefix in the list of supported devices at
103 the top of this file)
105 pwm[1-6] - this file stores PWM duty cycle or DC value (fan speed) in range:
106 0 (stop) to 255 (full)
108 pwm[1-6]_enable - this file controls mode of fan/temperature control:
109 * 0 Fan control disabled (fans set to maximum speed)
110 * 1 Manual mode, write to pwm file any value 0-255 (full speed)
111 * 2 "Thermal Cruise" mode
112 * 3 "Fan Speed Cruise" mode
113 * 4 "Smart Fan III" mode (NCT6775F only)
114 * 5 "Smart Fan IV" mode
116 pwm[1-6]_mode - controls if output is PWM or DC level
117 * 0 DC output (0 - 12v)
120 Common fan control attributes
121 -----------------------------
123 pwm[1-6]_temp_sel Temperature source. Value is temperature sensor index.
124 For example, select '1' for temp1_input.
125 pwm[1-6]_weight_temp_sel
126 Secondary temperature source. Value is temperature
127 sensor index. For example, select '1' for temp1_input.
128 pwm[1-6]_weight_enable Set to 1 to enable secondary temperature control.
130 If secondary temperature functionality is enabled, it is controlled with the
131 following attributes.
133 pwm[1-6]_weight_duty_step
135 pwm[1-6]_weight_temp_step
136 Temperature step size. With each step over
137 temp_step_base, the value of weight_duty_step is added
138 to the current pwm value.
139 pwm[1-6]_weight_temp_step_base
140 Temperature at which secondary temperature control kicks
142 pwm[1-6]_weight_temp_step_tol
143 Temperature step tolerance or hysteresis. This is a
147 Thermal Cruise mode (2)
148 -----------------------
150 If the temperature is in the range defined by:
152 pwm[1-6]_target Target temperature, unit millidegree Celsius
154 pwm[1-6]_auto_temp1_hyst
155 Hysteresis, unit millidegree Celsius
156 Hysteresis value is relative to pwm[1-6]_auto_temp1.
158 there are no changes to fan speed. Once the temperature leaves the interval,
159 fan speed increases (temp is higher) or decreases if lower than desired,
160 using the following steps and times.
162 pwm[1-6]_start_output fan pwm start value (range 1 - 255), to start fan
163 when the temperature is above defined range.
164 pwm[1-6]_stop_output lowest fan pwm (range 1 - 255) if temperature is below
166 pwm[1-6]_stop_output_enable
167 Set to 1 to enable pwm[1-6]_stop_output. If disabled
168 (set to 0), the fan will stop if the temperature is
169 below the defined range.
170 pwm[1-6]_step_up_time milliseconds [ms] before fan speed is increased
171 pwm[1-6]_step_down_time milliseconds [ms] before fan speed is decreased
172 pwm[1-6]_stop_time how many milliseconds [ms] must elapse to switch
173 corresponding fan off (when the temperature was below
176 Speed Cruise mode (3)
177 ---------------------
179 This modes tries to keep the fan speed constant.
180 Untested; use at your own risk.
182 Smart Fan IV mode (5)
183 ---------------------
185 The fan is regulated to maintain a target temperature. There are five data
186 points. Subsequent data points should be set to higher temperatures and higher
187 pwm values to achieve higher fan speeds with increasing temperature. The last
188 data point reflects critical temperature mode, in which the fans should run at
191 pwm[1-6]_auto_point[1-6]_pwm
192 pwm value to be set if temperature reaches matching
194 pwm[1-6]_auto_point[1-6]_temp
195 Temperature at which the matching pwm is enabled.
196 pwm[1-6]_step_up_time milliseconds [ms] before fan speed is increased
197 pwm[1-6]_step_down_time milliseconds [ms] before fan speed is decreased
203 On various ASUS boards with NCT6776F, it appears that CPUTIN is not really
204 connected to anything and floats, or that it is connected to some non-standard
205 temperature measurement device. As a result, the temperature reported on CPUTIN
206 will not reflect a usable value. It often reports unreasonably high
207 temperatures, and in some cases the reported temperature declines if the actual
208 temperature increases (similar to the raw PECI temperature value - see PECI
209 specification for details). CPUTIN should therefore be be ignored on ASUS
210 boards. The CPU temperature on ASUS boards is reported from PECI 0.
212 Also, there have been reports that not all fan speeds are reported on at least
213 some ASUS boards. P9X79 WS is one example, where fan speed is only reported
214 for two of the fans on the board.
216 Note that ASUS does not support Linux on desktop boards (this appears to be
217 official ASUS policy) and does not release board specifications, so there is
218 nothing we can do to improve support for such boards unless we get board
219 specifications or a detailed description on how to control the fans on the
225 After a suspend/resume cycle, all fan control settings are restored to the BIOS