4 This driver supercedes the NCT6775F and NCT6776F support in the W83627EHF
5 driver. It supports NCT6775F, NCT6776F, and NCT6779D.
7 Preliminary support for NCT6106D is available in the nct6106 git branch.
8 The code in this branch is untested.
12 =======================
17 Addresses scanned: ISA address retrieved from Super I/O registers
18 Datasheet: Available from Nuvoton upon request
19 * Nuvoton NCT6775F/W83667HG-I
21 Addresses scanned: ISA address retrieved from Super I/O registers
22 Datasheet: Available from Nuvoton upon request
25 Addresses scanned: ISA address retrieved from Super I/O registers
26 Datasheet: Available from Nuvoton upon request
29 Addresses scanned: ISA address retrieved from Super I/O registers
30 Datasheet: Available from Nuvoton upon request
33 Guenter Roeck <linux@roeck-us.net>
38 This driver implements support for the Nuvoton NCT6106D, NCT6775F, NCT6776F,
39 and NCT6779D super I/O chips. We will refer to them collectively as Nuvoton
42 The chips implement up to 8 temperature sensors depending on the chip type and
43 configuration. Temperatures used to control fan speed are reported separately.
44 There are 4 to 5 fan rotation speed sensors, 8 to 15 analog voltage sensors,
45 one VID, alarms with beep warnings (control unimplemented), and some automatic
46 fan regulation strategies (plus manual fan control mode).
48 The temperature sensor sources on all chips are configurable. temp4 and higher
49 attributes are only reported if its temperature source differs from the
50 temperature sources of the already reported temperature sensors.
51 The configured source for each of the temperature sensors is provided
54 Temperatures are measured in degrees Celsius and measurement resolution is
55 either 1 degC or 0.5 degC, depending on the temperature source and
56 configuration. An alarm is triggered when the temperature gets higher than
57 the high limit; it stays on until the temperature falls below the hysteresis
58 value. Alarms are only supported for temp1, temp2, and temp3.
60 Fan rotation speeds are reported in RPM (rotations per minute). An alarm is
61 triggered if the rotation speed has dropped below a programmable limit. Fan
62 readings can be divided by a programmable divider (1, 2, 4, 8, 16, 32, 64 or
63 128) to give the readings more range or accuracy. The driver sets the most
64 suitable fan divisor itself. Some fans might not be present because they
65 share pins with other functions.
67 Voltage sensors (also known as IN sensors) report their values in millivolts.
68 An alarm is triggered if the voltage has crossed a programmable minimum
71 The driver supports automatic fan control mode known as Thermal Cruise.
72 In this mode, the chip attempts to keep the measured temperature in a
73 predefined temperature range. If the temperature goes out of range, fan
74 is driven slower/faster to reach the predefined range again.
76 The mode works for fan1-fan5.
81 name - this is a standard hwmon device entry, it contains the name of
82 the device (see the prefix in the list of supported devices at
85 pwm[1-5] - this file stores PWM duty cycle or DC value (fan speed) in range:
86 0 (stop) to 255 (full)
88 pwm[1-5]_enable - this file controls mode of fan/temperature control:
89 * 0 Fan control disabled (fans set to maximum speed)
90 * 1 Manual mode, write to pwm file any value 0-255 (full speed)
91 * 2 "Thermal Cruise" mode
92 * 3 "Fan Speed Cruise" mode
93 * 4 "Smart Fan III" mode (NCT6775F only)
94 * 5 "Smart Fan IV" mode
96 pwm[1-5]_mode - controls if output is PWM or DC level
97 * 0 DC output (0 - 12v)
100 Common fan control attributes
101 -----------------------------
103 pwm[1-5]_temp_sel Temperature source. Value is temperature sensor index.
104 For example, select '1' for temp1_input.
105 pwm[1-5]_weight_temp_sel
106 Secondary temperature source. Value is temperature
107 sensor index. For example, select '1' for temp1_input.
108 pwm[1-5]_weight_enable Set to 1 to enable secondary temperature control.
110 If secondary temperature functionality is enabled, it is controlled with the
111 following attributes.
113 pwm[1-5]_weight_duty_step
115 pwm[1-5]_weight_temp_step
116 Temperature step size. With each step over
117 temp_step_base, the value of weight_duty_step is added
118 to the current pwm value.
119 pwm[1-5]_weight_temp_step_base
120 Temperature at which secondary temperature control kicks
122 pwm[1-5]_weight_temp_step_tol
123 Temperature step tolerance or hysteresis. This is a
127 Thermal Cruise mode (2)
128 -----------------------
130 If the temperature is in the range defined by:
132 pwm[1-5]_target Target temperature, unit millidegree Celsius
134 pwm[1-5]_auto_temp1_hyst
135 Hysteresis, unit millidegree Celsius
136 Hysteresis value is relative to pwm[1-5]_auto_temp1.
138 there are no changes to fan speed. Once the temperature leaves the interval,
139 fan speed increases (temp is higher) or decreases if lower than desired,
140 using the following steps and times.
142 pwm[1-5]_start_output fan pwm start value (range 1 - 255), to start fan
143 when the temperature is above defined range.
144 pwm[1-5]_stop_output lowest fan pwm (range 1 - 255) if temperature is below
146 pwm[1-5]_stop_output_enable
147 Set to 1 to enable pwm[1-5]_stop_output. If disabled
148 (set to 0), the fan will stop if the temperature is
149 below the defined range.
150 pwm[1-5]_step_up_time milliseconds [ms] before fan speed is increased
151 pwm[1-5]_step_down_time milliseconds [ms] before fan speed is decreased
152 pwm[1-5]_stop_time how many milliseconds [ms] must elapse to switch
153 corresponding fan off (when the temperature was below
156 Speed Cruise mode (3)
157 ---------------------
159 This modes tries to keep the fan speed constant.
160 Untested; use at your own risk.
162 Smart Fan IV mode (5)
163 ---------------------
165 The fan is regulated to maintain a target temperature. There are five data
166 points. Subsequent data points should be set to higher temperatures and higher
167 pwm values to achieve higher fan speeds with increasing temperature. The last
168 data point reflects critical temperature mode, in which the fans should run at
171 pwm[1-5]_auto_point[1-5]_pwm
172 pwm value to be set if temperature reaches matching
174 pwm[1-5]_auto_point[1-5]_temp
175 Temperature at which the matching pwm is enabled.
176 pwm[1-5]_step_up_time milliseconds [ms] before fan speed is increased
177 pwm[1-5]_step_down_time milliseconds [ms] before fan speed is decreased
178 pwm[1-5]_step_enable Set to 1 to enable fine grain speed control.
179 If disabled, pwm values will increase or decrease to
180 the values configured in the auto_point_pwm attributes.
181 If enabled, pwm values will be interpolated, resulting
182 in a more fine-grained fan control, resulting in a more
183 fine-grained fan control
189 On various ASUS boards with NCT6776F, it appears that CPUTIN is not really
190 connected to anything and floats, or that it is connected to some non-standard
191 temperature measurement device. As a result, the temperature reported on CPUTIN
192 will not reflect a usable value. It often reports unreasonablyy high
193 temperatures, and in some cases the reported temperature declines if the actual
194 temperature increases (similar to the raw PECI temperature value - see PECI
195 specification for details). CPUTIN should therefore be be ignored on ASUS
196 boards. The CPU temperature on ASUS boards is reported from PECI 0.