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9de2e2e8 GR |
1 | Note |
2 | ==== | |
3 | ||
4 | This driver supersedes the NCT6775F and NCT6776F support in the W83627EHF | |
5 | driver. | |
6 | ||
7 | Kernel driver NCT6775 | |
8 | ===================== | |
9 | ||
10 | Supported chips: | |
11 | * Nuvoton NCT6775F/W83667HG-I | |
12 | Prefix: 'nct6775' | |
13 | Addresses scanned: ISA address retrieved from Super I/O registers | |
14 | Datasheet: Available from Nuvoton upon request | |
15 | * Nuvoton NCT6776F | |
16 | Prefix: 'nct6776' | |
17 | Addresses scanned: ISA address retrieved from Super I/O registers | |
18 | Datasheet: Available from Nuvoton upon request | |
19 | * Nuvoton NCT6779D | |
20 | Prefix: 'nct6779' | |
21 | Addresses scanned: ISA address retrieved from Super I/O registers | |
22 | Datasheet: Available from Nuvoton upon request | |
23 | ||
24 | Authors: | |
25 | Guenter Roeck <linux@roeck-us.net> | |
26 | ||
27 | Description | |
28 | ----------- | |
29 | ||
30 | This driver implements support for the Nuvoton NCT6775F, NCT6776F, and NCT6779D | |
31 | super I/O chips. | |
32 | ||
33 | The chips support up to 25 temperature monitoring sources. Up to 6 of those are | |
34 | direct temperature sensor inputs, the others are special sources such as PECI, | |
35 | PCH, and SMBUS. Depending on the chip type, 2 to 6 of the temperature sources | |
36 | can be monitored and compared against minimum, maximum, and critical | |
37 | temperatures. The driver reports up to 10 of the temperatures to the user. | |
38 | There are 4 to 5 fan rotation speed sensors, 8 to 15 analog voltage sensors, | |
39 | one VID, alarms with beep warnings (control unimplemented), and some automatic | |
40 | fan regulation strategies (plus manual fan control mode). | |
41 | ||
42 | The temperature sensor sources on all chips are configurable. The configured | |
43 | source for each of the temperature sensors is provided in tempX_label. | |
44 | ||
45 | Temperatures are measured in degrees Celsius and measurement resolution is | |
46 | either 1 degC or 0.5 degC, depending on the temperature source and | |
47 | configuration. An alarm is triggered when the temperature gets higher than | |
48 | the high limit; it stays on until the temperature falls below the hysteresis | |
49 | value. Alarms are only supported for temp1 to temp6, depending on the chip type. | |
50 | ||
51 | Fan rotation speeds are reported in RPM (rotations per minute). An alarm is | |
52 | triggered if the rotation speed has dropped below a programmable limit. On | |
53 | NCT6775F, fan readings can be divided by a programmable divider (1, 2, 4, 8, | |
54 | 16, 32, 64 or 128) to give the readings more range or accuracy; the other chips | |
55 | do not have a fan speed divider. The driver sets the most suitable fan divisor | |
1c65dc36 GR |
56 | itself; specifically, it increases the divider value each time a fan speed |
57 | reading returns an invalid value, and it reduces it if the fan speed reading | |
58 | is lower than optimal. Some fans might not be present because they share pins | |
9de2e2e8 GR |
59 | with other functions. |
60 | ||
61 | Voltage sensors (also known as IN sensors) report their values in millivolts. | |
62 | An alarm is triggered if the voltage has crossed a programmable minimum | |
63 | or maximum limit. | |
64 | ||
65 | The driver supports automatic fan control mode known as Thermal Cruise. | |
66 | In this mode, the chip attempts to keep the measured temperature in a | |
67 | predefined temperature range. If the temperature goes out of range, fan | |
68 | is driven slower/faster to reach the predefined range again. | |
69 | ||
70 | The mode works for fan1-fan5. | |
71 | ||
77eb5b37 GR |
72 | sysfs attributes |
73 | ---------------- | |
74 | ||
75 | pwm[1-5] - this file stores PWM duty cycle or DC value (fan speed) in range: | |
76 | 0 (lowest speed) to 255 (full) | |
77 | ||
78 | pwm[1-5]_enable - this file controls mode of fan/temperature control: | |
79 | * 0 Fan control disabled (fans set to maximum speed) | |
80 | * 1 Manual mode, write to pwm[0-5] any value 0-255 | |
81 | * 2 "Thermal Cruise" mode | |
82 | * 3 "Fan Speed Cruise" mode | |
83 | * 4 "Smart Fan III" mode (NCT6775F only) | |
84 | * 5 "Smart Fan IV" mode | |
85 | ||
86 | pwm[1-5]_mode - controls if output is PWM or DC level | |
87 | * 0 DC output | |
88 | * 1 PWM output | |
89 | ||
cdcaeceb GR |
90 | Common fan control attributes |
91 | ----------------------------- | |
92 | ||
93 | pwm[1-5]_temp_sel Temperature source. Value is temperature sensor index. | |
94 | For example, select '1' for temp1_input. | |
95 | ||
96 | Thermal Cruise mode (2) | |
97 | ----------------------- | |
98 | ||
99 | If the temperature is in the range defined by: | |
100 | ||
101 | pwm[1-5]_target_temp Target temperature, unit millidegree Celsius | |
102 | (range 0 - 127000) | |
103 | pwm[1-5]_temp_tolerance | |
104 | Target temperature tolerance, unit millidegree Celsius | |
105 | ||
106 | there are no changes to fan speed. Once the temperature leaves the interval, fan | |
107 | speed increases (if temperature is higher that desired) or decreases (if | |
108 | temperature is lower than desired), using the following limits and time | |
109 | intervals. | |
110 | ||
111 | pwm[1-5]_start fan pwm start value (range 1 - 255), to start fan | |
112 | when the temperature is above defined range. | |
113 | pwm[1-5]_floor lowest fan pwm (range 0 - 255) if temperature is below | |
114 | the defined range. If set to 0, the fan is expected to | |
115 | stop if the temperature is below the defined range. | |
116 | pwm[1-5]_step_up_time milliseconds before fan speed is increased | |
117 | pwm[1-5]_step_down_time milliseconds before fan speed is decreased | |
118 | pwm[1-5]_stop_time how many milliseconds must elapse to switch | |
119 | corresponding fan off (when the temperature was below | |
120 | defined range). | |
121 | ||
122 | Speed Cruise mode (3) | |
123 | --------------------- | |
124 | ||
125 | This modes tries to keep the fan speed constant. | |
126 | ||
127 | fan[1-5]_target Target fan speed | |
128 | fan[1-5]_tolerance | |
129 | Target speed tolerance | |
130 | ||
131 | ||
132 | Untested; use at your own risk. | |
133 | ||
134 | Smart Fan IV mode (5) | |
135 | --------------------- | |
136 | ||
137 | This mode offers multiple slopes to control the fan speed. The slopes can be | |
138 | controlled by setting the pwm and temperature attributes. When the temperature | |
139 | rises, the chip will calculate the DC/PWM output based on the current slope. | |
140 | There are up to seven data points depending on the chip type. Subsequent data | |
141 | points should be set to higher temperatures and higher pwm values to achieve | |
142 | higher fan speeds with increasing temperature. The last data point reflects | |
143 | critical temperature mode, in which the fans should run at full speed. | |
144 | ||
145 | pwm[1-5]_auto_point[1-7]_pwm | |
146 | pwm value to be set if temperature reaches matching | |
147 | temperature range. | |
148 | pwm[1-5]_auto_point[1-7]_temp | |
149 | Temperature over which the matching pwm is enabled. | |
150 | pwm[1-5]_temp_tolerance | |
151 | Temperature tolerance, unit millidegree Celsius | |
152 | pwm[1-5]_crit_temp_tolerance | |
153 | Temperature tolerance for critical temperature, | |
154 | unit millidegree Celsius | |
155 | ||
156 | pwm[1-5]_step_up_time milliseconds before fan speed is increased | |
157 | pwm[1-5]_step_down_time milliseconds before fan speed is decreased | |
158 | ||
9de2e2e8 GR |
159 | Usage Notes |
160 | ----------- | |
161 | ||
162 | On various ASUS boards with NCT6776F, it appears that CPUTIN is not really | |
163 | connected to anything and floats, or that it is connected to some non-standard | |
164 | temperature measurement device. As a result, the temperature reported on CPUTIN | |
165 | will not reflect a usable value. It often reports unreasonably high | |
166 | temperatures, and in some cases the reported temperature declines if the actual | |
167 | temperature increases (similar to the raw PECI temperature value - see PECI | |
168 | specification for details). CPUTIN should therefore be be ignored on ASUS | |
169 | boards. The CPU temperature on ASUS boards is reported from PECI 0. |