blob: f0dd3d2fec96da61b56d010c19a83755d320f52f [file] [log] [blame]
Guenter Roeck9de2e2e2012-05-20 19:29:48 -07001Note
2====
3
4This driver supersedes the NCT6775F and NCT6776F support in the W83627EHF
5driver.
6
7Kernel driver NCT6775
8=====================
9
10Supported chips:
Guenter Roeckb6e6dd82014-11-17 06:43:55 -080011 * Nuvoton NCT6102D/NCT6104D/NCT6106D
12 Prefix: 'nct6106'
13 Addresses scanned: ISA address retrieved from Super I/O registers
14 Datasheet: Available from the Nuvoton web site
Guenter Roeck2c7fd302013-04-02 08:53:19 -070015 * Nuvoton NCT5572D/NCT6771F/NCT6772F/NCT6775F/W83677HG-I
Guenter Roeck9de2e2e2012-05-20 19:29:48 -070016 Prefix: 'nct6775'
17 Addresses scanned: ISA address retrieved from Super I/O registers
18 Datasheet: Available from Nuvoton upon request
Guenter Roeckb6e6dd82014-11-17 06:43:55 -080019 * Nuvoton NCT5573D/NCT5577D/NCT6776D/NCT6776F
Guenter Roeck9de2e2e2012-05-20 19:29:48 -070020 Prefix: 'nct6776'
21 Addresses scanned: ISA address retrieved from Super I/O registers
22 Datasheet: Available from Nuvoton upon request
Guenter Roeck2c7fd302013-04-02 08:53:19 -070023 * Nuvoton NCT5532D/NCT6779D
Guenter Roeck9de2e2e2012-05-20 19:29:48 -070024 Prefix: 'nct6779'
25 Addresses scanned: ISA address retrieved from Super I/O registers
26 Datasheet: Available from Nuvoton upon request
Guenter Roeckb6e6dd82014-11-17 06:43:55 -080027 * Nuvoton NCT6791D
28 Prefix: 'nct6791'
29 Addresses scanned: ISA address retrieved from Super I/O registers
30 Datasheet: Available from Nuvoton upon request
Guenter Roeck8aefb932014-11-16 09:50:04 -080031 * Nuvoton NCT6792D
32 Prefix: 'nct6792'
33 Addresses scanned: ISA address retrieved from Super I/O registers
34 Datasheet: Available from Nuvoton upon request
Guenter Roeck9de2e2e2012-05-20 19:29:48 -070035
36Authors:
37 Guenter Roeck <linux@roeck-us.net>
38
39Description
40-----------
41
42This driver implements support for the Nuvoton NCT6775F, NCT6776F, and NCT6779D
Guenter Roeck2c7fd302013-04-02 08:53:19 -070043and compatible super I/O chips.
Guenter Roeck9de2e2e2012-05-20 19:29:48 -070044
45The chips support up to 25 temperature monitoring sources. Up to 6 of those are
46direct temperature sensor inputs, the others are special sources such as PECI,
47PCH, and SMBUS. Depending on the chip type, 2 to 6 of the temperature sources
48can be monitored and compared against minimum, maximum, and critical
49temperatures. The driver reports up to 10 of the temperatures to the user.
50There are 4 to 5 fan rotation speed sensors, 8 to 15 analog voltage sensors,
51one VID, alarms with beep warnings (control unimplemented), and some automatic
52fan regulation strategies (plus manual fan control mode).
53
54The temperature sensor sources on all chips are configurable. The configured
55source for each of the temperature sensors is provided in tempX_label.
56
57Temperatures are measured in degrees Celsius and measurement resolution is
58either 1 degC or 0.5 degC, depending on the temperature source and
59configuration. An alarm is triggered when the temperature gets higher than
60the high limit; it stays on until the temperature falls below the hysteresis
61value. Alarms are only supported for temp1 to temp6, depending on the chip type.
62
63Fan rotation speeds are reported in RPM (rotations per minute). An alarm is
64triggered if the rotation speed has dropped below a programmable limit. On
65NCT6775F, fan readings can be divided by a programmable divider (1, 2, 4, 8,
6616, 32, 64 or 128) to give the readings more range or accuracy; the other chips
67do not have a fan speed divider. The driver sets the most suitable fan divisor
Guenter Roeck1c65dc32012-12-04 07:56:24 -080068itself; specifically, it increases the divider value each time a fan speed
69reading returns an invalid value, and it reduces it if the fan speed reading
70is lower than optimal. Some fans might not be present because they share pins
Guenter Roeck9de2e2e2012-05-20 19:29:48 -070071with other functions.
72
73Voltage sensors (also known as IN sensors) report their values in millivolts.
74An alarm is triggered if the voltage has crossed a programmable minimum
75or maximum limit.
76
77The driver supports automatic fan control mode known as Thermal Cruise.
78In this mode, the chip attempts to keep the measured temperature in a
79predefined temperature range. If the temperature goes out of range, fan
80is driven slower/faster to reach the predefined range again.
81
82The mode works for fan1-fan5.
83
Guenter Roeck77eb5b32012-12-04 08:30:54 -080084sysfs attributes
85----------------
86
87pwm[1-5] - this file stores PWM duty cycle or DC value (fan speed) in range:
88 0 (lowest speed) to 255 (full)
89
90pwm[1-5]_enable - this file controls mode of fan/temperature control:
91 * 0 Fan control disabled (fans set to maximum speed)
92 * 1 Manual mode, write to pwm[0-5] any value 0-255
93 * 2 "Thermal Cruise" mode
94 * 3 "Fan Speed Cruise" mode
95 * 4 "Smart Fan III" mode (NCT6775F only)
96 * 5 "Smart Fan IV" mode
97
98pwm[1-5]_mode - controls if output is PWM or DC level
99 * 0 DC output
100 * 1 PWM output
101
Guenter Roeckcdcaece2012-12-04 09:04:52 -0800102Common fan control attributes
103-----------------------------
104
105pwm[1-5]_temp_sel Temperature source. Value is temperature sensor index.
106 For example, select '1' for temp1_input.
Guenter Roeckbbd8dec2012-12-04 09:08:29 -0800107pwm[1-5]_weight_temp_sel
108 Secondary temperature source. Value is temperature
109 sensor index. For example, select '1' for temp1_input.
110 Set to 0 to disable secondary temperature control.
111
112If secondary temperature functionality is enabled, it is controlled with the
113following attributes.
114
115pwm[1-5]_weight_duty_step
116 Duty step size.
117pwm[1-5]_weight_temp_step
118 Temperature step size. With each step over
119 temp_step_base, the value of weight_duty_step is added
120 to the current pwm value.
121pwm[1-5]_weight_temp_step_base
122 Temperature at which secondary temperature control kicks
123 in.
124pwm[1-5]_weight_temp_step_tol
125 Temperature step tolerance.
Guenter Roeckcdcaece2012-12-04 09:04:52 -0800126
127Thermal Cruise mode (2)
128-----------------------
129
130If the temperature is in the range defined by:
131
132pwm[1-5]_target_temp Target temperature, unit millidegree Celsius
133 (range 0 - 127000)
134pwm[1-5]_temp_tolerance
135 Target temperature tolerance, unit millidegree Celsius
136
137there are no changes to fan speed. Once the temperature leaves the interval, fan
138speed increases (if temperature is higher that desired) or decreases (if
139temperature is lower than desired), using the following limits and time
140intervals.
141
142pwm[1-5]_start fan pwm start value (range 1 - 255), to start fan
143 when the temperature is above defined range.
144pwm[1-5]_floor lowest fan pwm (range 0 - 255) if temperature is below
145 the defined range. If set to 0, the fan is expected to
146 stop if the temperature is below the defined range.
147pwm[1-5]_step_up_time milliseconds before fan speed is increased
148pwm[1-5]_step_down_time milliseconds before fan speed is decreased
149pwm[1-5]_stop_time how many milliseconds must elapse to switch
150 corresponding fan off (when the temperature was below
151 defined range).
152
153Speed Cruise mode (3)
154---------------------
155
156This modes tries to keep the fan speed constant.
157
158fan[1-5]_target Target fan speed
159fan[1-5]_tolerance
160 Target speed tolerance
161
162
163Untested; use at your own risk.
164
165Smart Fan IV mode (5)
166---------------------
167
168This mode offers multiple slopes to control the fan speed. The slopes can be
169controlled by setting the pwm and temperature attributes. When the temperature
170rises, the chip will calculate the DC/PWM output based on the current slope.
171There are up to seven data points depending on the chip type. Subsequent data
172points should be set to higher temperatures and higher pwm values to achieve
173higher fan speeds with increasing temperature. The last data point reflects
174critical temperature mode, in which the fans should run at full speed.
175
176pwm[1-5]_auto_point[1-7]_pwm
177 pwm value to be set if temperature reaches matching
178 temperature range.
179pwm[1-5]_auto_point[1-7]_temp
180 Temperature over which the matching pwm is enabled.
181pwm[1-5]_temp_tolerance
182 Temperature tolerance, unit millidegree Celsius
183pwm[1-5]_crit_temp_tolerance
184 Temperature tolerance for critical temperature,
185 unit millidegree Celsius
186
187pwm[1-5]_step_up_time milliseconds before fan speed is increased
188pwm[1-5]_step_down_time milliseconds before fan speed is decreased
189
Guenter Roeck9de2e2e2012-05-20 19:29:48 -0700190Usage Notes
191-----------
192
193On various ASUS boards with NCT6776F, it appears that CPUTIN is not really
194connected to anything and floats, or that it is connected to some non-standard
195temperature measurement device. As a result, the temperature reported on CPUTIN
196will not reflect a usable value. It often reports unreasonably high
197temperatures, and in some cases the reported temperature declines if the actual
198temperature increases (similar to the raw PECI temperature value - see PECI
199specification for details). CPUTIN should therefore be be ignored on ASUS
200boards. The CPU temperature on ASUS boards is reported from PECI 0.