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1Kernel driver NCT67752=====================3 4.. note::5 6 This driver supersedes the NCT6775F and NCT6776F support in the W83627EHF7 driver.8 9Supported chips:10 11 * Nuvoton NCT6102D/NCT6104D/NCT6106D12 13 Prefix: 'nct6106'14 15 Addresses scanned: ISA address retrieved from Super I/O registers16 17 Datasheet: Available from the Nuvoton web site18 19 * Nuvoton NCT5572D/NCT6771F/NCT6772F/NCT6775F/W83677HG-I20 21 Prefix: 'nct6775'22 23 Addresses scanned: ISA address retrieved from Super I/O registers24 25 Datasheet: Available from Nuvoton upon request26 27 * Nuvoton NCT5573D/NCT5577D/NCT6776D/NCT6776F28 29 Prefix: 'nct6776'30 31 Addresses scanned: ISA address retrieved from Super I/O registers32 33 Datasheet: Available from Nuvoton upon request34 35 * Nuvoton NCT5532D/NCT6779D36 37 Prefix: 'nct6779'38 39 Addresses scanned: ISA address retrieved from Super I/O registers40 41 Datasheet: Available from Nuvoton upon request42 43 * Nuvoton NCT6791D44 45 Prefix: 'nct6791'46 47 Addresses scanned: ISA address retrieved from Super I/O registers48 49 Datasheet: Available from Nuvoton upon request50 51 * Nuvoton NCT6792D52 53 Prefix: 'nct6792'54 55 Addresses scanned: ISA address retrieved from Super I/O registers56 57 Datasheet: Available from Nuvoton upon request58 59 * Nuvoton NCT6793D60 61 Prefix: 'nct6793'62 63 Addresses scanned: ISA address retrieved from Super I/O registers64 65 Datasheet: Available from Nuvoton upon request66 67 * Nuvoton NCT6795D68 69 Prefix: 'nct6795'70 71 Addresses scanned: ISA address retrieved from Super I/O registers72 73 Datasheet: Available from Nuvoton upon request74 75 * Nuvoton NCT6796D76 77 Prefix: 'nct6796'78 79 Addresses scanned: ISA address retrieved from Super I/O registers80 81 Datasheet: Available from Nuvoton upon request82 83 * Nuvoton NCT6796D-S/NCT6799D-R84 85 Prefix: 'nct6799'86 87 Addresses scanned: ISA address retrieved from Super I/O registers88 89 Datasheet: Available from Nuvoton upon request90 91Authors:92 93 Guenter Roeck <linux@roeck-us.net>94 95Description96-----------97 98This driver implements support for the Nuvoton NCT6775F, NCT6776F, and NCT6779D99and compatible super I/O chips.100 101The chips support up to 25 temperature monitoring sources. Up to 6 of those are102direct temperature sensor inputs, the others are special sources such as PECI,103PCH, and SMBUS. Depending on the chip type, 2 to 6 of the temperature sources104can be monitored and compared against minimum, maximum, and critical105temperatures. The driver reports up to 10 of the temperatures to the user.106There are 4 to 5 fan rotation speed sensors, 8 to 15 analog voltage sensors,107one VID, alarms with beep warnings (control unimplemented), and some automatic108fan regulation strategies (plus manual fan control mode).109 110The temperature sensor sources on all chips are configurable. The configured111source for each of the temperature sensors is provided in tempX_label.112 113Temperatures are measured in degrees Celsius and measurement resolution is114either 1 degC or 0.5 degC, depending on the temperature source and115configuration. An alarm is triggered when the temperature gets higher than116the high limit; it stays on until the temperature falls below the hysteresis117value. Alarms are only supported for temp1 to temp6, depending on the chip type.118 119Fan rotation speeds are reported in RPM (rotations per minute). An alarm is120triggered if the rotation speed has dropped below a programmable limit. On121NCT6775F, fan readings can be divided by a programmable divider (1, 2, 4, 8,12216, 32, 64 or 128) to give the readings more range or accuracy; the other chips123do not have a fan speed divider. The driver sets the most suitable fan divisor124itself; specifically, it increases the divider value each time a fan speed125reading returns an invalid value, and it reduces it if the fan speed reading126is lower than optimal. Some fans might not be present because they share pins127with other functions.128 129Voltage sensors (also known as IN sensors) report their values in millivolts.130An alarm is triggered if the voltage has crossed a programmable minimum131or maximum limit.132 133The driver supports automatic fan control mode known as Thermal Cruise.134In this mode, the chip attempts to keep the measured temperature in a135predefined temperature range. If the temperature goes out of range, fan136is driven slower/faster to reach the predefined range again.137 138The mode works for fan1-fan5.139 140sysfs attributes141----------------142 143pwm[1-7]144 - this file stores PWM duty cycle or DC value (fan speed) in range:145 146 0 (lowest speed) to 255 (full)147 148pwm[1-7]_enable149 - this file controls mode of fan/temperature control:150 151 * 0 Fan control disabled (fans set to maximum speed)152 * 1 Manual mode, write to pwm[0-5] any value 0-255153 * 2 "Thermal Cruise" mode154 * 3 "Fan Speed Cruise" mode155 * 4 "Smart Fan III" mode (NCT6775F only)156 * 5 "Smart Fan IV" mode157 158pwm[1-7]_mode159 - controls if output is PWM or DC level160 161 * 0 DC output162 * 1 PWM output163 164Common fan control attributes165-----------------------------166 167pwm[1-7]_temp_sel168 Temperature source. Value is temperature sensor index.169 For example, select '1' for temp1_input.170 171pwm[1-7]_weight_temp_sel172 Secondary temperature source. Value is temperature173 sensor index. For example, select '1' for temp1_input.174 Set to 0 to disable secondary temperature control.175 176If secondary temperature functionality is enabled, it is controlled with the177following attributes.178 179pwm[1-7]_weight_duty_step180 Duty step size.181 182pwm[1-7]_weight_temp_step183 Temperature step size. With each step over184 temp_step_base, the value of weight_duty_step is added185 to the current pwm value.186 187pwm[1-7]_weight_temp_step_base188 Temperature at which secondary temperature control kicks189 in.190 191pwm[1-7]_weight_temp_step_tol192 Temperature step tolerance.193 194Thermal Cruise mode (2)195-----------------------196 197If the temperature is in the range defined by:198 199pwm[1-7]_target_temp200 Target temperature, unit millidegree Celsius201 (range 0 - 127000)202 203pwm[1-7]_temp_tolerance204 Target temperature tolerance, unit millidegree Celsius205 206There are no changes to fan speed. Once the temperature leaves the interval, fan207speed increases (if temperature is higher that desired) or decreases (if208temperature is lower than desired), using the following limits and time209intervals.210 211pwm[1-7]_start212 fan pwm start value (range 1 - 255), to start fan213 when the temperature is above defined range.214 215pwm[1-7]_floor216 lowest fan pwm (range 0 - 255) if temperature is below217 the defined range. If set to 0, the fan is expected to218 stop if the temperature is below the defined range.219 220pwm[1-7]_step_up_time221 milliseconds before fan speed is increased222 223pwm[1-7]_step_down_time224 milliseconds before fan speed is decreased225 226pwm[1-7]_stop_time227 how many milliseconds must elapse to switch228 corresponding fan off (when the temperature was below229 defined range).230 231Speed Cruise mode (3)232---------------------233 234This modes tries to keep the fan speed constant.235 236fan[1-7]_target237 Target fan speed238 239fan[1-7]_tolerance240 Target speed tolerance241 242 243Untested; use at your own risk.244 245Smart Fan IV mode (5)246---------------------247 248This mode offers multiple slopes to control the fan speed. The slopes can be249controlled by setting the pwm and temperature attributes. When the temperature250rises, the chip will calculate the DC/PWM output based on the current slope.251There are up to seven data points depending on the chip type. Subsequent data252points should be set to higher temperatures and higher pwm values to achieve253higher fan speeds with increasing temperature. The last data point reflects254critical temperature mode, in which the fans should run at full speed.255 256pwm[1-7]_auto_point[1-7]_pwm257 pwm value to be set if temperature reaches matching258 temperature range.259 260pwm[1-7]_auto_point[1-7]_temp261 Temperature over which the matching pwm is enabled.262 263pwm[1-7]_temp_tolerance264 Temperature tolerance, unit millidegree Celsius265 266pwm[1-7]_crit_temp_tolerance267 Temperature tolerance for critical temperature,268 unit millidegree Celsius269 270pwm[1-7]_step_up_time271 milliseconds before fan speed is increased272 273pwm[1-7]_step_down_time274 milliseconds before fan speed is decreased275 276Usage Notes277-----------278 279On various ASUS boards with NCT6776F, it appears that CPUTIN is not really280connected to anything and floats, or that it is connected to some non-standard281temperature measurement device. As a result, the temperature reported on CPUTIN282will not reflect a usable value. It often reports unreasonably high283temperatures, and in some cases the reported temperature declines if the actual284temperature increases (similar to the raw PECI temperature value - see PECI285specification for details). CPUTIN should therefore be ignored on ASUS286boards. The CPU temperature on ASUS boards is reported from PECI 0 or TSI 0.287 288NCT6796D-S and NCT6799D-R chips are very similar and their chip_id indicates289they are different versions. This driver treats them the same way.290