1Kernel driver NCT6775 2===================== 3 4.. note:: 5 6 This driver supersedes the NCT6775F and NCT6776F support in the W83627EHF 7 driver. 8 9Supported chips: 10 11 * Nuvoton NCT6102D/NCT6104D/NCT6106D 12 13 Prefix: 'nct6106' 14 15 Addresses scanned: ISA address retrieved from Super I/O registers 16 17 Datasheet: Available from the Nuvoton web site 18 19 * Nuvoton NCT5572D/NCT6771F/NCT6772F/NCT6775F/W83677HG-I 20 21 Prefix: 'nct6775' 22 23 Addresses scanned: ISA address retrieved from Super I/O registers 24 25 Datasheet: Available from Nuvoton upon request 26 27 * Nuvoton NCT5573D/NCT5577D/NCT6776D/NCT6776F 28 29 Prefix: 'nct6776' 30 31 Addresses scanned: ISA address retrieved from Super I/O registers 32 33 Datasheet: Available from Nuvoton upon request 34 35 * Nuvoton NCT5532D/NCT6779D 36 37 Prefix: 'nct6779' 38 39 Addresses scanned: ISA address retrieved from Super I/O registers 40 41 Datasheet: Available from Nuvoton upon request 42 43 * Nuvoton NCT6791D 44 45 Prefix: 'nct6791' 46 47 Addresses scanned: ISA address retrieved from Super I/O registers 48 49 Datasheet: Available from Nuvoton upon request 50 51 * Nuvoton NCT6792D 52 53 Prefix: 'nct6792' 54 55 Addresses scanned: ISA address retrieved from Super I/O registers 56 57 Datasheet: Available from Nuvoton upon request 58 59 * Nuvoton NCT6793D 60 61 Prefix: 'nct6793' 62 63 Addresses scanned: ISA address retrieved from Super I/O registers 64 65 Datasheet: Available from Nuvoton upon request 66 67 * Nuvoton NCT6795D 68 69 Prefix: 'nct6795' 70 71 Addresses scanned: ISA address retrieved from Super I/O registers 72 73 Datasheet: Available from Nuvoton upon request 74 75 * Nuvoton NCT6796D 76 77 Prefix: 'nct6796' 78 79 Addresses scanned: ISA address retrieved from Super I/O registers 80 81 Datasheet: Available from Nuvoton upon request 82 83 * Nuvoton NCT6796D-S/NCT6799D-R 84 85 Prefix: 'nct6799' 86 87 Addresses scanned: ISA address retrieved from Super I/O registers 88 89 Datasheet: Available from Nuvoton upon request 90 91Authors: 92 93 Guenter Roeck <linux@roeck-us.net> 94 95Description 96----------- 97 98This driver implements support for the Nuvoton NCT6775F, NCT6776F, and NCT6779D 99and compatible super I/O chips. 100 101The chips support up to 25 temperature monitoring sources. Up to 6 of those are 102direct 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 sources 104can be monitored and compared against minimum, maximum, and critical 105temperatures. 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 automatic 108fan regulation strategies (plus manual fan control mode). 109 110The temperature sensor sources on all chips are configurable. The configured 111source for each of the temperature sensors is provided in tempX_label. 112 113Temperatures are measured in degrees Celsius and measurement resolution is 114either 1 degC or 0.5 degC, depending on the temperature source and 115configuration. An alarm is triggered when the temperature gets higher than 116the high limit; it stays on until the temperature falls below the hysteresis 117value. 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 is 120triggered if the rotation speed has dropped below a programmable limit. On 121NCT6775F, 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 chips 123do not have a fan speed divider. The driver sets the most suitable fan divisor 124itself; specifically, it increases the divider value each time a fan speed 125reading returns an invalid value, and it reduces it if the fan speed reading 126is lower than optimal. Some fans might not be present because they share pins 127with 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 minimum 131or 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 a 135predefined temperature range. If the temperature goes out of range, fan 136is driven slower/faster to reach the predefined range again. 137 138The mode works for fan1-fan5. 139 140sysfs attributes 141---------------- 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]_enable 149 - 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 0-255 153 * 2 "Thermal Cruise" mode 154 * 3 "Fan Speed Cruise" mode 155 * 4 "Smart Fan III" mode (NCT6775F only) 156 * 5 "Smart Fan IV" mode 157 158pwm[1-7]_mode 159 - controls if output is PWM or DC level 160 161 * 0 DC output 162 * 1 PWM output 163 164Common fan control attributes 165----------------------------- 166 167pwm[1-7]_temp_sel 168 Temperature source. Value is temperature sensor index. 169 For example, select '1' for temp1_input. 170 171pwm[1-7]_weight_temp_sel 172 Secondary temperature source. Value is temperature 173 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 the 177following attributes. 178 179pwm[1-7]_weight_duty_step 180 Duty step size. 181 182pwm[1-7]_weight_temp_step 183 Temperature step size. With each step over 184 temp_step_base, the value of weight_duty_step is added 185 to the current pwm value. 186 187pwm[1-7]_weight_temp_step_base 188 Temperature at which secondary temperature control kicks 189 in. 190 191pwm[1-7]_weight_temp_step_tol 192 Temperature step tolerance. 193 194Thermal Cruise mode (2) 195----------------------- 196 197If the temperature is in the range defined by: 198 199pwm[1-7]_target_temp 200 Target temperature, unit millidegree Celsius 201 (range 0 - 127000) 202 203pwm[1-7]_temp_tolerance 204 Target temperature tolerance, unit millidegree Celsius 205 206There are no changes to fan speed. Once the temperature leaves the interval, fan 207speed increases (if temperature is higher that desired) or decreases (if 208temperature is lower than desired), using the following limits and time 209intervals. 210 211pwm[1-7]_start 212 fan pwm start value (range 1 - 255), to start fan 213 when the temperature is above defined range. 214 215pwm[1-7]_floor 216 lowest fan pwm (range 0 - 255) if temperature is below 217 the defined range. If set to 0, the fan is expected to 218 stop if the temperature is below the defined range. 219 220pwm[1-7]_step_up_time 221 milliseconds before fan speed is increased 222 223pwm[1-7]_step_down_time 224 milliseconds before fan speed is decreased 225 226pwm[1-7]_stop_time 227 how many milliseconds must elapse to switch 228 corresponding fan off (when the temperature was below 229 defined range). 230 231Speed Cruise mode (3) 232--------------------- 233 234This modes tries to keep the fan speed constant. 235 236fan[1-7]_target 237 Target fan speed 238 239fan[1-7]_tolerance 240 Target speed tolerance 241 242 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 be 249controlled by setting the pwm and temperature attributes. When the temperature 250rises, 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 data 252points should be set to higher temperatures and higher pwm values to achieve 253higher fan speeds with increasing temperature. The last data point reflects 254critical temperature mode, in which the fans should run at full speed. 255 256pwm[1-7]_auto_point[1-7]_pwm 257 pwm value to be set if temperature reaches matching 258 temperature range. 259 260pwm[1-7]_auto_point[1-7]_temp 261 Temperature over which the matching pwm is enabled. 262 263pwm[1-7]_temp_tolerance 264 Temperature tolerance, unit millidegree Celsius 265 266pwm[1-7]_crit_temp_tolerance 267 Temperature tolerance for critical temperature, 268 unit millidegree Celsius 269 270pwm[1-7]_step_up_time 271 milliseconds before fan speed is increased 272 273pwm[1-7]_step_down_time 274 milliseconds before fan speed is decreased 275 276Usage Notes 277----------- 278 279On various ASUS boards with NCT6776F, it appears that CPUTIN is not really 280connected to anything and floats, or that it is connected to some non-standard 281temperature measurement device. As a result, the temperature reported on CPUTIN 282will not reflect a usable value. It often reports unreasonably high 283temperatures, and in some cases the reported temperature declines if the actual 284temperature increases (similar to the raw PECI temperature value - see PECI 285specification for details). CPUTIN should therefore be ignored on ASUS 286boards. 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 indicates 289they are different versions. This driver treats them the same way. 290