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 NCT6797D 84 85 Prefix: 'nct6797' 86 87 Addresses scanned: ISA address retrieved from Super I/O registers 88 89 Datasheet: Available from Nuvoton upon request 90 91 * Nuvoton NCT6798D 92 93 Prefix: 'nct6798' 94 95 Addresses scanned: ISA address retrieved from Super I/O registers 96 97 Datasheet: Available from Nuvoton upon request 98 99 * Nuvoton NCT5585D (compatible to NCT6798D) 100 101 Prefix: 'nct6798' 102 103 Addresses scanned: ISA address retrieved from Super I/O registers 104 105 Datasheet: Not available 106 107 * Nuvoton NCT6796D-S/NCT6799D-R 108 109 Prefix: 'nct6799' 110 111 Addresses scanned: ISA address retrieved from Super I/O registers 112 113 Datasheet: Available from Nuvoton upon request 114 115Authors: 116 117 Guenter Roeck <linux@roeck-us.net> 118 119Description 120----------- 121 122This driver implements support for the Nuvoton NCT6775F, NCT6776F, and NCT6779D 123and compatible super I/O chips. 124 125The chips support up to 25 temperature monitoring sources. Up to 6 of those are 126direct temperature sensor inputs, the others are special sources such as PECI, 127PCH, and SMBUS. Depending on the chip type, 2 to 6 of the temperature sources 128can be monitored and compared against minimum, maximum, and critical 129temperatures. The driver reports up to 10 of the temperatures to the user. 130There are 4 to 5 fan rotation speed sensors, 8 to 15 analog voltage sensors, 131one VID, alarms with beep warnings (control unimplemented), and some automatic 132fan regulation strategies (plus manual fan control mode). 133 134The temperature sensor sources on all chips are configurable. The configured 135source for each of the temperature sensors is provided in tempX_label. 136 137Temperatures are measured in degrees Celsius and measurement resolution is 138either 1 degC or 0.5 degC, depending on the temperature source and 139configuration. An alarm is triggered when the temperature gets higher than 140the high limit; it stays on until the temperature falls below the hysteresis 141value. Alarms are only supported for temp1 to temp6, depending on the chip type. 142 143Fan rotation speeds are reported in RPM (rotations per minute). An alarm is 144triggered if the rotation speed has dropped below a programmable limit. On 145NCT6775F, fan readings can be divided by a programmable divider (1, 2, 4, 8, 14616, 32, 64 or 128) to give the readings more range or accuracy; the other chips 147do not have a fan speed divider. The driver sets the most suitable fan divisor 148itself; specifically, it increases the divider value each time a fan speed 149reading returns an invalid value, and it reduces it if the fan speed reading 150is lower than optimal. Some fans might not be present because they share pins 151with other functions. 152 153Voltage sensors (also known as IN sensors) report their values in millivolts. 154An alarm is triggered if the voltage has crossed a programmable minimum 155or maximum limit. 156 157The driver supports automatic fan control mode known as Thermal Cruise. 158In this mode, the chip attempts to keep the measured temperature in a 159predefined temperature range. If the temperature goes out of range, fan 160is driven slower/faster to reach the predefined range again. 161 162The mode works for fan1-fan5. 163 164sysfs attributes 165---------------- 166 167pwm[1-7] 168 - this file stores PWM duty cycle or DC value (fan speed) in range: 169 170 0 (lowest speed) to 255 (full) 171 172pwm[1-7]_enable 173 - this file controls mode of fan/temperature control: 174 175 * 0 Fan control disabled (fans set to maximum speed) 176 * 1 Manual mode, write to pwm[0-5] any value 0-255 177 * 2 "Thermal Cruise" mode 178 * 3 "Fan Speed Cruise" mode 179 * 4 "Smart Fan III" mode (NCT6775F only) 180 * 5 "Smart Fan IV" mode 181 182pwm[1-7]_mode 183 - controls if output is PWM or DC level 184 185 * 0 DC output 186 * 1 PWM output 187 188Common fan control attributes 189----------------------------- 190 191pwm[1-7]_temp_sel 192 Temperature source. Value is temperature sensor index. 193 For example, select '1' for temp1_input. 194 195pwm[1-7]_weight_temp_sel 196 Secondary temperature source. Value is temperature 197 sensor index. For example, select '1' for temp1_input. 198 Set to 0 to disable secondary temperature control. 199 200If secondary temperature functionality is enabled, it is controlled with the 201following attributes. 202 203pwm[1-7]_weight_duty_step 204 Duty step size. 205 206pwm[1-7]_weight_temp_step 207 Temperature step size. With each step over 208 temp_step_base, the value of weight_duty_step is added 209 to the current pwm value. 210 211pwm[1-7]_weight_temp_step_base 212 Temperature at which secondary temperature control kicks 213 in. 214 215pwm[1-7]_weight_temp_step_tol 216 Temperature step tolerance. 217 218Thermal Cruise mode (2) 219----------------------- 220 221If the temperature is in the range defined by: 222 223pwm[1-7]_target_temp 224 Target temperature, unit millidegree Celsius 225 (range 0 - 127000) 226 227pwm[1-7]_temp_tolerance 228 Target temperature tolerance, unit millidegree Celsius 229 230There are no changes to fan speed. Once the temperature leaves the interval, fan 231speed increases (if temperature is higher that desired) or decreases (if 232temperature is lower than desired), using the following limits and time 233intervals. 234 235pwm[1-7]_start 236 fan pwm start value (range 1 - 255), to start fan 237 when the temperature is above defined range. 238 239pwm[1-7]_floor 240 lowest fan pwm (range 0 - 255) if temperature is below 241 the defined range. If set to 0, the fan is expected to 242 stop if the temperature is below the defined range. 243 244pwm[1-7]_step_up_time 245 milliseconds before fan speed is increased 246 247pwm[1-7]_step_down_time 248 milliseconds before fan speed is decreased 249 250pwm[1-7]_stop_time 251 how many milliseconds must elapse to switch 252 corresponding fan off (when the temperature was below 253 defined range). 254 255Speed Cruise mode (3) 256--------------------- 257 258This modes tries to keep the fan speed constant. 259 260fan[1-7]_target 261 Target fan speed 262 263fan[1-7]_tolerance 264 Target speed tolerance 265 266 267Untested; use at your own risk. 268 269Smart Fan IV mode (5) 270--------------------- 271 272This mode offers multiple slopes to control the fan speed. The slopes can be 273controlled by setting the pwm and temperature attributes. When the temperature 274rises, the chip will calculate the DC/PWM output based on the current slope. 275There are up to seven data points depending on the chip type. Subsequent data 276points should be set to higher temperatures and higher pwm values to achieve 277higher fan speeds with increasing temperature. The last data point reflects 278critical temperature mode, in which the fans should run at full speed. 279 280pwm[1-7]_auto_point[1-7]_pwm 281 pwm value to be set if temperature reaches matching 282 temperature range. 283 284pwm[1-7]_auto_point[1-7]_temp 285 Temperature over which the matching pwm is enabled. 286 287pwm[1-7]_temp_tolerance 288 Temperature tolerance, unit millidegree Celsius 289 290pwm[1-7]_crit_temp_tolerance 291 Temperature tolerance for critical temperature, 292 unit millidegree Celsius 293 294pwm[1-7]_step_up_time 295 milliseconds before fan speed is increased 296 297pwm[1-7]_step_down_time 298 milliseconds before fan speed is decreased 299 300Usage Notes 301----------- 302 303On various ASUS boards with NCT6776F, it appears that CPUTIN is not really 304connected to anything and floats, or that it is connected to some non-standard 305temperature measurement device. As a result, the temperature reported on CPUTIN 306will not reflect a usable value. It often reports unreasonably high 307temperatures, and in some cases the reported temperature declines if the actual 308temperature increases (similar to the raw PECI temperature value - see PECI 309specification for details). CPUTIN should therefore be ignored on ASUS 310boards. The CPU temperature on ASUS boards is reported from PECI 0 or TSI 0. 311 312NCT6796D-S and NCT6799D-R chips are very similar and their chip_id indicates 313they are different versions. This driver treats them the same way. 314