1 Kernel driver NCT6775 2 ===================== 3 4 .. note:: 5 6 This driver supersedes the NCT6775F and NCT6776F support in the W83627EHF 7 driver. 8 9 Supported 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 91 Authors: 92 93 Guenter Roeck <linux@roeck-us.net> 94 95 Description 96 ----------- 97 98 This driver implements support for the Nuvoton NCT6775F, NCT6776F, and NCT6779D 99 and compatible super I/O chips. 100 101 The chips support up to 25 temperature monitoring sources. Up to 6 of those are 102 direct temperature sensor inputs, the others are special sources such as PECI, 103 PCH, and SMBUS. Depending on the chip type, 2 to 6 of the temperature sources 104 can be monitored and compared against minimum, maximum, and critical 105 temperatures. The driver reports up to 10 of the temperatures to the user. 106 There are 4 to 5 fan rotation speed sensors, 8 to 15 analog voltage sensors, 107 one VID, alarms with beep warnings (control unimplemented), and some automatic 108 fan regulation strategies (plus manual fan control mode). 109 110 The temperature sensor sources on all chips are configurable. The configured 111 source for each of the temperature sensors is provided in tempX_label. 112 113 Temperatures are measured in degrees Celsius and measurement resolution is 114 either 1 degC or 0.5 degC, depending on the temperature source and 115 configuration. An alarm is triggered when the temperature gets higher than 116 the high limit; it stays on until the temperature falls below the hysteresis 117 value. Alarms are only supported for temp1 to temp6, depending on the chip type. 118 119 Fan rotation speeds are reported in RPM (rotations per minute). An alarm is 120 triggered if the rotation speed has dropped below a programmable limit. On 121 NCT6775F, fan readings can be divided by a programmable divider (1, 2, 4, 8, 122 16, 32, 64 or 128) to give the readings more range or accuracy; the other chips 123 do not have a fan speed divider. The driver sets the most suitable fan divisor 124 itself; specifically, it increases the divider value each time a fan speed 125 reading returns an invalid value, and it reduces it if the fan speed reading 126 is lower than optimal. Some fans might not be present because they share pins 127 with other functions. 128 129 Voltage sensors (also known as IN sensors) report their values in millivolts. 130 An alarm is triggered if the voltage has crossed a programmable minimum 131 or maximum limit. 132 133 The driver supports automatic fan control mode known as Thermal Cruise. 134 In this mode, the chip attempts to keep the measured temperature in a 135 predefined temperature range. If the temperature goes out of range, fan 136 is driven slower/faster to reach the predefined range again. 137 138 The mode works for fan1-fan5. 139 140 sysfs attributes 141 ---------------- 142 143 pwm[1-7] 144 - this file stores PWM duty cycle or DC value (fan speed) in range: 145 146 0 (lowest speed) to 255 (full) 147 148 pwm[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 157 158 pwm[1-7]_mode 159 - controls if output is PWM or DC level 160 161 * 0 DC output 162 * 1 PWM output 163 164 Common fan control attributes 165 ----------------------------- 166 167 pwm[1-7]_temp_sel 168 Temperature source. Value is temperature sensor index. 169 For example, select '1' for temp1_input. 170 171 pwm[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. 175 176 If secondary temperature functionality is enabled, it is controlled with the 177 following attributes. 178 179 pwm[1-7]_weight_duty_step 180 Duty step size. 181 182 pwm[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. 186 187 pwm[1-7]_weight_temp_step_base 188 Temperature at which secondary temperature control kicks 189 in. 190 191 pwm[1-7]_weight_temp_step_tol 192 Temperature step tolerance. 193 194 Thermal Cruise mode (2) 195 ----------------------- 196 197 If the temperature is in the range defined by: 198 199 pwm[1-7]_target_temp 200 Target temperature, unit millidegree Celsius 201 (range 0 - 127000) 202 203 pwm[1-7]_temp_tolerance 204 Target temperature tolerance, unit millidegree Celsius 205 206 There are no changes to fan speed. Once the temperature leaves the interval, fan 207 speed increases (if temperature is higher that desired) or decreases (if 208 temperature is lower than desired), using the following limits and time 209 intervals. 210 211 pwm[1-7]_start 212 fan pwm start value (range 1 - 255), to start fan 213 when the temperature is above defined range. 214 215 pwm[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. 219 220 pwm[1-7]_step_up_time 221 milliseconds before fan speed is increased 222 223 pwm[1-7]_step_down_time 224 milliseconds before fan speed is decreased 225 226 pwm[1-7]_stop_time 227 how many milliseconds must elapse to switch 228 corresponding fan off (when the temperature was below 229 defined range). 230 231 Speed Cruise mode (3) 232 --------------------- 233 234 This modes tries to keep the fan speed constant. 235 236 fan[1-7]_target 237 Target fan speed 238 239 fan[1-7]_tolerance 240 Target speed tolerance 241 242 243 Untested; use at your own risk. 244 245 Smart Fan IV mode (5) 246 --------------------- 247 248 This mode offers multiple slopes to control the fan speed. The slopes can be 249 controlled by setting the pwm and temperature attributes. When the temperature 250 rises, the chip will calculate the DC/PWM output based on the current slope. 251 There are up to seven data points depending on the chip type. Subsequent data 252 points should be set to higher temperatures and higher pwm values to achieve 253 higher fan speeds with increasing temperature. The last data point reflects 254 critical temperature mode, in which the fans should run at full speed. 255 256 pwm[1-7]_auto_point[1-7]_pwm 257 pwm value to be set if temperature reaches matching 258 temperature range. 259 260 pwm[1-7]_auto_point[1-7]_temp 261 Temperature over which the matching pwm is enabled. 262 263 pwm[1-7]_temp_tolerance 264 Temperature tolerance, unit millidegree Celsius 265 266 pwm[1-7]_crit_temp_tolerance 267 Temperature tolerance for critical temperature, 268 unit millidegree Celsius 269 270 pwm[1-7]_step_up_time 271 milliseconds before fan speed is increased 272 273 pwm[1-7]_step_down_time 274 milliseconds before fan speed is decreased 275 276 Usage Notes 277 ----------- 278 279 On various ASUS boards with NCT6776F, it appears that CPUTIN is not really 280 connected to anything and floats, or that it is connected to some non-standard 281 temperature measurement device. As a result, the temperature reported on CPUTIN 282 will not reflect a usable value. It often reports unreasonably high 283 temperatures, and in some cases the reported temperature declines if the actual 284 temperature increases (similar to the raw PECI temperature value - see PECI 285 specification for details). CPUTIN should therefore be ignored on ASUS 286 boards. The CPU temperature on ASUS boards is reported from PECI 0 or TSI 0. 287 288 NCT6796D-S and NCT6799D-R chips are very similar and their chip_id indicates 289 they are different versions. This driver treats them the same way.
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