w83792d.rst (6296B)
1Kernel driver w83792d 2===================== 3 4Supported chips: 5 6 * Winbond W83792D 7 8 Prefix: 'w83792d' 9 10 Addresses scanned: I2C 0x2c - 0x2f 11 12 Datasheet: http://www.winbond.com.tw 13 14Author: Shane Huang (Winbond) 15Updated: Roger Lucas 16 17 18Module Parameters 19----------------- 20 21* init int 22 (default 1) 23 24 Use 'init=0' to bypass initializing the chip. 25 Try this if your computer crashes when you load the module. 26 27* force_subclients=bus,caddr,saddr,saddr 28 This is used to force the i2c addresses for subclients of 29 a certain chip. Example usage is `force_subclients=0,0x2f,0x4a,0x4b` 30 to force the subclients of chip 0x2f on bus 0 to i2c addresses 31 0x4a and 0x4b. 32 33 34Description 35----------- 36 37This driver implements support for the Winbond W83792AD/D. 38 39Detection of the chip can sometimes be foiled because it can be in an 40internal state that allows no clean access (Bank with ID register is not 41currently selected). If you know the address of the chip, use a 'force' 42parameter; this will put it into a more well-behaved state first. 43 44The driver implements three temperature sensors, seven fan rotation speed 45sensors, nine voltage sensors, and two automatic fan regulation 46strategies called: Smart Fan I (Thermal Cruise mode) and Smart Fan II. 47 48The driver also implements up to seven fan control outputs: pwm1-7. Pwm1-7 49can be configured to PWM output or Analogue DC output via their associated 50pwmX_mode. Outputs pwm4 through pwm7 may or may not be present depending on 51how the W83792AD/D was configured by the BIOS. 52 53Automatic fan control mode is possible only for fan1-fan3. 54 55For all pwmX outputs, a value of 0 means minimum fan speed and a value of 56255 means maximum fan speed. 57 58Temperatures are measured in degrees Celsius and measurement resolution is 1 59degC for temp1 and 0.5 degC for temp2 and temp3. An alarm is triggered when 60the temperature gets higher than the Overtemperature Shutdown value; it stays 61on until the temperature falls below the Hysteresis value. 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. Fan 65readings can be divided by a programmable divider (1, 2, 4, 8, 16, 32, 64 or 66128) to give the readings more range or accuracy. 67 68Voltage sensors (also known as IN sensors) report their values in millivolts. 69An alarm is triggered if the voltage has crossed a programmable minimum 70or maximum limit. 71 72Alarms are provided as output from "realtime status register". Following bits 73are defined: 74 75==== ========== 76bit alarm on 77==== ========== 780 in0 791 in1 802 temp1 813 temp2 824 temp3 835 fan1 846 fan2 857 fan3 868 in2 879 in3 8810 in4 8911 in5 9012 in6 9113 VID change 9214 chassis 9315 fan7 9416 tart1 9517 tart2 9618 tart3 9719 in7 9820 in8 9921 fan4 10022 fan5 10123 fan6 102==== ========== 103 104Tart will be asserted while target temperature cannot be achieved after 3 minutes 105of full speed rotation of corresponding fan. 106 107In addition to the alarms described above, there is a CHAS alarm on the chips 108which triggers if your computer case is open (This one is latched, contrary 109to realtime alarms). 110 111The chips only update values each 3 seconds; reading them more often will 112do no harm, but will return 'old' values. 113 114 115W83792D PROBLEMS 116---------------- 117Known problems: 118 - This driver is only for Winbond W83792D C version device, there 119 are also some motherboards with B version W83792D device. The 120 calculation method to in6-in7(measured value, limits) is a little 121 different between C and B version. C or B version can be identified 122 by CR[0x49h]. 123 - The function of vid and vrm has not been finished, because I'm NOT 124 very familiar with them. Adding support is welcome. 125 - The function of chassis open detection needs more tests. 126 - If you have ASUS server board and chip was not found: Then you will 127 need to upgrade to latest (or beta) BIOS. If it does not help please 128 contact us. 129 130Fan control 131----------- 132 133Manual mode 134----------- 135 136Works as expected. You just need to specify desired PWM/DC value (fan speed) 137in appropriate pwm# file. 138 139Thermal cruise 140-------------- 141 142In this mode, W83792D provides the Smart Fan system to automatically control 143fan speed to keep the temperatures of CPU and the system within specific 144range. At first a wanted temperature and interval must be set. This is done 145via thermal_cruise# file. The tolerance# file serves to create T +- tolerance 146interval. The fan speed will be lowered as long as the current temperature 147remains below the thermal_cruise# +- tolerance# value. Once the temperature 148exceeds the high limit (T+tolerance), the fan will be turned on with a 149specific speed set by pwm# and automatically controlled its PWM duty cycle 150with the temperature varying. Three conditions may occur: 151 152(1) If the temperature still exceeds the high limit, PWM duty 153cycle will increase slowly. 154 155(2) If the temperature goes below the high limit, but still above the low 156limit (T-tolerance), the fan speed will be fixed at the current speed because 157the temperature is in the target range. 158 159(3) If the temperature goes below the low limit, PWM duty cycle will decrease 160slowly to 0 or a preset stop value until the temperature exceeds the low 161limit. (The preset stop value handling is not yet implemented in driver) 162 163Smart Fan II 164------------ 165 166W83792D also provides a special mode for fan. Four temperature points are 167available. When related temperature sensors detects the temperature in preset 168temperature region (sf2_point@_fan# +- tolerance#) it will cause fans to run 169on programmed value from sf2_level@_fan#. You need to set four temperatures 170for each fan. 171 172 173/sys files 174---------- 175 176pwm[1-7] 177 - this file stores PWM duty cycle or DC value (fan speed) in range: 178 179 0 (stop) to 255 (full) 180pwm[1-3]_enable 181 - this file controls mode of fan/temperature control: 182 183 * 0 Disabled 184 * 1 Manual mode 185 * 2 Smart Fan II 186 * 3 Thermal Cruise 187pwm[1-7]_mode 188 - Select PWM or DC mode 189 190 * 0 DC 191 * 1 PWM 192thermal_cruise[1-3] 193 - Selects the desired temperature for cruise (degC) 194tolerance[1-3] 195 - Value in degrees of Celsius (degC) for +- T 196sf2_point[1-4]_fan[1-3] 197 - four temperature points for each fan for Smart Fan II 198sf2_level[1-3]_fan[1-3] 199 - three PWM/DC levels for each fan for Smart Fan II