1Kernel driver w83792d 2===================== 3 4Supported chips: 5 * Winbond W83792D 6 Prefix: 'w83792d' 7 Addresses scanned: I2C 0x2c - 0x2f 8 Datasheet: http://www.winbond.com.tw 9 10Author: Chunhao Huang 11Contact: DZShen <DZShen@Winbond.com.tw> 12 13 14Module Parameters 15----------------- 16 17* init int 18 (default 1) 19 Use 'init=0' to bypass initializing the chip. 20 Try this if your computer crashes when you load the module. 21 22* force_subclients=bus,caddr,saddr,saddr 23 This is used to force the i2c addresses for subclients of 24 a certain chip. Example usage is `force_subclients=0,0x2f,0x4a,0x4b' 25 to force the subclients of chip 0x2f on bus 0 to i2c addresses 26 0x4a and 0x4b. 27 28 29Description 30----------- 31 32This driver implements support for the Winbond W83792AD/D. 33 34Detection of the chip can sometimes be foiled because it can be in an 35internal state that allows no clean access (Bank with ID register is not 36currently selected). If you know the address of the chip, use a 'force' 37parameter; this will put it into a more well-behaved state first. 38 39The driver implements three temperature sensors, seven fan rotation speed 40sensors, nine voltage sensors, and two automatic fan regulation 41strategies called: Smart Fan I (Thermal Cruise mode) and Smart Fan II. 42Automatic fan control mode is possible only for fan1-fan3. Fan4-fan7 can run 43synchronized with selected fan (fan1-fan3). This functionality and manual PWM 44control for fan4-fan7 is not yet implemented. 45 46Temperatures are measured in degrees Celsius and measurement resolution is 1 47degC for temp1 and 0.5 degC for temp2 and temp3. An alarm is triggered when 48the temperature gets higher than the Overtemperature Shutdown value; it stays 49on until the temperature falls below the Hysteresis value. 50 51Fan rotation speeds are reported in RPM (rotations per minute). An alarm is 52triggered if the rotation speed has dropped below a programmable limit. Fan 53readings can be divided by a programmable divider (1, 2, 4, 8, 16, 32, 64 or 54128) to give the readings more range or accuracy. 55 56Voltage sensors (also known as IN sensors) report their values in millivolts. 57An alarm is triggered if the voltage has crossed a programmable minimum 58or maximum limit. 59 60Alarms are provided as output from "realtime status register". Following bits 61are defined: 62 63bit - alarm on: 640 - in0 651 - in1 662 - temp1 673 - temp2 684 - temp3 695 - fan1 706 - fan2 717 - fan3 728 - in2 739 - in3 7410 - in4 7511 - in5 7612 - in6 7713 - VID change 7814 - chassis 7915 - fan7 8016 - tart1 8117 - tart2 8218 - tart3 8319 - in7 8420 - in8 8521 - fan4 8622 - fan5 8723 - fan6 88 89Tart will be asserted while target temperature cannot be achieved after 3 minutes 90of full speed rotation of corresponding fan. 91 92In addition to the alarms described above, there is a CHAS alarm on the chips 93which triggers if your computer case is open (This one is latched, contrary 94to realtime alarms). 95 96The chips only update values each 3 seconds; reading them more often will 97do no harm, but will return 'old' values. 98 99 100W83792D PROBLEMS 101---------------- 102Known problems: 103 - This driver is only for Winbond W83792D C version device, there 104 are also some motherboards with B version W83792D device. The 105 calculation method to in6-in7(measured value, limits) is a little 106 different between C and B version. C or B version can be identified 107 by CR[0x49h]. 108 - The function of vid and vrm has not been finished, because I'm NOT 109 very familiar with them. Adding support is welcome. 110�� - The function of chassis open detection needs more tests. 111 - If you have ASUS server board and chip was not found: Then you will 112 need to upgrade to latest (or beta) BIOS. If it does not help please 113 contact us. 114 115Fan control 116----------- 117 118Manual mode 119----------- 120 121Works as expected. You just need to specify desired PWM/DC value (fan speed) 122in appropriate pwm# file. 123 124Thermal cruise 125-------------- 126 127In this mode, W83792D provides the Smart Fan system to automatically control 128fan speed to keep the temperatures of CPU and the system within specific 129range. At first a wanted temperature and interval must be set. This is done 130via thermal_cruise# file. The tolerance# file serves to create T +- tolerance 131interval. The fan speed will be lowered as long as the current temperature 132remains below the thermal_cruise# +- tolerance# value. Once the temperature 133exceeds the high limit (T+tolerance), the fan will be turned on with a 134specific speed set by pwm# and automatically controlled its PWM duty cycle 135with the temperature varying. Three conditions may occur: 136 137(1) If the temperature still exceeds the high limit, PWM duty 138cycle will increase slowly. 139 140(2) If the temperature goes below the high limit, but still above the low 141limit (T-tolerance), the fan speed will be fixed at the current speed because 142the temperature is in the target range. 143 144(3) If the temperature goes below the low limit, PWM duty cycle will decrease 145slowly to 0 or a preset stop value until the temperature exceeds the low 146limit. (The preset stop value handling is not yet implemented in driver) 147 148Smart Fan II 149------------ 150 151W83792D also provides a special mode for fan. Four temperature points are 152available. When related temperature sensors detects the temperature in preset 153temperature region (sf2_point@_fan# +- tolerance#) it will cause fans to run 154on programmed value from sf2_level@_fan#. You need to set four temperatures 155for each fan. 156 157 158/sys files 159---------- 160 161pwm[1-3] - this file stores PWM duty cycle or DC value (fan speed) in range: 162 0 (stop) to 255 (full) 163pwm[1-3]_enable - this file controls mode of fan/temperature control: 164 * 0 Disabled 165 * 1 Manual mode 166 * 2 Smart Fan II 167 * 3 Thermal Cruise 168pwm[1-3]_mode - Select PWM of DC mode 169 * 0 DC 170 * 1 PWM 171thermal_cruise[1-3] - Selects the desired temperature for cruise (degC) 172tolerance[1-3] - Value in degrees of Celsius (degC) for +- T 173sf2_point[1-4]_fan[1-3] - four temperature points for each fan for Smart Fan II 174sf2_level[1-3]_fan[1-3] - three PWM/DC levels for each fan for Smart Fan II 175