1*4882a593SmuzhiyunKernel driver ds620 2*4882a593Smuzhiyun=================== 3*4882a593Smuzhiyun 4*4882a593SmuzhiyunSupported chips: 5*4882a593Smuzhiyun 6*4882a593Smuzhiyun * Dallas Semiconductor DS620 7*4882a593Smuzhiyun 8*4882a593Smuzhiyun Prefix: 'ds620' 9*4882a593Smuzhiyun 10*4882a593Smuzhiyun Datasheet: Publicly available at the Dallas Semiconductor website 11*4882a593Smuzhiyun 12*4882a593Smuzhiyun http://www.dalsemi.com/ 13*4882a593Smuzhiyun 14*4882a593SmuzhiyunAuthors: 15*4882a593Smuzhiyun Roland Stigge <stigge@antcom.de> 16*4882a593Smuzhiyun based on ds1621.c by 17*4882a593Smuzhiyun Christian W. Zuckschwerdt <zany@triq.net> 18*4882a593Smuzhiyun 19*4882a593SmuzhiyunDescription 20*4882a593Smuzhiyun----------- 21*4882a593Smuzhiyun 22*4882a593SmuzhiyunThe DS620 is a (one instance) digital thermometer and thermostat. It has both 23*4882a593Smuzhiyunhigh and low temperature limits which can be user defined (i.e. programmed 24*4882a593Smuzhiyuninto non-volatile on-chip registers). Temperature range is -55 degree Celsius 25*4882a593Smuzhiyunto +125. Between 0 and 70 degree Celsius, accuracy is 0.5 Kelvin. The value 26*4882a593Smuzhiyunreturned via sysfs displays post decimal positions. 27*4882a593Smuzhiyun 28*4882a593SmuzhiyunThe thermostat function works as follows: When configured via platform_data 29*4882a593Smuzhiyun(struct ds620_platform_data) .pomode == 0 (default), the thermostat output pin 30*4882a593SmuzhiyunPO is always low. If .pomode == 1, the thermostat is in PO_LOW mode. I.e., the 31*4882a593Smuzhiyunoutput pin PO becomes active when the temperature falls below temp1_min and 32*4882a593Smuzhiyunstays active until the temperature goes above temp1_max. 33*4882a593Smuzhiyun 34*4882a593SmuzhiyunLikewise, with .pomode == 2, the thermostat is in PO_HIGH mode. I.e., the PO 35*4882a593Smuzhiyunoutput pin becomes active when the temperature goes above temp1_max and stays 36*4882a593Smuzhiyunactive until the temperature falls below temp1_min. 37*4882a593Smuzhiyun 38*4882a593SmuzhiyunThe PO output pin of the DS620 operates active-low. 39