1*4882a593SmuzhiyunKernel driver max6650 2*4882a593Smuzhiyun===================== 3*4882a593Smuzhiyun 4*4882a593SmuzhiyunSupported chips: 5*4882a593Smuzhiyun 6*4882a593Smuzhiyun * Maxim MAX6650 7*4882a593Smuzhiyun 8*4882a593Smuzhiyun Prefix: 'max6650' 9*4882a593Smuzhiyun 10*4882a593Smuzhiyun Addresses scanned: none 11*4882a593Smuzhiyun 12*4882a593Smuzhiyun Datasheet: http://pdfserv.maxim-ic.com/en/ds/MAX6650-MAX6651.pdf 13*4882a593Smuzhiyun 14*4882a593Smuzhiyun * Maxim MAX6651 15*4882a593Smuzhiyun 16*4882a593Smuzhiyun Prefix: 'max6651' 17*4882a593Smuzhiyun 18*4882a593Smuzhiyun Addresses scanned: none 19*4882a593Smuzhiyun 20*4882a593Smuzhiyun Datasheet: http://pdfserv.maxim-ic.com/en/ds/MAX6650-MAX6651.pdf 21*4882a593Smuzhiyun 22*4882a593SmuzhiyunAuthors: 23*4882a593Smuzhiyun - Hans J. Koch <hjk@hansjkoch.de> 24*4882a593Smuzhiyun - John Morris <john.morris@spirentcom.com> 25*4882a593Smuzhiyun - Claus Gindhart <claus.gindhart@kontron.com> 26*4882a593Smuzhiyun 27*4882a593SmuzhiyunDescription 28*4882a593Smuzhiyun----------- 29*4882a593Smuzhiyun 30*4882a593SmuzhiyunThis driver implements support for the Maxim MAX6650 and MAX6651. 31*4882a593Smuzhiyun 32*4882a593SmuzhiyunThe 2 devices are very similar, but the MAX6550 has a reduced feature 33*4882a593Smuzhiyunset, e.g. only one fan-input, instead of 4 for the MAX6651. 34*4882a593Smuzhiyun 35*4882a593SmuzhiyunThe driver is not able to distinguish between the 2 devices. 36*4882a593Smuzhiyun 37*4882a593SmuzhiyunThe driver provides the following sensor accesses in sysfs: 38*4882a593Smuzhiyun 39*4882a593Smuzhiyun=============== ======= ======================================================= 40*4882a593Smuzhiyunfan1_input ro fan tachometer speed in RPM 41*4882a593Smuzhiyunfan2_input ro " 42*4882a593Smuzhiyunfan3_input ro " 43*4882a593Smuzhiyunfan4_input ro " 44*4882a593Smuzhiyunfan1_target rw desired fan speed in RPM (closed loop mode only) 45*4882a593Smuzhiyunpwm1_enable rw regulator mode, 0=full on, 1=open loop, 2=closed loop 46*4882a593Smuzhiyun 3=off 47*4882a593Smuzhiyunpwm1 rw relative speed (0-255), 255=max. speed. 48*4882a593Smuzhiyun Used in open loop mode only. 49*4882a593Smuzhiyunfan1_div rw sets the speed range the inputs can handle. Legal 50*4882a593Smuzhiyun values are 1, 2, 4, and 8. Use lower values for 51*4882a593Smuzhiyun faster fans. 52*4882a593Smuzhiyun=============== ======= ======================================================= 53*4882a593Smuzhiyun 54*4882a593SmuzhiyunUsage notes 55*4882a593Smuzhiyun----------- 56*4882a593Smuzhiyun 57*4882a593SmuzhiyunThis driver does not auto-detect devices. You will have to instantiate the 58*4882a593Smuzhiyundevices explicitly. Please see Documentation/i2c/instantiating-devices.rst for 59*4882a593Smuzhiyundetails. 60*4882a593Smuzhiyun 61*4882a593SmuzhiyunModule parameters 62*4882a593Smuzhiyun----------------- 63*4882a593Smuzhiyun 64*4882a593SmuzhiyunIf your board has a BIOS that initializes the MAX6650/6651 correctly, you can 65*4882a593Smuzhiyunsimply load your module without parameters. It won't touch the configuration 66*4882a593Smuzhiyunregisters then. If your board BIOS doesn't initialize the chip, or you want 67*4882a593Smuzhiyundifferent settings, you can set the following parameters: 68*4882a593Smuzhiyun 69*4882a593Smuzhiyunvoltage_12V: 5=5V fan, 12=12V fan, 0=don't change 70*4882a593Smuzhiyunprescaler: Possible values are 1,2,4,8,16, or 0 for don't change 71*4882a593Smuzhiyunclock: The clock frequency in Hz of the chip the driver should assume [254000] 72*4882a593Smuzhiyun 73*4882a593SmuzhiyunPlease have a look at the MAX6650/6651 data sheet and make sure that you fully 74*4882a593Smuzhiyununderstand the meaning of these parameters before you attempt to change them. 75