1*4882a593SmuzhiyunKernel driver lm87 2*4882a593Smuzhiyun================== 3*4882a593Smuzhiyun 4*4882a593SmuzhiyunSupported chips: 5*4882a593Smuzhiyun 6*4882a593Smuzhiyun * National Semiconductor LM87 7*4882a593Smuzhiyun 8*4882a593Smuzhiyun Prefix: 'lm87' 9*4882a593Smuzhiyun 10*4882a593Smuzhiyun Addresses scanned: I2C 0x2c - 0x2e 11*4882a593Smuzhiyun 12*4882a593Smuzhiyun Datasheet: http://www.national.com/pf/LM/LM87.html 13*4882a593Smuzhiyun 14*4882a593Smuzhiyun * Analog Devices ADM1024 15*4882a593Smuzhiyun 16*4882a593Smuzhiyun Prefix: 'adm1024' 17*4882a593Smuzhiyun 18*4882a593Smuzhiyun Addresses scanned: I2C 0x2c - 0x2e 19*4882a593Smuzhiyun 20*4882a593Smuzhiyun Datasheet: https://www.analog.com/en/prod/0,2877,ADM1024,00.html 21*4882a593Smuzhiyun 22*4882a593Smuzhiyun 23*4882a593SmuzhiyunAuthors: 24*4882a593Smuzhiyun - Frodo Looijaard <frodol@dds.nl>, 25*4882a593Smuzhiyun - Philip Edelbrock <phil@netroedge.com>, 26*4882a593Smuzhiyun - Mark Studebaker <mdsxyz123@yahoo.com>, 27*4882a593Smuzhiyun - Stephen Rousset <stephen.rousset@rocketlogix.com>, 28*4882a593Smuzhiyun - Dan Eaton <dan.eaton@rocketlogix.com>, 29*4882a593Smuzhiyun - Jean Delvare <jdelvare@suse.de>, 30*4882a593Smuzhiyun - Original 2.6 port Jeff Oliver 31*4882a593Smuzhiyun 32*4882a593SmuzhiyunDescription 33*4882a593Smuzhiyun----------- 34*4882a593Smuzhiyun 35*4882a593SmuzhiyunThis driver implements support for the National Semiconductor LM87 36*4882a593Smuzhiyunand the Analog Devices ADM1024. 37*4882a593Smuzhiyun 38*4882a593SmuzhiyunThe LM87 implements up to three temperature sensors, up to two fan 39*4882a593Smuzhiyunrotation speed sensors, up to seven voltage sensors, alarms, and some 40*4882a593Smuzhiyunmiscellaneous stuff. The ADM1024 is fully compatible. 41*4882a593Smuzhiyun 42*4882a593SmuzhiyunTemperatures are measured in degrees Celsius. Each input has a high 43*4882a593Smuzhiyunand low alarm settings. A high limit produces an alarm when the value 44*4882a593Smuzhiyungoes above it, and an alarm is also produced when the value goes below 45*4882a593Smuzhiyunthe low limit. 46*4882a593Smuzhiyun 47*4882a593SmuzhiyunFan rotation speeds are reported in RPM (rotations per minute). An alarm is 48*4882a593Smuzhiyuntriggered if the rotation speed has dropped below a programmable limit. Fan 49*4882a593Smuzhiyunreadings can be divided by a programmable divider (1, 2, 4 or 8) to give 50*4882a593Smuzhiyunthe readings more range or accuracy. Not all RPM values can accurately be 51*4882a593Smuzhiyunrepresented, so some rounding is done. With a divider of 2, the lowest 52*4882a593Smuzhiyunrepresentable value is around 2600 RPM. 53*4882a593Smuzhiyun 54*4882a593SmuzhiyunVoltage sensors (also known as IN sensors) report their values in 55*4882a593Smuzhiyunvolts. An alarm is triggered if the voltage has crossed a programmable 56*4882a593Smuzhiyunminimum or maximum limit. Note that minimum in this case always means 57*4882a593Smuzhiyun'closest to zero'; this is important for negative voltage measurements. 58*4882a593Smuzhiyun 59*4882a593SmuzhiyunIf an alarm triggers, it will remain triggered until the hardware register 60*4882a593Smuzhiyunis read at least once. This means that the cause for the alarm may 61*4882a593Smuzhiyunalready have disappeared! Note that in the current implementation, all 62*4882a593Smuzhiyunhardware registers are read whenever any data is read (unless it is less 63*4882a593Smuzhiyunthan 1.0 seconds since the last update). This means that you can easily 64*4882a593Smuzhiyunmiss once-only alarms. 65*4882a593Smuzhiyun 66*4882a593SmuzhiyunThe lm87 driver only updates its values each 1.0 seconds; reading it more 67*4882a593Smuzhiyunoften will do no harm, but will return 'old' values. 68*4882a593Smuzhiyun 69*4882a593Smuzhiyun 70*4882a593SmuzhiyunHardware Configurations 71*4882a593Smuzhiyun----------------------- 72*4882a593Smuzhiyun 73*4882a593SmuzhiyunThe LM87 has four pins which can serve one of two possible functions, 74*4882a593Smuzhiyundepending on the hardware configuration. 75*4882a593Smuzhiyun 76*4882a593SmuzhiyunSome functions share pins, so not all functions are available at the same 77*4882a593Smuzhiyuntime. Which are depends on the hardware setup. This driver normally 78*4882a593Smuzhiyunassumes that firmware configured the chip correctly. Where this is not 79*4882a593Smuzhiyunthe case, platform code must set the I2C client's platform_data to point 80*4882a593Smuzhiyunto a u8 value to be written to the channel register. 81*4882a593Smuzhiyun 82*4882a593SmuzhiyunFor reference, here is the list of exclusive functions: 83*4882a593Smuzhiyun - in0+in5 (default) or temp3 84*4882a593Smuzhiyun - fan1 (default) or in6 85*4882a593Smuzhiyun - fan2 (default) or in7 86*4882a593Smuzhiyun - VID lines (default) or IRQ lines (not handled by this driver) 87