1Kernel driver lm85 2================== 3 4Supported chips: 5 6 * National Semiconductor LM85 (B and C versions) 7 8 Prefix: 'lm85b' or 'lm85c' 9 10 Addresses scanned: I2C 0x2c, 0x2d, 0x2e 11 12 Datasheet: http://www.national.com/pf/LM/LM85.html 13 14 * Texas Instruments LM96000 15 16 Prefix: 'lm9600' 17 18 Addresses scanned: I2C 0x2c, 0x2d, 0x2e 19 20 Datasheet: http://www.ti.com/lit/ds/symlink/lm96000.pdf 21 22 * Analog Devices ADM1027 23 24 Prefix: 'adm1027' 25 26 Addresses scanned: I2C 0x2c, 0x2d, 0x2e 27 28 Datasheet: http://www.onsemi.com/PowerSolutions/product.do?id=ADM1027 29 30 * Analog Devices ADT7463 31 32 Prefix: 'adt7463' 33 34 Addresses scanned: I2C 0x2c, 0x2d, 0x2e 35 36 Datasheet: http://www.onsemi.com/PowerSolutions/product.do?id=ADT7463 37 38 * Analog Devices ADT7468 39 40 Prefix: 'adt7468' 41 42 Addresses scanned: I2C 0x2c, 0x2d, 0x2e 43 44 Datasheet: http://www.onsemi.com/PowerSolutions/product.do?id=ADT7468 45 46 * SMSC EMC6D100, SMSC EMC6D101 47 48 Prefix: 'emc6d100' 49 50 Addresses scanned: I2C 0x2c, 0x2d, 0x2e 51 52 Datasheet: http://www.smsc.com/media/Downloads_Public/discontinued/6d100.pdf 53 54 * SMSC EMC6D102 55 56 Prefix: 'emc6d102' 57 58 Addresses scanned: I2C 0x2c, 0x2d, 0x2e 59 60 Datasheet: http://www.smsc.com/main/catalog/emc6d102.html 61 62 * SMSC EMC6D103 63 64 Prefix: 'emc6d103' 65 66 Addresses scanned: I2C 0x2c, 0x2d, 0x2e 67 68 Datasheet: http://www.smsc.com/main/catalog/emc6d103.html 69 70 * SMSC EMC6D103S 71 72 Prefix: 'emc6d103s' 73 74 Addresses scanned: I2C 0x2c, 0x2d, 0x2e 75 76 Datasheet: http://www.smsc.com/main/catalog/emc6d103s.html 77 78Authors: 79 - Philip Pokorny <ppokorny@penguincomputing.com>, 80 - Frodo Looijaard <frodol@dds.nl>, 81 - Richard Barrington <rich_b_nz@clear.net.nz>, 82 - Margit Schubert-While <margitsw@t-online.de>, 83 - Justin Thiessen <jthiessen@penguincomputing.com> 84 85Description 86----------- 87 88This driver implements support for the National Semiconductor LM85 and 89compatible chips including the Analog Devices ADM1027, ADT7463, ADT7468 and 90SMSC EMC6D10x chips family. 91 92The LM85 uses the 2-wire interface compatible with the SMBUS 2.0 93specification. Using an analog to digital converter it measures three (3) 94temperatures and five (5) voltages. It has four (4) 16-bit counters for 95measuring fan speed. Five (5) digital inputs are provided for sampling the 96VID signals from the processor to the VRM. Lastly, there are three (3) PWM 97outputs that can be used to control fan speed. 98 99The voltage inputs have internal scaling resistors so that the following 100voltage can be measured without external resistors: 101 102 2.5V, 3.3V, 5V, 12V, and CPU core voltage (2.25V) 103 104The temperatures measured are one internal diode, and two remote diodes. 105Remote 1 is generally the CPU temperature. These inputs are designed to 106measure a thermal diode like the one in a Pentium 4 processor in a socket 107423 or socket 478 package. They can also measure temperature using a 108transistor like the 2N3904. 109 110A sophisticated control system for the PWM outputs is designed into the 111LM85 that allows fan speed to be adjusted automatically based on any of the 112three temperature sensors. Each PWM output is individually adjustable and 113programmable. Once configured, the LM85 will adjust the PWM outputs in 114response to the measured temperatures without further host intervention. 115This feature can also be disabled for manual control of the PWM's. 116 117Each of the measured inputs (voltage, temperature, fan speed) has 118corresponding high/low limit values. The LM85 will signal an ALARM if any 119measured value exceeds either limit. 120 121The LM85 samples all inputs continuously. The lm85 driver will not read 122the registers more often than once a second. Further, configuration data is 123only read once each 5 minutes. There is twice as much config data as 124measurements, so this would seem to be a worthwhile optimization. 125 126Special Features 127---------------- 128 129The LM85 has four fan speed monitoring modes. The ADM1027 has only two. 130Both have special circuitry to compensate for PWM interactions with the 131TACH signal from the fans. The ADM1027 can be configured to measure the 132speed of a two wire fan, but the input conditioning circuitry is different 133for 3-wire and 2-wire mode. For this reason, the 2-wire fan modes are not 134exposed to user control. The BIOS should initialize them to the correct 135mode. If you've designed your own ADM1027, you'll have to modify the 136init_client function and add an insmod parameter to set this up. 137 138To smooth the response of fans to changes in temperature, the LM85 has an 139optional filter for smoothing temperatures. The ADM1027 has the same 140config option but uses it to rate limit the changes to fan speed instead. 141 142The ADM1027, ADT7463 and ADT7468 have a 10-bit ADC and can therefore 143measure temperatures with 0.25 degC resolution. They also provide an offset 144to the temperature readings that is automatically applied during 145measurement. This offset can be used to zero out any errors due to traces 146and placement. The documentation says that the offset is in 0.25 degC 147steps, but in initial testing of the ADM1027 it was 1.00 degC steps. Analog 148Devices has confirmed this "bug". The ADT7463 is reported to work as 149described in the documentation. The current lm85 driver does not show the 150offset register. 151 152The ADT7468 has a high-frequency PWM mode, where all PWM outputs are 153driven by a 22.5 kHz clock. This is a global mode, not per-PWM output, 154which means that setting any PWM frequency above 11.3 kHz will switch 155all 3 PWM outputs to a 22.5 kHz frequency. Conversely, setting any PWM 156frequency below 11.3 kHz will switch all 3 PWM outputs to a frequency 157between 10 and 100 Hz, which can then be tuned separately. 158 159See the vendor datasheets for more information. There is application note 160from National (AN-1260) with some additional information about the LM85. 161The Analog Devices datasheet is very detailed and describes a procedure for 162determining an optimal configuration for the automatic PWM control. 163 164The SMSC EMC6D100 & EMC6D101 monitor external voltages, temperatures, and 165fan speeds. They use this monitoring capability to alert the system to out 166of limit conditions and can automatically control the speeds of multiple 167fans in a PC or embedded system. The EMC6D101, available in a 24-pin SSOP 168package, and the EMC6D100, available in a 28-pin SSOP package, are designed 169to be register compatible. The EMC6D100 offers all the features of the 170EMC6D101 plus additional voltage monitoring and system control features. 171Unfortunately it is not possible to distinguish between the package 172versions on register level so these additional voltage inputs may read 173zero. EMC6D102 and EMC6D103 feature additional ADC bits thus extending precision 174of voltage and temperature channels. 175 176SMSC EMC6D103S is similar to EMC6D103, but does not support pwm#_auto_pwm_minctl 177and temp#_auto_temp_off. 178 179The LM96000 supports additional high frequency PWM modes (22.5 kHz, 24 kHz, 18025.7 kHz, 27.7 kHz and 30 kHz), which can be configured on a per-PWM basis. 181 182Hardware Configurations 183----------------------- 184 185The LM85 can be jumpered for 3 different SMBus addresses. There are 186no other hardware configuration options for the LM85. 187 188The lm85 driver detects both LM85B and LM85C revisions of the chip. See the 189datasheet for a complete description of the differences. Other than 190identifying the chip, the driver behaves no differently with regard to 191these two chips. The LM85B is recommended for new designs. 192 193The ADM1027, ADT7463 and ADT7468 chips have an optional SMBALERT output 194that can be used to signal the chipset in case a limit is exceeded or the 195temperature sensors fail. Individual sensor interrupts can be masked so 196they won't trigger SMBALERT. The SMBALERT output if configured replaces one 197of the other functions (PWM2 or IN0). This functionality is not implemented 198in current driver. 199 200The ADT7463 and ADT7468 also have an optional THERM output/input which can 201be connected to the processor PROC_HOT output. If available, the autofan 202control dynamic Tmin feature can be enabled to keep the system temperature 203within spec (just?!) with the least possible fan noise. 204 205Configuration Notes 206------------------- 207 208Besides standard interfaces driver adds following: 209 210* Temperatures and Zones 211 212Each temperature sensor is associated with a Zone. There are three 213sensors and therefore three zones (# 1, 2 and 3). Each zone has the following 214temperature configuration points: 215 216* temp#_auto_temp_off 217 - temperature below which fans should be off or spinning very low. 218* temp#_auto_temp_min 219 - temperature over which fans start to spin. 220* temp#_auto_temp_max 221 - temperature when fans spin at full speed. 222* temp#_auto_temp_crit 223 - temperature when all fans will run full speed. 224 225PWM Control 226^^^^^^^^^^^ 227 228There are three PWM outputs. The LM85 datasheet suggests that the 229pwm3 output control both fan3 and fan4. Each PWM can be individually 230configured and assigned to a zone for its control value. Each PWM can be 231configured individually according to the following options. 232 233* pwm#_auto_pwm_min 234 - this specifies the PWM value for temp#_auto_temp_off 235 temperature. (PWM value from 0 to 255) 236 237* pwm#_auto_pwm_minctl 238 - this flags selects for temp#_auto_temp_off temperature 239 the behaviour of fans. Write 1 to let fans spinning at 240 pwm#_auto_pwm_min or write 0 to let them off. 241 242.. note:: 243 244 It has been reported that there is a bug in the LM85 that causes 245 the flag to be associated with the zones not the PWMs. This 246 contradicts all the published documentation. Setting pwm#_min_ctl 247 in this case actually affects all PWMs controlled by zone '#'. 248 249PWM Controlling Zone selection 250^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 251 252* pwm#_auto_channels 253 - controls zone that is associated with PWM 254 255Configuration choices: 256 257========== ============================================= 258Value Meaning 259========== ============================================= 260 1 Controlled by Zone 1 261 2 Controlled by Zone 2 262 3 Controlled by Zone 3 263 23 Controlled by higher temp of Zone 2 or 3 264 123 Controlled by highest temp of Zone 1, 2 or 3 265 0 PWM always 0% (off) 266 -1 PWM always 100% (full on) 267 -2 Manual control (write to 'pwm#' to set) 268========== ============================================= 269 270The National LM85's have two vendor specific configuration 271features. Tach. mode and Spinup Control. For more details on these, 272see the LM85 datasheet or Application Note AN-1260. These features 273are not currently supported by the lm85 driver. 274 275The Analog Devices ADM1027 has several vendor specific enhancements. 276The number of pulses-per-rev of the fans can be set, Tach monitoring 277can be optimized for PWM operation, and an offset can be applied to 278the temperatures to compensate for systemic errors in the 279measurements. These features are not currently supported by the lm85 280driver. 281 282In addition to the ADM1027 features, the ADT7463 and ADT7468 also have 283Tmin control and THERM asserted counts. Automatic Tmin control acts to 284adjust the Tmin value to maintain the measured temperature sensor at a 285specified temperature. There isn't much documentation on this feature in 286the ADT7463 data sheet. This is not supported by current driver. 287