Based on kernel version 2.6.33. Page generated on 2010-02-24 15:36 EST.
1 Kernel driver adt7473 2 ====================== 3 4 Supported chips: 5 * Analog Devices ADT7473 6 Prefix: 'adt7473' 7 Addresses scanned: I2C 0x2C, 0x2D, 0x2E 8 Datasheet: Publicly available at the Analog Devices website 9 10 Author: Darrick J. Wong 11 12 This driver is depreacted, please use the adt7475 driver instead. 13 14 Description 15 ----------- 16 17 This driver implements support for the Analog Devices ADT7473 chip family. 18 19 The ADT7473 uses the 2-wire interface compatible with the SMBUS 2.0 20 specification. Using an analog to digital converter it measures three (3) 21 temperatures and two (2) voltages. It has four (4) 16-bit counters for 22 measuring fan speed. There are three (3) PWM outputs that can be used 23 to control fan speed. 24 25 A sophisticated control system for the PWM outputs is designed into the 26 ADT7473 that allows fan speed to be adjusted automatically based on any of the 27 three temperature sensors. Each PWM output is individually adjustable and 28 programmable. Once configured, the ADT7473 will adjust the PWM outputs in 29 response to the measured temperatures without further host intervention. 30 This feature can also be disabled for manual control of the PWM's. 31 32 Each of the measured inputs (voltage, temperature, fan speed) has 33 corresponding high/low limit values. The ADT7473 will signal an ALARM if 34 any measured value exceeds either limit. 35 36 The ADT7473 samples all inputs continuously. The driver will not read 37 the registers more often than once every other second. Further, 38 configuration data is only read once per minute. 39 40 Special Features 41 ---------------- 42 43 The ADT7473 have a 10-bit ADC and can therefore measure temperatures 44 with 0.25 degC resolution. Temperature readings can be configured either 45 for twos complement format or "Offset 64" format, wherein 63 is subtracted 46 from the raw value to get the temperature value. 47 48 The Analog Devices datasheet is very detailed and describes a procedure for 49 determining an optimal configuration for the automatic PWM control. 50 51 Configuration Notes 52 ------------------- 53 54 Besides standard interfaces driver adds the following: 55 56 * PWM Control 57 58 * pwm#_auto_point1_pwm and temp#_auto_point1_temp and 59 * pwm#_auto_point2_pwm and temp#_auto_point2_temp - 60 61 point1: Set the pwm speed at a lower temperature bound. 62 point2: Set the pwm speed at a higher temperature bound. 63 64 The ADT7473 will scale the pwm between the lower and higher pwm speed when 65 the temperature is between the two temperature boundaries. PWM values range 66 from 0 (off) to 255 (full speed). Fan speed will be set to maximum when the 67 temperature sensor associated with the PWM control exceeds temp#_max. 68 69 Notes 70 ----- 71 72 The NVIDIA binary driver presents an ADT7473 chip via an on-card i2c bus. 73 Unfortunately, they fail to set the i2c adapter class, so this driver may 74 fail to find the chip until the nvidia driver is patched.