Documentation/hwmon/smsc47m1

   1 Kernel driver smsc47m1
   2 ======================
   3
   4 Supported chips:
   5   * SMSC LPC47B27x, LPC47M112, LPC47M10x, LPC47M13x, LPC47M14x,
   6     LPC47M15x and LPC47M192
   7     Addresses scanned: none, address read from Super I/O config space
   8     Prefix: 'smsc47m1'
   9     Datasheets:
  10         http://www.smsc.com/media/Downloads_Public/Data_Sheets/47b272.pdf
  11         http://www.smsc.com/media/Downloads_Public/Data_Sheets/47m10x.pdf
  12         http://www.smsc.com/media/Downloads_Public/Data_Sheets/47m112.pdf
  13         http://www.smsc.com/
  14   * SMSC LPC47M292
  15     Addresses scanned: none, address read from Super I/O config space
  16     Prefix: 'smsc47m2'
  17     Datasheet: Not public
  18   * SMSC LPC47M997
  19     Addresses scanned: none, address read from Super I/O config space
  20     Prefix: 'smsc47m1'
  21     Datasheet: none
  22
  23 Authors:
  24         Mark D. Studebaker <mdsxyz123@yahoo.com>,
  25         With assistance from Bruce Allen <ballen@uwm.edu>, and his
  26         fan.c program: http://www.lsc-group.phys.uwm.edu/%7Eballen/driver/
  27         Gabriele Gorla <gorlik@yahoo.com>,
  28         Jean Delvare <jdelvare@suse.de>
  29
  30 Description
  31 -----------
  32
  33 The Standard Microsystems Corporation (SMSC) 47M1xx Super I/O chips
  34 contain monitoring and PWM control circuitry for two fans.
  35
  36 The LPC47M15x, LPC47M192 and LPC47M292 chips contain a full 'hardware
  37 monitoring block' in addition to the fan monitoring and control. The
  38 hardware monitoring block is not supported by this driver, use the
  39 smsc47m192 driver for that.
  40
  41 No documentation is available for the 47M997, but it has the same device
  42 ID as the 47M15x and 47M192 chips and seems to be compatible.
  43
  44 Fan rotation speeds are reported in RPM (rotations per minute). An alarm is
  45 triggered if the rotation speed has dropped below a programmable limit. Fan
  46 readings can be divided by a programmable divider (1, 2, 4 or 8) to give
  47 the readings more range or accuracy. Not all RPM values can accurately be
  48 represented, so some rounding is done. With a divider of 2, the lowest
  49 representable value is around 2600 RPM.
  50
  51 PWM values are from 0 to 255.
  52
  53 If an alarm triggers, it will remain triggered until the hardware register
  54 is read at least once. This means that the cause for the alarm may
  55 already have disappeared! Note that in the current implementation, all
  56 hardware registers are read whenever any data is read (unless it is less
  57 than 1.5 seconds since the last update). This means that you can easily
  58 miss once-only alarms.
  59
  60
  61 **********************
  62 The lm_sensors project gratefully acknowledges the support of
  63 Intel in the development of this driver.