Documentation/hwmon/f71805f

   1 Kernel driver f71805f
   2 =====================
   3
   4 Supported chips:
   5   * Fintek F71805F/FG
   6     Prefix: 'f71805f'
   7     Addresses scanned: none, address read from Super I/O config space
   8     Datasheet: Provided by Fintek on request
   9   * Fintek F71872F/FG
  10     Prefix: 'f71872f'
  11     Addresses scanned: none, address read from Super I/O config space
  12     Datasheet: Provided by Fintek on request
  13
  14 Author: Jean Delvare <khali@linux-fr.org>
  15
  16 Thanks to Denis Kieft from Barracuda Networks for the donation of a
  17 test system (custom Jetway K8M8MS motherboard, with CPU and RAM) and
  18 for providing initial documentation.
  19
  20 Thanks to Kris Chen and Aaron Huang from Fintek for answering technical
  21 questions and providing additional documentation.
  22
  23 Thanks to Chris Lin from Jetway for providing wiring schematics and
  24 answering technical questions.
  25
  26
  27 Description
  28 -----------
  29
  30 The Fintek F71805F/FG Super I/O chip includes complete hardware monitoring
  31 capabilities. It can monitor up to 9 voltages (counting its own power
  32 source), 3 fans and 3 temperature sensors.
  33
  34 This chip also has fan controlling features, using either DC or PWM, in
  35 three different modes (one manual, two automatic).
  36
  37 The Fintek F71872F/FG Super I/O chip is almost the same, with two
  38 additional internal voltages monitored (VSB and battery). It also features
  39 6 VID inputs. The VID inputs are not yet supported by this driver.
  40
  41 The driver assumes that no more than one chip is present, which seems
  42 reasonable.
  43
  44
  45 Voltage Monitoring
  46 ------------------
  47
  48 Voltages are sampled by an 8-bit ADC with a LSB of 8 mV. The supported
  49 range is thus from 0 to 2.040 V. Voltage values outside of this range
  50 need external resistors. An exception is in0, which is used to monitor
  51 the chip's own power source (+3.3V), and is divided internally by a
  52 factor 2. For the F71872F/FG, in9 (VSB) and in10 (battery) are also
  53 divided internally by a factor 2.
  54
  55 The two LSB of the voltage limit registers are not used (always 0), so
  56 you can only set the limits in steps of 32 mV (before scaling).
  57
  58 The wirings and resistor values suggested by Fintek are as follow:
  59
  60         pin                                           expected
  61         name    use           R1      R2     divider  raw val.
  62
  63 in0     VCC     VCC3.3V     int.    int.        2.00    1.65 V
  64 in1     VIN1    VTT1.2V      10K       -        1.00    1.20 V
  65 in2     VIN2    VRAM        100K    100K        2.00   ~1.25 V (1)
  66 in3     VIN3    VCHIPSET     47K    100K        1.47    2.24 V (2)
  67 in4     VIN4    VCC5V       200K     47K        5.25    0.95 V
  68 in5     VIN5    +12V        200K     20K       11.00    1.05 V
  69 in6     VIN6    VCC1.5V      10K       -        1.00    1.50 V
  70 in7     VIN7    VCORE        10K       -        1.00   ~1.40 V (1)
  71 in8     VIN8    VSB5V       200K     47K        1.00    0.95 V
  72 in10    VSB     VSB3.3V     int.    int.        2.00    1.65 V (3)
  73 in9     VBAT    VBATTERY    int.    int.        2.00    1.50 V (3)
  74
  75 (1) Depends on your hardware setup.
  76 (2) Obviously not correct, swapping R1 and R2 would make more sense.
  77 (3) F71872F/FG only.
  78
  79 These values can be used as hints at best, as motherboard manufacturers
  80 are free to use a completely different setup. As a matter of fact, the
  81 Jetway K8M8MS uses a significantly different setup. You will have to
  82 find out documentation about your own motherboard, and edit sensors.conf
  83 accordingly.
  84
  85 Each voltage measured has associated low and high limits, each of which
  86 triggers an alarm when crossed.
  87
  88
  89 Fan Monitoring
  90 --------------
  91
  92 Fan rotation speeds are reported as 12-bit values from a gated clock
  93 signal. Speeds down to 366 RPM can be measured. There is no theoretical
  94 high limit, but values over 6000 RPM seem to cause problem. The effective
  95 resolution is much lower than you would expect, the step between different
  96 register values being 10 rather than 1.
  97
  98 The chip assumes 2 pulse-per-revolution fans.
  99
 100 An alarm is triggered if the rotation speed drops below a programmable
 101 limit or is too low to be measured.
 102
 103
 104 Temperature Monitoring
 105 ----------------------
 106
 107 Temperatures are reported in degrees Celsius. Each temperature measured
 108 has a high limit, those crossing triggers an alarm. There is an associated
 109 hysteresis value, below which the temperature has to drop before the
 110 alarm is cleared.
 111
 112 All temperature channels are external, there is no embedded temperature
 113 sensor. Each channel can be used for connecting either a thermal diode
 114 or a thermistor. The driver reports the currently selected mode, but
 115 doesn't allow changing it. In theory, the BIOS should have configured
 116 everything properly.
 117
 118
 119 Fan Control
 120 -----------
 121
 122 Both PWM (pulse-width modulation) and DC fan speed control methods are
 123 supported. The right one to use depends on external circuitry on the
 124 motherboard, so the driver assumes that the BIOS set the method
 125 properly. The driver will report the method, but won't let you change
 126 it.
 127
 128 When the PWM method is used, you can select the operating frequency,
 129 from 187.5 kHz (default) to 31 Hz. The best frequency depends on the
 130 fan model. As a rule of thumb, lower frequencies seem to give better
 131 control, but may generate annoying high-pitch noise. Fintek recommends
 132 not going below 1 kHz, as the fan tachometers get confused by lower
 133 frequencies as well.
 134
 135 When the DC method is used, Fintek recommends not going below 5 V, which
 136 corresponds to a pwm value of 106 for the driver. The driver doesn't
 137 enforce this limit though.
 138
 139 Three different fan control modes are supported:
 140
 141 * Manual mode
 142   You ask for a specific PWM duty cycle or DC voltage.
 143
 144 * Fan speed mode
 145   You ask for a specific fan speed. This mode assumes that pwm1
 146   corresponds to fan1, pwm2 to fan2 and pwm3 to fan3.
 147
 148 * Temperature mode
 149   You define 3 temperature/fan speed trip points, and the fan speed is
 150   adjusted depending on the measured temperature, using interpolation.
 151   This mode is not yet supported by the driver.