Kernel driver amc6821
=====================
Supported chips:
Texas Instruments AMC6821
Prefix: 'amc6821'
Addresses scanned: 0x18, 0x19, 0x1a, 0x2c, 0x2d, 0x2e, 0x4c, 0x4d, 0x4e
Datasheet:
http://focus.ti.com/docs/prod/folders/print/amc6821.html
Authors:
Tomaz Mertelj <tomaz.mertelj@guest.arnes.si>
Description
-----------
This driver implements support for the Texas Instruments amc6821 chip.
The chip has one on-chip and one remote temperature sensor and one pwm fan
regulator.
The pwm can be controlled either from software or automatically.
The driver provides the following sensor accesses in sysfs:
======================= == ===============================================
temp1_input ro on-chip temperature
temp1_min rw "
temp1_max rw "
temp1_crit rw "
temp1_min_alarm ro "
temp1_max_alarm ro "
temp1_crit_alarm ro "
temp2_input ro remote temperature
temp2_min rw "
temp2_max rw "
temp2_crit rw "
temp2_min_alarm ro "
temp2_max_alarm ro "
temp2_crit_alarm ro "
temp2_fault ro "
fan1_input ro tachometer speed
fan1_min rw "
fan1_max rw "
fan1_fault ro "
fan1_pulses rw Pulses per revolution can be either 2 or 4.
fan1_target rw Target fan speed, to be used with pwm1_enable
mode 4.
pwm1 rw pwm1
pwm1_enable rw regulator mode, 1=open loop, 2=fan controlled
by remote temperature, 3=fan controlled by
combination of the on-chip temperature and
remote-sensor temperature,
4=fan controlled by target rpm set with
fan1_target attribute.
pwm1_mode rw Fan duty control mode (0=DC, 1=PWM)
pwm1_auto_channels_temp ro 1 if pwm_enable==2, 3 if pwm_enable==3
pwm1_auto_point1_pwm ro Hardwired to 0, shared for both
temperature channels.
pwm1_auto_point2_pwm rw This value is shared for both temperature
channels.
pwm1_auto_point3_pwm rw Hardwired to 255, shared for both
temperature channels.
temp1_auto_point1_temp ro Hardwired to temp2_auto_point1_temp
which is rw. Below this temperature fan stops.
temp1_auto_point2_temp rw The low-temperature limit of the proportional
range. Below this temperature
pwm1 = pwm1_auto_point2_pwm. It can go from
0 degree C to 124 degree C in steps of
4 degree C. Read it out after writing to get
the actual value.
temp1_auto_point3_temp rw Above this temperature fan runs at maximum
speed. It can go from temp1_auto_point2_temp.
It can only have certain discrete values
which depend on temp1_auto_point2_temp and
pwm1_auto_point2_pwm. Read it out after
writing to get the actual value.
temp2_auto_point1_temp rw Must be between 0 degree C and 63 degree C and
it defines the passive cooling temperature.
Below this temperature the fan stops in
the closed loop mode.
temp2_auto_point2_temp rw The low-temperature limit of the proportional
range. Below this temperature
pwm1 = pwm1_auto_point2_pwm. It can go from
0 degree C to 124 degree C in steps
of 4 degree C.
temp2_auto_point3_temp rw Above this temperature fan runs at maximum
speed. It can only have certain discrete
values which depend on temp2_auto_point2_temp
and pwm1_auto_point2_pwm. Read it out after
writing to get actual value.
======================= == ===============================================
Module parameters
-----------------
If your board has a BIOS that initializes the amc6821 correctly, you should
load the module with: init=0.
If your board BIOS doesn't initialize the chip, or you want
different settings, you can set the following parameters:
- init=1,
- pwminv: 0 default pwm output, 1 inverts pwm output.
