0001 Kernel driver amc6821
0002 =====================
0003
0004 Supported chips:
0005
0006 Texas Instruments AMC6821
0007
0008 Prefix: 'amc6821'
0009
0010 Addresses scanned: 0x18, 0x19, 0x1a, 0x2c, 0x2d, 0x2e, 0x4c, 0x4d, 0x4e
0011
0012 Datasheet: http://focus.ti.com/docs/prod/folders/print/amc6821.html
0013
0014 Authors:
0015 Tomaz Mertelj <tomaz.mertelj@guest.arnes.si>
0016
0017
0018 Description
0019 -----------
0020
0021 This driver implements support for the Texas Instruments amc6821 chip.
0022 The chip has one on-chip and one remote temperature sensor and one pwm fan
0023 regulator.
0024 The pwm can be controlled either from software or automatically.
0025
0026 The driver provides the following sensor accesses in sysfs:
0027
0028 ======================= == ===============================================
0029 temp1_input ro on-chip temperature
0030 temp1_min rw "
0031 temp1_max rw "
0032 temp1_crit rw "
0033 temp1_min_alarm ro "
0034 temp1_max_alarm ro "
0035 temp1_crit_alarm ro "
0036
0037 temp2_input ro remote temperature
0038 temp2_min rw "
0039 temp2_max rw "
0040 temp2_crit rw "
0041 temp2_min_alarm ro "
0042 temp2_max_alarm ro "
0043 temp2_crit_alarm ro "
0044 temp2_fault ro "
0045
0046 fan1_input ro tachometer speed
0047 fan1_min rw "
0048 fan1_max rw "
0049 fan1_fault ro "
0050 fan1_div rw Fan divisor can be either 2 or 4.
0051
0052 pwm1 rw pwm1
0053 pwm1_enable rw regulator mode, 1=open loop, 2=fan controlled
0054 by remote temperature, 3=fan controlled by
0055 combination of the on-chip temperature and
0056 remote-sensor temperature,
0057 pwm1_auto_channels_temp ro 1 if pwm_enable==2, 3 if pwm_enable==3
0058 pwm1_auto_point1_pwm ro Hardwired to 0, shared for both
0059 temperature channels.
0060 pwm1_auto_point2_pwm rw This value is shared for both temperature
0061 channels.
0062 pwm1_auto_point3_pwm rw Hardwired to 255, shared for both
0063 temperature channels.
0064
0065 temp1_auto_point1_temp ro Hardwired to temp2_auto_point1_temp
0066 which is rw. Below this temperature fan stops.
0067 temp1_auto_point2_temp rw The low-temperature limit of the proportional
0068 range. Below this temperature
0069 pwm1 = pwm1_auto_point2_pwm. It can go from
0070 0 degree C to 124 degree C in steps of
0071 4 degree C. Read it out after writing to get
0072 the actual value.
0073 temp1_auto_point3_temp rw Above this temperature fan runs at maximum
0074 speed. It can go from temp1_auto_point2_temp.
0075 It can only have certain discrete values
0076 which depend on temp1_auto_point2_temp and
0077 pwm1_auto_point2_pwm. Read it out after
0078 writing to get the actual value.
0079
0080 temp2_auto_point1_temp rw Must be between 0 degree C and 63 degree C and
0081 it defines the passive cooling temperature.
0082 Below this temperature the fan stops in
0083 the closed loop mode.
0084 temp2_auto_point2_temp rw The low-temperature limit of the proportional
0085 range. Below this temperature
0086 pwm1 = pwm1_auto_point2_pwm. It can go from
0087 0 degree C to 124 degree C in steps
0088 of 4 degree C.
0089
0090 temp2_auto_point3_temp rw Above this temperature fan runs at maximum
0091 speed. It can only have certain discrete
0092 values which depend on temp2_auto_point2_temp
0093 and pwm1_auto_point2_pwm. Read it out after
0094 writing to get actual value.
0095 ======================= == ===============================================
0096
0097
0098 Module parameters
0099 -----------------
0100
0101 If your board has a BIOS that initializes the amc6821 correctly, you should
0102 load the module with: init=0.
0103
0104 If your board BIOS doesn't initialize the chip, or you want
0105 different settings, you can set the following parameters:
0106
0107 - init=1,
0108 - pwminv: 0 default pwm output, 1 inverts pwm output.
