1Kernel driver amc6821 2===================== 3 4Supported chips: 5 6 Texas Instruments AMC6821 7 8 Prefix: 'amc6821' 9 10 Addresses scanned: 0x18, 0x19, 0x1a, 0x2c, 0x2d, 0x2e, 0x4c, 0x4d, 0x4e 11 12 Datasheet: http://focus.ti.com/docs/prod/folders/print/amc6821.html 13 14Authors: 15 Tomaz Mertelj <tomaz.mertelj@guest.arnes.si> 16 17 18Description 19----------- 20 21This driver implements support for the Texas Instruments amc6821 chip. 22The chip has one on-chip and one remote temperature sensor and one pwm fan 23regulator. 24The pwm can be controlled either from software or automatically. 25 26The driver provides the following sensor accesses in sysfs: 27 28======================= == =============================================== 29temp1_input ro on-chip temperature 30temp1_min rw " 31temp1_max rw " 32temp1_crit rw " 33temp1_min_alarm ro " 34temp1_max_alarm ro " 35temp1_crit_alarm ro " 36 37temp2_input ro remote temperature 38temp2_min rw " 39temp2_max rw " 40temp2_crit rw " 41temp2_min_alarm ro " 42temp2_max_alarm ro " 43temp2_crit_alarm ro " 44temp2_fault ro " 45 46fan1_input ro tachometer speed 47fan1_min rw " 48fan1_max rw " 49fan1_fault ro " 50fan1_pulses rw Pulses per revolution can be either 2 or 4. 51fan1_target rw Target fan speed, to be used with pwm1_enable 52 mode 4. 53 54pwm1 rw pwm1 55pwm1_enable rw regulator mode, 1=open loop, 2=fan controlled 56 by remote temperature, 3=fan controlled by 57 combination of the on-chip temperature and 58 remote-sensor temperature, 59 4=fan controlled by target rpm set with 60 fan1_target attribute. 61pwm1_mode rw Fan duty control mode (0=DC, 1=PWM) 62pwm1_auto_channels_temp ro 1 if pwm_enable==2, 3 if pwm_enable==3 63pwm1_auto_point1_pwm ro Hardwired to 0, shared for both 64 temperature channels. 65pwm1_auto_point2_pwm rw This value is shared for both temperature 66 channels. 67pwm1_auto_point3_pwm rw Hardwired to 255, shared for both 68 temperature channels. 69 70temp1_auto_point1_temp ro Hardwired to temp2_auto_point1_temp 71 which is rw. Below this temperature fan stops. 72temp1_auto_point2_temp rw The low-temperature limit of the proportional 73 range. Below this temperature 74 pwm1 = pwm1_auto_point2_pwm. It can go from 75 0 degree C to 124 degree C in steps of 76 4 degree C. Read it out after writing to get 77 the actual value. 78temp1_auto_point3_temp rw Above this temperature fan runs at maximum 79 speed. It can go from temp1_auto_point2_temp. 80 It can only have certain discrete values 81 which depend on temp1_auto_point2_temp and 82 pwm1_auto_point2_pwm. Read it out after 83 writing to get the actual value. 84 85temp2_auto_point1_temp rw Must be between 0 degree C and 63 degree C and 86 it defines the passive cooling temperature. 87 Below this temperature the fan stops in 88 the closed loop mode. 89temp2_auto_point2_temp rw The low-temperature limit of the proportional 90 range. Below this temperature 91 pwm1 = pwm1_auto_point2_pwm. It can go from 92 0 degree C to 124 degree C in steps 93 of 4 degree C. 94 95temp2_auto_point3_temp rw Above this temperature fan runs at maximum 96 speed. It can only have certain discrete 97 values which depend on temp2_auto_point2_temp 98 and pwm1_auto_point2_pwm. Read it out after 99 writing to get actual value. 100======================= == =============================================== 101 102 103Module parameters 104----------------- 105 106If your board has a BIOS that initializes the amc6821 correctly, you should 107load the module with: init=0. 108 109If your board BIOS doesn't initialize the chip, or you want 110different settings, you can set the following parameters: 111 112- init=1, 113- pwminv: 0 default pwm output, 1 inverts pwm output. 114