1 Kernel driver amc6821 2 ===================== 3 4 Supported 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 14 Authors: 15 Tomaz Mertelj <tomaz.mertelj@guest.arnes.si> 16 17 18 Description 19 ----------- 20 21 This driver implements support for the Texas Instruments amc6821 chip. 22 The chip has one on-chip and one remote temperature sensor and one pwm fan 23 regulator. 24 The pwm can be controlled either from software or automatically. 25 26 The driver provides the following sensor accesses in sysfs: 27 28 ======================= == =============================================== 29 temp1_input ro on-chip temperature 30 temp1_min rw " 31 temp1_max rw " 32 temp1_crit rw " 33 temp1_min_alarm ro " 34 temp1_max_alarm ro " 35 temp1_crit_alarm ro " 36 37 temp2_input ro remote temperature 38 temp2_min rw " 39 temp2_max rw " 40 temp2_crit rw " 41 temp2_min_alarm ro " 42 temp2_max_alarm ro " 43 temp2_crit_alarm ro " 44 temp2_fault ro " 45 46 fan1_input ro tachometer speed 47 fan1_min rw " 48 fan1_max rw " 49 fan1_fault ro " 50 fan1_pulses rw Pulses per revolution can be either 2 or 4. 51 fan1_target rw Target fan speed, to be used with pwm1_enable 52 mode 4. 53 54 pwm1 rw pwm1 55 pwm1_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. 61 pwm1_mode rw Fan duty control mode (0=DC, 1=PWM) 62 pwm1_auto_channels_temp ro 1 if pwm_enable==2, 3 if pwm_enable==3 63 pwm1_auto_point1_pwm ro Hardwired to 0, shared for both 64 temperature channels. 65 pwm1_auto_point2_pwm rw This value is shared for both temperature 66 channels. 67 pwm1_auto_point3_pwm rw Hardwired to 255, shared for both 68 temperature channels. 69 70 temp1_auto_point1_temp ro Hardwired to temp2_auto_point1_temp 71 which is rw. Below this temperature fan stops. 72 temp1_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. 78 temp1_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 85 temp2_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. 89 temp2_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 95 temp2_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 ======================= == =============================================== 101 102 103 Module parameters 104 ----------------- 105 106 If your board has a BIOS that initializes the amc6821 correctly, you should 107 load the module with: init=0. 108 109 If your board BIOS doesn't initialize the chip, or you want 110 different settings, you can set the following parameters: 111 112 - init=1, 113 - pwminv: 0 default pwm output, 1 inverts pwm output.
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.