1Kernel driver amc6821 2===================== 3 4Supported chips: 5 Texas Instruments AMC6821 6 Prefix: 'amc6821' 7 Addresses scanned: 0x18, 0x19, 0x1a, 0x2c, 0x2d, 0x2e, 0x4c, 0x4d, 0x4e 8 Datasheet: http://focus.ti.com/docs/prod/folders/print/amc6821.html 9 10Authors: 11 Tomaz Mertelj <tomaz.mertelj@guest.arnes.si> 12 13 14Description 15----------- 16 17This driver implements support for the Texas Instruments amc6821 chip. 18The chip has one on-chip and one remote temperature sensor and one pwm fan 19regulator. 20The pwm can be controlled either from software or automatically. 21 22The driver provides the following sensor accesses in sysfs: 23 24temp1_input ro on-chip temperature 25temp1_min rw " 26temp1_max rw " 27temp1_crit rw " 28temp1_min_alarm ro " 29temp1_max_alarm ro " 30temp1_crit_alarm ro " 31 32temp2_input ro remote temperature 33temp2_min rw " 34temp2_max rw " 35temp2_crit rw " 36temp2_min_alarm ro " 37temp2_max_alarm ro " 38temp2_crit_alarm ro " 39temp2_fault ro " 40 41fan1_input ro tachometer speed 42fan1_min rw " 43fan1_max rw " 44fan1_fault ro " 45fan1_div rw Fan divisor can be either 2 or 4. 46 47pwm1 rw pwm1 48pwm1_enable rw regulator mode, 1=open loop, 2=fan controlled 49 by remote temperature, 3=fan controlled by 50 combination of the on-chip temperature and 51 remote-sensor temperature, 52pwm1_auto_channels_temp ro 1 if pwm_enable==2, 3 if pwm_enable==3 53pwm1_auto_point1_pwm ro Hardwired to 0, shared for both 54 temperature channels. 55pwm1_auto_point2_pwm rw This value is shared for both temperature 56 channels. 57pwm1_auto_point3_pwm rw Hardwired to 255, shared for both 58 temperature channels. 59 60temp1_auto_point1_temp ro Hardwired to temp2_auto_point1_temp 61 which is rw. Below this temperature fan stops. 62temp1_auto_point2_temp rw The low-temperature limit of the proportional 63 range. Below this temperature 64 pwm1 = pwm1_auto_point2_pwm. It can go from 65 0 degree C to 124 degree C in steps of 66 4 degree C. Read it out after writing to get 67 the actual value. 68temp1_auto_point3_temp rw Above this temperature fan runs at maximum 69 speed. It can go from temp1_auto_point2_temp. 70 It can only have certain discrete values 71 which depend on temp1_auto_point2_temp and 72 pwm1_auto_point2_pwm. Read it out after 73 writing to get the actual value. 74 75temp2_auto_point1_temp rw Must be between 0 degree C and 63 degree C and 76 it defines the passive cooling temperature. 77 Below this temperature the fan stops in 78 the closed loop mode. 79temp2_auto_point2_temp rw The low-temperature limit of the proportional 80 range. Below this temperature 81 pwm1 = pwm1_auto_point2_pwm. It can go from 82 0 degree C to 124 degree C in steps 83 of 4 degree C. 84 85temp2_auto_point3_temp rw Above this temperature fan runs at maximum 86 speed. It can only have certain discrete 87 values which depend on temp2_auto_point2_temp 88 and pwm1_auto_point2_pwm. Read it out after 89 writing to get actual value. 90 91 92Module parameters 93----------------- 94 95If your board has a BIOS that initializes the amc6821 correctly, you should 96load the module with: init=0. 97 98If your board BIOS doesn't initialize the chip, or you want 99different settings, you can set the following parameters: 100init=1, 101pwminv: 0 default pwm output, 1 inverts pwm output. 102 103