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 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_div rw Fan divisor can be either 2 or 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, 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.