Kernel driver max6650

Supported chips:

Authors:

Description

This driver implements support for the Maxim MAX6650 and MAX6651.

The 2 devices are very similar, but the MAX6550 has a reduced featureset, e.g. only one fan-input, instead of 4 for the MAX6651.

The driver is not able to distinguish between the 2 devices.

The driver provides the following sensor accesses in sysfs:

fan1_inputrofan tachometer speed in RPM
fan2_inputro“
fan3_inputro“
fan4_inputro“
fan1_targetrwdesired fan speed in RPM (closed loop mode only)
pwm1_enablerwregulator mode, 0=full on, 1=open loop, 2=closed loop3=off
pwm1rwrelative speed (0-255), 255=max. speed.Used in open loop mode only.
fan1_divrwsets the speed range the inputs can handle. Legalvalues are 1, 2, 4, and 8. Use lower values forfaster fans.

Usage notes

This driver does not auto-detect devices. You will have to instantiate thedevices explicitly. Please see Documentation/i2c/instantiating-devices.rst fordetails.

Module parameters

If your board has a BIOS that initializes the MAX6650/6651 correctly, you cansimply load your module without parameters. It won’t touch the configurationregisters then. If your board BIOS doesn’t initialize the chip, or you wantdifferent settings, you can set the following parameters:

voltage_12V: 5=5V fan, 12=12V fan, 0=don’t changeprescaler: Possible values are 1,2,4,8,16, or 0 for don’t changeclock: The clock frequency in Hz of the chip the driver should assume [254000]

Please have a look at the MAX6650/6651 data sheet and make sure that you fullyunderstand the meaning of these parameters before you attempt to change them.