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Kernel driver max6650
Supported chips:
* Maxim MAX6650
Prefix: 'max6650'
Addresses scanned: none
* Maxim MAX6651
Prefix: 'max6651'
Addresses scanned: none
- Hans J. Koch <>
- John Morris <>
- Claus Gindhart <>
This driver implements support for the Maxim MAX6650 and MAX6651.
The 2 devices are very similar, but the MAX6550 has a reduced feature
set, 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_input ro fan tachometer speed in RPM
fan2_input ro "
fan3_input ro "
fan4_input ro "
fan1_target rw desired fan speed in RPM (closed loop mode only)
pwm1_enable rw regulator mode, 0=full on, 1=open loop, 2=closed loop
pwm1 rw relative speed (0-255), 255=max. speed.
Used in open loop mode only.
fan1_div rw sets the speed range the inputs can handle. Legal
values are 1, 2, 4, and 8. Use lower values for
faster fans.
=============== ======= =======================================================
Usage notes
This driver does not auto-detect devices. You will have to instantiate the
devices explicitly. Please see Documentation/i2c/instantiating-devices.rst for
Module parameters
If your board has a BIOS that initializes the MAX6650/6651 correctly, you can
simply load your module without parameters. It won't touch the configuration
registers then. If your board BIOS doesn't initialize the chip, or you want
different settings, you can set the following parameters:
voltage_12V: 5=5V fan, 12=12V fan, 0=don't change
prescaler: Possible values are 1,2,4,8,16, or 0 for don't change
clock: 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 fully
understand the meaning of these parameters before you attempt to change them.