linux-stable/Documentation/devicetree/bindings/hwmon/max6650.txt
Mike Looijmans f9f8b33d37 hwmon: (max6650) Add initial rpm target devicetree documentation
Add devicetree property for early initialization of the fan controller
to prevent overheating, for example when resetting the board while the
fan was completely turned off.

Signed-off-by: Mike Looijmans <mike.looijmans@topic.nl>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2016-09-08 21:34:17 -07:00

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Text

Bindings for MAX6651 and MAX6650 I2C fan controllers
Reference:
[1] https://datasheets.maximintegrated.com/en/ds/MAX6650-MAX6651.pdf
Required properties:
- compatible : One of "maxim,max6650" or "maxim,max6651"
- reg : I2C address, one of 0x1b, 0x1f, 0x4b, 0x48.
Optional properties, default is to retain the chip's current setting:
- maxim,fan-microvolt : The supply voltage of the fan, either 5000000 uV or
12000000 uV.
- maxim,fan-prescale : Pre-scaling value, as per datasheet [1]. Lower values
allow more fine-grained control of slower fans.
Valid: 1, 2, 4, 8, 16.
- maxim,fan-target-rpm: Initial requested fan rotation speed. If specified, the
driver selects closed-loop mode and the requested speed.
This ensures the fan is already running before userspace
takes over.
Example:
fan-max6650: max6650@1b {
reg = <0x1b>;
compatible = "maxim,max6650";
maxim,fan-microvolt = <12000000>;
maxim,fan-prescale = <4>;
maxim,fan-target-rpm = <1200>;
};