Kernel driver pwm-fan

This driver enables the use of a PWM module to drive a fan. It uses thegeneric PWM interface thus it is hardware independent. It can be used onmany SoCs, as long as the SoC supplies a PWM line driver that exposesthe generic PWM API.

Author: Kamil Debski <k.debski@samsung.com>

Description

The driver implements a simple interface for driving a fan connected toa PWM output. It uses the generic PWM interface, thus it can be used witha range of SoCs. The driver exposes the fan to the user space throughthe hwmon’s sysfs interface.

The fan rotation speed returned via the optional ‘fan1_input’ is extrapolatedfrom the sampled interrupts from the tachometer signal within 1 second.