Kernel driver pwm-fan

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

Author: Kamil Debski <>


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

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