|  | 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 <k.debski@samsung.com> | 
|  |  | 
|  | Description | 
|  | ----------- | 
|  |  | 
|  | 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. |