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- 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 <[email protected]>
- 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.
- The driver provides the following sensor accesses in sysfs:
- =============== ======= =======================================================
- fan1_input ro fan tachometer speed in RPM
- pwm1_enable rw keep enable mode, defines behaviour when pwm1=0
- 0 -> disable pwm and regulator
- 1 -> enable pwm; if pwm==0, disable pwm, keep regulator enabled
- 2 -> enable pwm; if pwm==0, keep pwm and regulator enabled
- 3 -> enable pwm; if pwm==0, disable pwm and regulator
- pwm1 rw relative speed (0-255), 255=max. speed.
- =============== ======= =======================================================
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