Brussels / 4 & 5 February 2023


Pulse-Width-Modulation (PWM) is easy, isn't it?

Turning it off and on again

There is quite a good chance that you have a PWM in your pocket: A PWM is the hardware unit drives the dimmable backlight for your phone's touch display.

While it's just about emitting a periodic signal out of a single hardware pin, there is a surprising variance in the way different hardware implement a PWM.

After a brief introduction about what a PWM actually is and the common use cases the talk demonstrates the challenges of the PWM framework by presenting a few different hardware implementations and showing how the kernel's PWM API covers the whole zoo of PWM implementations.

The talk concludes with an outlook on plans to further develop the API to be able to cover more use cases.

The audience learns the general concept of PWMs, about the corner cases in their usage and driver design, and how to avoid the common pitfalls often pointed out to authors of new PWM drivers during the review process.


Uwe Kleine-König