Linux Device Drivers Development

PWM Drivers

Pulse Wide Modulation (PWM) operates like a switch that constantly cycles on and off. It is a hardware feature used to control servomotors, for voltage regulation and so on. The most well-known applications of PWM are:

• Motor speed control
• Light dimming
• Voltage regulation

Now, let's introduce PWM with a simple diagram:

The preceding figure illustrates a complete PWM cycle, introducing some terms that we need to clarify prior to getting deeper into the kernel PWM framework:

• Ton: This is the duration during which the signal is high.
• Toff: This is the duration during which the signal is low.
• Period: This is the duration of a complete ...