PWM controller driver

As you need struct gpio_chip when writing GPIO-controller drivers and struct irq_chip when writing IRQ-controller drivers, a PWM controller is represented in the kernel as an instance of the struct pwm_chip structure:

struct pwm_chip { 
   struct device *dev; 
   const struct pwm_ops *ops; 
   int base; 
   unsigned int npwm; 
 
   struct pwm_device *pwms; 
   struct pwm_device * (*of_xlate)(struct pwm_chip *pc, 
                    const struct of_phandle_args *args); 
   unsigned int of_pwm_n_cells; 
   bool can_sleep; 
}; 

The following is the meaning of each element in the structure:

• dev: This represents the device associated with this chip.
• Ops: This is a data structure providing callback functions this chip exposes to consumer drivers.
• Base: This is the number of the first PWM controlled by this chip. If chip->base...