robert-hh 84302b2854 rp2/machine_pwm: Enable keyword args in constructor and add init method.
This adds support for freq/duty_u16/duty_ns keyword arguments in the PWM
constructor, and adds the PWM.init() method.  Using init() without
arguments enables a previously deinit-ed PWM again.

Further changes in this commit:
- Do not start PWM output if only duty was set.
- Stop all PWM slices on soft-reset.
- Fix a bug when changing the freq on a channel pair with duty_ns set.
2023-05-04 13:13:05 +10:00
..