Re: (EXT) Re: [PATCH 1/4] pwm: pca9685: remove unused duty_cycle struct element

Sven Van Asbroeck
2020-04-03T23:50:20Z

On Mon, Mar 30, 2020 at 11:12 AM Clemens Gruber
<clemens.gruber@pqgruber.com> wrote:
>
> On Wed, Feb 26, 2020 at 06:03:02PM +0100, Matthias Schiffer wrote:
> > As it turns out, this driver is broken in yet another way I didn't find
> > before: For changing the global prescaler the chip needs to be put into
> > sleep mode, but the driver doesn't follow the restart sequence
> > described in the datasheet when waking it back up. In consequence,
> > changing the period of one PWM does not only modify the period of all
> > PWMs (which is bad enough, but can't be avoided with this hardware),
> > but it also leaves all PWMs disabled...
>
> I am unable to reproduce this: If I set a specific duty cycle on a
> channel and then change the period, the channel stays active.
> I can see the brightness of an LED decrease if I increase the period.

What happens when pwm channels 0 and 1 are both enabled, and
you change the pwm period of channel 0. Does channel 1 remain
on?