Re: [PATCH 4.6 69/81] gpio: zynq: initialize clock even without CONFIG_PM

[Helmut Grohne <h.grohne@intenta.de>]

On Fri, Jul 08, 2016 at 10:23:07AM +0200, Shubhrajyoti Datta wrote:
>  A small issue
> 
> Now it will be off by 1 ie we enable twice in probe.
> 
> solution is that either there should be get_sync or clk_enable but not both.

As far as I understand the inner workings of pm_runtime_get_sync this is
not a problem.

> > +       ret = clk_prepare_enable(gpio->clk);
> > +       if (ret) {
> > +               dev_err(&pdev->dev, "Unable to enable clock.\n");
> > +               return ret;
> > +       }
> 
> This will now enable the first time.
> >
> > +       pm_runtime_set_active(&pdev->dev);
> the the pm core that it is enabled .

This function sets pdev->dev.power.runtime_status to RPM_ACTIVE (via
__update_runtime_status).

> >         pm_runtime_enable(&pdev->dev);
> >         ret = pm_runtime_get_sync(&pdev->dev);
> 
> this will enable the second time.

The bulk of the work is done by rpm_resume. Close to the top of the
function the runtime_status field is compared to RPM_ACTIVE and if so,
the resume operation is skipped.

Is there any mistake in that analysis?

Helmut