Re: [PATCH v2] fpga: zynq-fpga: Enable pm_runtime (suspend, resume)

[Mike Looijmans]

ïOn 23-11-15 23:02, Moritz Fischer wrote:
> Hi Mike,
>
> thanks for your feedback. I put what I think you suggested inline below.
>
> On Thu, Nov 19, 2015 at 11:25 PM, Mike Looijmans
> <mike.looijmans@xxxxxxxx> wrote:
> > On 19-11-15 23:07, Moritz Fischer wrote:
>
> > > @@ -457,19 +457,26 @@ static int zynq_fpga_probe(struct platform_device
> > > *pdev)
> > >                  return err;
> > >          }
> > >
> > > +       pm_runtime_get_noresume(&pdev->dev);
> > > +       pm_runtime_set_active(&pdev->dev);
> > > +       pm_runtime_enable(&pdev->dev);
> > > +
> > >          /* unlock the device */
> > >          zynq_fpga_write(priv, UNLOCK_OFFSET, UNLOCK_MASK);
> > >
> > > -       clk_disable(priv->clk);
> > >
> > >          err = fpga_mgr_register(dev, "Xilinx Zynq FPGA Manager",
> > >                                  &zynq_fpga_ops, priv);
> > >          if (err) {
> > >                  dev_err(dev, "unable to register FPGA manager");
> > > -               clk_unprepare(priv->clk);
> > > +               clk_disable_unprepare(priv->clk);
> - clk_disable_unprepare(priv->clk);
> > > +               pm_runtime_put_noidle(&pdev->dev);
> > > +               pm_runtime_disable(&pdev->dev);
> > >                  return err;
> > >          }
> > >
> > > +       pm_runtime_put(&pdev->dev);
> > > +
> > >          return 0;
> > >    }
> > >
> > > @@ -483,11 +490,45 @@ static int zynq_fpga_remove(struct platform_device
> > > *pdev)
> > >
> > >          fpga_mgr_unregister(&pdev->dev);
> > >
> > > -       clk_unprepare(priv->clk);
> > > +       pm_runtime_get_sync(&pdev->dev);
> > > +       clk_disable_unprepare(priv->clk);
> - clk_disable_unprepare(priv->clk);
>
> > > +       pm_runtime_put_noidle(&pdev->dev);
> > > +       pm_runtime_disable(&pdev->dev);
> > >
> > >          return 0;
> > >    }
> > >
> > > +static int __maybe_unused zynq_fpga_runtime_suspend(struct device *dev)
> > > +{
> > > +       struct zynq_fpga_priv *priv;
> > > +       struct fpga_manager *mgr;
> > > +
> > > +       mgr = dev_get_drvdata(dev);
> > > +       priv = mgr->priv;
> > > +
> > > +       clk_disable(priv->clk);
>
> - clk_disable(priv->clk)
> + clk_disable_unprepare(priv->clk)
> >  From what I understand, this call is done in a sleepable context, so you can
> > use clk_disable_unprepare here (and its counterpart in resume). And remove
> > the prepare at probe time and unprepare at removal.
> >
> > Not all clocks can implement atomic enable/disable, for example I2C and SPI
> > controlled clocks only implement the prepare/unprepare routines.
> >
> > I guess the "clk" here will always be a SOC provided one, so it won't make
> > any difference for the Zynq, but someone is likely to some day copy/paste
> > this driver and use it for some externally connected FPGA instead.
>
> To clarify. Is the above / below what you suggested?

Indeed, that's exactly what I meant.

> > > +static int __maybe_unused zynq_fpga_runtime_resume(struct device *dev)
> > > +{
> > > +       struct zynq_fpga_priv *priv;
> > > +       struct fpga_manager *mgr;
> > > +
> > > +       mgr = dev_get_drvdata(dev);
> > > +       priv = mgr->priv;
> > > +
> > > +       clk_enable(priv->clk);
>
> - clk_enable(priv->clk)
> + clk_prepare_enable(priv->clk)
> > > +
> > > +       return 0;
> > > +}
> > > +
>
> Cheers,
>
> Moritz



Kind regards,

Mike Looijmans
System Expert

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