[PATCH V4 4/5] gpio: gpio-xilinx: Add support for suspend and resume
Linus Walleij
linus.walleij at linaro.org
Fri Jan 8 19:25:51 EST 2021
On Fri, Jan 8, 2021 at 12:41 PM Srinivas Neeli <sneeli at xilinx.com> wrote:
> > On Wed, Jan 6, 2021 at 1:27 PM Srinivas Neeli <srinivas.neeli at xilinx.com>
> > wrote:
> > > /**
> > > * xgpio_remove - Remove method for the GPIO device.
> > > * @pdev: pointer to the platform device @@ -289,7 +323,10 @@ static
> > > int xgpio_remove(struct platform_device *pdev) {
> > > struct xgpio_instance *gpio = platform_get_drvdata(pdev);
> > >
> > > - clk_disable_unprepare(gpio->clk);
> > > + if (!pm_runtime_suspended(&pdev->dev))
> > > + clk_disable_unprepare(gpio->clk);
> > > +
> > > + pm_runtime_disable(&pdev->dev);
> >
> > This looks complex and racy. What if the device is resumed after you
> > executed the first part of the statement.
>
> Could you please explain more on this.
> What is the need to call pm_runtime_get_sync(); in remove API ?
I explain that on the lines right below your comment ;D
> > The normal sequence is:
> >
> > pm_runtime_get_sync(dev);
> > pm_runtime_put_noidle(dev);
> > pm_runtime_disable(dev);
> >
> > This will make sure the clock is enabled and pm runtime is disabled.
> > After this you can unconditionally call clk_disable_unprepare(gpio->clk);
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Yours,
Linus Walleij
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