Hi Christophe,
On Sat, 2 Mar 2024 at 21:19, Christophe JAILLET
<christophe.jaillet@xxxxxxxxxx> wrote:
>
> Le 01/03/2024 à 20:38, Anand Moon a écrit :
> > The devm_clk_get_enabled() helpers:
> > - call devm_clk_get()
> > - call clk_prepare_enable() and register what is needed in order to
> > call clk_disable_unprepare() when needed, as a managed resource.
> >
> > This simplifies the code and avoids the calls to clk_disable_unprepare().
> >
> > While at it, use dev_err_probe consistently, and use its return value
> > to return the error code.
> >
> > Signed-off-by: Anand Moon <linux.amoon@xxxxxxxxx>
> > ---
> > drivers/usb/host/ehci-exynos.c | 30 +++++-------------------------
> > 1 file changed, 5 insertions(+), 25 deletions(-)
> >
> > diff --git a/drivers/usb/host/ehci-exynos.c b/drivers/usb/host/ehci-exynos.c
> > index f644b131cc0b..05aa3d9c2a3b 100644
> > --- a/drivers/usb/host/ehci-exynos.c
> > +++ b/drivers/usb/host/ehci-exynos.c
> > @@ -159,19 +159,12 @@ static int exynos_ehci_probe(struct platform_device *pdev)
> >
> > err = exynos_ehci_get_phy(&pdev->dev, exynos_ehci);
> > if (err)
> > - goto fail_clk;
> > -
> > - exynos_ehci->clk = devm_clk_get(&pdev->dev, "usbhost");
> > -
> > - if (IS_ERR(exynos_ehci->clk)) {
> > - dev_err(&pdev->dev, "Failed to get usbhost clock\n");
> > - err = PTR_ERR(exynos_ehci->clk);
> > - goto fail_clk;
> > - }
> > + goto fail_io;
> >
> > - err = clk_prepare_enable(exynos_ehci->clk);
> > - if (err)
> > - goto fail_clk;
> > + exynos_ehci->clk = devm_clk_get_enabled(&pdev->dev, "usbhost");
> > + if (IS_ERR(exynos_ehci->clk))
> > + return dev_err_probe(&pdev->dev, PTR_ERR(exynos_ehci->clk),
> > + "Failed to get usbhost clock\n");
> >
> > hcd->regs = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
> > if (IS_ERR(hcd->regs)) {
> > @@ -223,8 +216,6 @@ static int exynos_ehci_probe(struct platform_device *pdev)
> > exynos_ehci_phy_disable(&pdev->dev);
> > pdev->dev.of_node = exynos_ehci->of_node;
> > fail_io:
> > - clk_disable_unprepare(exynos_ehci->clk);
> > -fail_clk:
> > usb_put_hcd(hcd);
> > return err;
> > }
> > @@ -240,8 +231,6 @@ static void exynos_ehci_remove(struct platform_device *pdev)
> >
> > exynos_ehci_phy_disable(&pdev->dev);
> >
> > - clk_disable_unprepare(exynos_ehci->clk);
> > -
> > usb_put_hcd(hcd);
> > }
> >
> > @@ -249,7 +238,6 @@ static void exynos_ehci_remove(struct platform_device *pdev)
> > static int exynos_ehci_suspend(struct device *dev)
> > {
> > struct usb_hcd *hcd = dev_get_drvdata(dev);
> > - struct exynos_ehci_hcd *exynos_ehci = to_exynos_ehci(hcd);
> >
> > bool do_wakeup = device_may_wakeup(dev);
> > int rc;
> > @@ -260,25 +248,17 @@ static int exynos_ehci_suspend(struct device *dev)
> >
> > exynos_ehci_phy_disable(dev);
> >
> > - clk_disable_unprepare(exynos_ehci->clk);
>
> Hi,
>
> I don't think that removing clk_[en|dis]abble from the suspend and
> resume function is correct.
>
> The goal is to stop some hardware when the system is suspended, in order
> to save some power.
Yes correct,
>
> Why did you removed it?
>
devm_clk_get_enabled function register callback for clk_prepare_enable
and clk_disable_unprepare, so when the clock resource is not used it should get
disabled.
[0] https://elixir.bootlin.com/linux/latest/source/drivers/clk/clk-devres.c#L75
I have also tested with rtc suspend & resume and did not find any issue.
> CJ
Thanks
-Anand
>
> > -
> > return rc;
> > }
> >
> > static int exynos_ehci_resume(struct device *dev)
> > {
> > struct usb_hcd *hcd = dev_get_drvdata(dev);
> > - struct exynos_ehci_hcd *exynos_ehci = to_exynos_ehci(hcd);
> > int ret;
> >
> > - ret = clk_prepare_enable(exynos_ehci->clk);
> > - if (ret)
> > - return ret;
> > -
> > ret = exynos_ehci_phy_enable(dev);
> > if (ret) {
> > dev_err(dev, "Failed to enable USB phy\n");
> > - clk_disable_unprepare(exynos_ehci->clk);
> > return ret;
> > }
> >
>
