Re: [PATCH 3/3] usb: dwc3: keystone: Turn on USB3 PHY before controller

[Roger Quadros]

On 14/05/2020 04:37, Chunfeng Yun wrote:
> On Wed, 2020-05-13 at 16:07 +0300, Roger Quadros wrote:
> > The Local Power Sleep Controller (LPSC) dependency on AM65
> > requires SERDES0 to be powered on before USB.
> >
> > We need to power up SERDES0 power domain and hold it on
> > throughout the reset, init, power on sequence.
> >
> > Signed-off-by: Roger Quadros <rogerq@xxxxxx>
> > ---
> >   drivers/usb/dwc3/dwc3-keystone.c | 47 +++++++++++++++++++++++++++++++-
> >   1 file changed, 46 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/usb/dwc3/dwc3-keystone.c b/drivers/usb/dwc3/dwc3-keystone.c
> > index 1e14a6f4884b..46d46f3507fc 100644
> > --- a/drivers/usb/dwc3/dwc3-keystone.c
> > +++ b/drivers/usb/dwc3/dwc3-keystone.c
> > @@ -14,6 +14,7 @@
> >   #include <linux/dma-mapping.h>
> >   #include <linux/io.h>
> >   #include <linux/of_platform.h>
> > +#include <linux/phy/phy.h>
> >   #include <linux/pm_runtime.h>
> >   
> >   /* USBSS register offsets */
> > @@ -34,6 +35,7 @@
> >   struct dwc3_keystone {
> >   	struct device			*dev;
> >   	void __iomem			*usbss;
> > +	struct phy			*usb3_phy;
> >   };
> >   
> >   static inline u32 kdwc3_readl(void __iomem *base, u32 offset)
> > @@ -95,8 +97,44 @@ static int kdwc3_probe(struct platform_device *pdev)
> >   	if (IS_ERR(kdwc->usbss))
> >   		return PTR_ERR(kdwc->usbss);
> >   
> > -	pm_runtime_enable(kdwc->dev);
> > +	/* PSC dependency on AM65 needs SERDES0 to be powered before USB0 */
> > +	kdwc->usb3_phy = devm_phy_get(dev, "usb3-phy");
> Use devm_phy_optional_get() instead?

Indeed, it seems better suited.

cheers,
-roger

> > +	if (IS_ERR(kdwc->usb3_phy)) {
> > +		error = PTR_ERR(kdwc->usb3_phy);
> > +		if (error == -ENOSYS || error == -ENODEV) {
> > +			kdwc->usb3_phy = NULL;
> > +		} else {
> > +			if (error != -EPROBE_DEFER) {
> > +				dev_err(dev, "couldn't get usb3 phy: %d\n",
> > +					error);
> > +			}
> > +
> > +			return error;
> > +		}
> > +	}
> > +
> > +	phy_pm_runtime_get_sync(kdwc->usb3_phy);
> > +
> > +	error = phy_reset(kdwc->usb3_phy);
> > +	if (error < 0) {
> > +		dev_err(dev, "usb3 phy reset failed: %d\n", error);
> > +		return error;
> > +	}
> > +
> > +	error = phy_init(kdwc->usb3_phy);
> > +	if (error < 0) {
> > +		dev_err(dev, "usb3 phy init failed: %d\n", error);
> > +		return error;
> > +	}
> >   
> > +	error = phy_power_on(kdwc->usb3_phy);
> > +	if (error < 0) {
> > +		dev_err(dev, "usb3 phy power on failed: %d\n", error);
> > +		phy_exit(kdwc->usb3_phy);
> > +		return error;
> > +	}
> > +
> > +	pm_runtime_enable(kdwc->dev);
> >   	error = pm_runtime_get_sync(kdwc->dev);
> >   	if (error < 0) {
> >   		dev_err(kdwc->dev, "pm_runtime_get_sync failed, error %d\n",
> > @@ -138,6 +176,9 @@ static int kdwc3_probe(struct platform_device *pdev)
> >   err_irq:
> >   	pm_runtime_put_sync(kdwc->dev);
> >   	pm_runtime_disable(kdwc->dev);
> > +	phy_power_off(kdwc->usb3_phy);
> > +	phy_exit(kdwc->usb3_phy);
> > +	phy_pm_runtime_put_sync(kdwc->usb3_phy);
> >   
> >   	return error;
> >   }
> > @@ -163,6 +204,10 @@ static int kdwc3_remove(struct platform_device *pdev)
> >   	pm_runtime_put_sync(kdwc->dev);
> >   	pm_runtime_disable(kdwc->dev);
> >   
> > +	phy_power_off(kdwc->usb3_phy);
> > +	phy_exit(kdwc->usb3_phy);
> > +	phy_pm_runtime_put_sync(kdwc->usb3_phy);
> > +
> >   	platform_set_drvdata(pdev, NULL);
> >   
> >   	return 0;

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