RE: [PATCH 4/4] usb: gadget: udc: renesas_usb3: should call devm_phy_get() before add udc

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Hi Simon-san,

> From: Simon Horman, Sent: Monday, April 9, 2018 8:58 PM
> 
> On Mon, Apr 02, 2018 at 09:21:34PM +0900, Yoshihiro Shimoda wrote:
> > This patch fixes an issue that this driver cannot call phy_init()
> > if a gadget driver is alreadly loaded because usb_add_gadget_udc()
> > might call renesas_usb3_start() via .udc_start.
> >
> > Fixes: 279d4bc64060 ("usb: gadget: udc: renesas_usb3: add support for generic phy")
> > Cc: <stable@xxxxxxxxxxxxxxx> # v4.15+
> > Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
> > ---
> >  drivers/usb/gadget/udc/renesas_usb3.c | 16 ++++++++--------
> >  1 file changed, 8 insertions(+), 8 deletions(-)
> 
> Reviewed-by: Simon Horman <horms+renesas@xxxxxxxxxxxx>
> 
> 
> Please see some suggestions for follow-up lower-priority patches below.

Thank you for the review and suggestions!

> >
> > diff --git a/drivers/usb/gadget/udc/renesas_usb3.c b/drivers/usb/gadget/udc/renesas_usb3.c
> > index 738b734..671bac3 100644
> > --- a/drivers/usb/gadget/udc/renesas_usb3.c
> > +++ b/drivers/usb/gadget/udc/renesas_usb3.c
> > @@ -2632,6 +2632,14 @@ static int renesas_usb3_probe(struct platform_device *pdev)
> >  	if (ret < 0)
> >  		goto err_alloc_prd;
> >
> > +	/*
> > +	 * This is an optional. So, if this driver cannot get a phy,
> > +	 * this driver will not handle a phy anymore.
> > +	 */
> 
> nit: s/an optional/optional/

Oops. I will fix and submit v2 patches.

> > +	usb3->phy = devm_phy_get(&pdev->dev, "usb");
> > +	if (IS_ERR(usb3->phy))
> > +		usb3->phy = NULL;
> 
> I think this will unintentionally ignore errors other than the
> non-existence of the device, f.e. a memory allocation failure
> in devm_phy_get().
> 
> So perhaps something like this, as per phy_optional_get(), would be better?
> 
> 	usb3->phy = devm_phy_get(&pdev->dev, "usb");
> 	if (IS_ERR(usb3->phy) && (PTR_ERR(usb3->phy) == -ENODEV))
> 		usb3->phy = NULL;

Thank you for the suggestion. I agree with you.
I think I should use devm_phy_optional_get() instead of dev_phy_get(), as you mentioned :)
So, I will fix the code by using devm_phy_optional_get() first, and then fix this.

Best regards,
Yoshihiro Shimoda

> > +
> >  	pm_runtime_enable(&pdev->dev);
> >  	ret = usb_add_gadget_udc(&pdev->dev, &usb3->gadget);
> >  	if (ret < 0)
> > @@ -2641,14 +2649,6 @@ static int renesas_usb3_probe(struct platform_device *pdev)
> >  	if (ret < 0)
> >  		goto err_dev_create;
> >
> > -	/*
> > -	 * This is an optional. So, if this driver cannot get a phy,
> > -	 * this driver will not handle a phy anymore.
> > -	 */
> > -	usb3->phy = devm_phy_get(&pdev->dev, "usb");
> > -	if (IS_ERR(usb3->phy))
> > -		usb3->phy = NULL;
> > -
> >  	usb3->workaround_for_vbus = priv->workaround_for_vbus;
> >
> >  	renesas_usb3_debugfs_init(usb3, &pdev->dev);
> > --
> > 1.9.1
> >




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