linux-kernel - Re: [RESEND PATCH v2 2/7] usb: xhci: plat: attach the usb

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Message-ID: <20160427135946.3b983890@xhacker>
Date:	Wed, 27 Apr 2016 13:59:46 +0800
From:	Jisheng Zhang <jszhang@...vell.com>
To:	Felipe Balbi <felipe.balbi@...ux.intel.com>
CC:	<mathias.nyman@...el.com>, <gregkh@...uxfoundation.org>,
	<linux-usb@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<linux-arm-kernel@...ts.infradead.org>,
	<yendapally.reddy@...adcom.com>,
	Maxime Ripard <maxime.ripard@...e-electrons.com>,
	Mathias Nyman <mathias.nyman@...ux.intel.com>
Subject: Re: [RESEND PATCH v2 2/7] usb: xhci: plat: attach the usb_phy to
 the correct hcd

Dear Felipe,

On Wed, 27 Apr 2016 08:29:34 +0300 Felipe Balbi wrote:

> Hi,
> 
> (Cc authors and maintainer, otherwise you're patch might be forgotten ;-)

Thanks a lot for the kind remind. I just run get_maintainer.pl to get the
To and Cc lists. It seems Mathias's email changed, MAINTAINERS need to updated.

> 
> Jisheng Zhang <jszhang@...vell.com> writes:
> > Commit 7b8ef22ea547 ("usb: xhci: plat: Add USB phy support") adds the
> > usb_phy for usb3, but it attached the usb_phy to incorrect hcd. The  
> 
> where did you see that's the USB3 phy ? I can't see it.

Commit 7b8ef22ea547 ("usb: xhci: plat: Add USB phy support") says:

"The Marvell Armada 385 AP needs a dumb phy in order to enable the USB3 VBUS."

So I think it means USB3 phy.

Here I have two questions: Per my understanding, usb_phy is deprecated, all
users and new code are encouraged to use generic phy. I think there must
be some special reason commit 7b8ef22ea547 still made use of usb_phy, could
I know what's the reason?

And could the "USB3 VBUS" support be achieved through regulator framework?

Thanks in advance,
Jisheng


> 
> > xhci->shared_hcd is the hcd for usb3, this patch fixes this issue
> > by attach the usb_phy to the xhci->shared_hcd.  
> 
> Fixes: 7b8ef22ea547 ("usb: xhci: plat: Add USB phy support")
> Cc: <stable@...r.kernel.org # v4.1+
> 
> Maxime, any comments ? It _is_ odd that only one PHY got added.
> 
> > Signed-off-by: Jisheng Zhang <jszhang@...vell.com>
> > ---
> >  drivers/usb/host/xhci-plat.c | 16 +++++++++-------
> >  1 file changed, 9 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/usb/host/xhci-plat.c b/drivers/usb/host/xhci-plat.c
> > index 8cb46cb..9ff89e9 100644
> > --- a/drivers/usb/host/xhci-plat.c
> > +++ b/drivers/usb/host/xhci-plat.c
> > @@ -144,6 +144,7 @@ static int xhci_plat_probe(struct platform_device *pdev)
> >  	struct resource         *res;
> >  	struct usb_hcd		*hcd;
> >  	struct clk              *clk;
> > +	struct usb_phy		*usb_phy;
> >  	int			ret;
> >  	int			irq;
> >  
> > @@ -231,17 +232,18 @@ static int xhci_plat_probe(struct platform_device *pdev)
> >  	if (HCC_MAX_PSA(xhci->hcc_params) >= 4)
> >  		xhci->shared_hcd->can_do_streams = 1;
> >  
> > -	hcd->usb_phy = devm_usb_get_phy_by_phandle(&pdev->dev, "usb-phy", 0);
> > -	if (IS_ERR(hcd->usb_phy)) {
> > -		ret = PTR_ERR(hcd->usb_phy);
> > +	usb_phy = devm_usb_get_phy_by_phandle(&pdev->dev, "usb-phy", 0);
> > +	if (IS_ERR(usb_phy)) {
> > +		ret = PTR_ERR(usb_phy);
> >  		if (ret == -EPROBE_DEFER)
> >  			goto put_usb3_hcd;
> > -		hcd->usb_phy = NULL;
> > +		usb_phy = NULL;
> >  	} else {
> > -		ret = usb_phy_init(hcd->usb_phy);
> > +		ret = usb_phy_init(usb_phy);
> >  		if (ret)
> >  			goto put_usb3_hcd;
> >  	}
> > +	xhci->shared_hcd->usb_phy = usb_phy;
> >  
> >  	ret = usb_add_hcd(hcd, irq, IRQF_SHARED);
> >  	if (ret)
> > @@ -258,7 +260,7 @@ dealloc_usb2_hcd:
> >  	usb_remove_hcd(hcd);
> >  
> >  disable_usb_phy:
> > -	usb_phy_shutdown(hcd->usb_phy);
> > +	usb_phy_shutdown(usb_phy);
> >  
> >  put_usb3_hcd:
> >  	usb_put_hcd(xhci->shared_hcd);
> > @@ -280,7 +282,7 @@ static int xhci_plat_remove(struct platform_device *dev)
> >  	struct clk *clk = xhci->clk;
> >  
> >  	usb_remove_hcd(xhci->shared_hcd);
> > -	usb_phy_shutdown(hcd->usb_phy);
> > +	usb_phy_shutdown(xhci->shared_hcd->usb_phy);
> >  
> >  	usb_remove_hcd(hcd);
> >  	usb_put_hcd(xhci->shared_hcd);
> > -- 
> > 2.8.1
> >
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-usb" in
> > the body of a message to majordomo@...r.kernel.org
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html  
>