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Message-ID: <20140912102828.GB2463@peterchendt>
Date: Fri, 12 Sep 2014 18:28:29 +0800
From: Peter Chen <peter.chen@...escale.com>
To: Antoine Tenart <antoine.tenart@...e-electrons.com>
CC: "balbi@...com" <balbi@...com>,
"gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>,
"kishon@...com" <kishon@...com>,
"stern@...land.harvard.edu" <stern@...land.harvard.edu>,
"sergei.shtylyov@...entembedded.com"
<sergei.shtylyov@...entembedded.com>,
"yoshihiro.shimoda.uh@...esas.com" <yoshihiro.shimoda.uh@...esas.com>,
"alexandre.belloni@...e-electrons.com"
<alexandre.belloni@...e-electrons.com>,
"thomas.petazzoni@...e-electrons.com"
<thomas.petazzoni@...e-electrons.com>,
"zmxu@...vell.com" <zmxu@...vell.com>,
"jszhang@...vell.com" <jszhang@...vell.com>,
"linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v4 9/9] usb: chipidea: add support to the generic PHY
framework in ChipIdea
On Fri, Sep 12, 2014 at 11:35:50AM +0200, Antoine Tenart wrote:
> On Fri, Sep 12, 2014 at 05:27:13PM +0800, Peter Chen wrote:
> > On Fri, Sep 12, 2014 at 10:21:25AM +0200, Antoine Tenart wrote:
> > > Peter,
> > >
> > > On Fri, Sep 12, 2014 at 01:10:33AM +0000, Peter Chen wrote:
> > > > > On Thu, Sep 11, 2014 at 08:54:47AM +0800, Peter Chen wrote:
> > > > > > On Wed, Sep 03, 2014 at 09:40:40AM +0200, Antoine Tenart wrote:
> > > > > > > @@ -595,23 +639,27 @@ static int ci_hdrc_probe(struct platform_device
> > > > > *pdev)
> > > > > > > return -ENODEV;
> > > > > > > }
> > > > > > >
> > > > > > > - if (ci->platdata->usb_phy)
> > > > > > > + if (ci->platdata->phy)
> > > > > > > + ci->phy = ci->platdata->phy;
> > > > > > > + else if (ci->platdata->usb_phy)
> > > > > > > ci->usb_phy = ci->platdata->usb_phy;
> > > > > > > else
> > > > > > > - ci->usb_phy = devm_usb_get_phy(dev, USB_PHY_TYPE_USB2);
> > > > > > > + ci->phy = devm_phy_get(dev, "usb-phy");
> > > > > > >
> > > > > > > - if (IS_ERR(ci->usb_phy)) {
> > > > > > > - ret = PTR_ERR(ci->usb_phy);
> > > > > > > + if (IS_ERR(ci->phy) || (ci->phy == NULL && ci->usb_phy == NULL)) {
> > > > > > > /*
> > > > > > > * if -ENXIO is returned, it means PHY layer wasn't
> > > > > > > * enabled, so it makes no sense to return -EPROBE_DEFER
> > > > > > > * in that case, since no PHY driver will ever probe.
> > > > > > > */
> > > > > > > - if (ret == -ENXIO)
> > > > > > > - return ret;
> > > > > > > + if (PTR_ERR(ci->phy) == -ENXIO)
> > > > > > > + return -ENXIO;
> > > > > > >
> > > > > > > - dev_err(dev, "no usb2 phy configured\n");
> > > > > > > - return -EPROBE_DEFER;
> > > > > > > + ci->usb_phy = devm_usb_get_phy(dev, USB_PHY_TYPE_USB2);
> > > > > > > + if (IS_ERR(ci->usb_phy)) {
> > > > > > > + dev_err(dev, "no usb2 phy configured\n");
> > > > > > > + return -EPROBE_DEFER;
> > > > > > > + }
> > > > > > > }
> > > > > >
> > > > > > Sorry, I can't accept this change, why devm_usb_get_phy(dev,
> > > > > > USB_PHY_TYPE_USB2) is put at error path? Since current get PHY
> > > > > > operation is a little complicated, we may have a dedicate function to do it,
> > > > > dwc3 driver is a good example.
> > > > >
> > > > > It's not the error path, it's the case when there is no PHY from the generic PHY
> > > > > framework available. Getting an USB PHY is a fallback solution.
> > > > >
> > > > > I agree we can move this to a dedicated function. But even if doing so, we'll
> > > > > have to test ci->phy first.
> > > > >
> > > > > Or do you have something else in mind?
> > > > >
> > > >
> > > > I still want devm_usb_get_phy(dev, USB_PHY_TYPE_USB2) to be called at the same place
> > > > like generic_phy, not in later error path, in error path, we only handle error.
> > >
> > > Would this fit you?
> > >
> > > if (ci->platdata->phy)
> > > ci->phy = ci->platdata->phy;
> > > else if (ci->platdata->usb_phy)
> > > ci->usb_phy = ci->platdata->usb_phy;
> > >
> > > if (ci->phy == NULL && ci->usb_phy == NULL) {
> >
> > You should use else if here.
>
> Yes, sure.
>
> >
> > > ci->phy = devm_phy_get(dev, "usb-phy");
> > > ci->usb_phy = devm_usb_get_phy(dev, USB_PHY_TYPE_USB2);
> > >
> > > /* if both generic PHY and USB PHY layers aren't enabled */
> > > if (PTR_ERR(ci->phy) == -ENOSYS && PTR_ERR(ci->usb_phy) == -ENXIO)
> > > return -ENXIO;
> > >
> > > if (IS_ERR(ci->phy) && IS_ERR(ci->usb_phy))
> > > return -EPROBE_DEFER;
> > >
> > > /* if an usb_phy is available, but no phy is there */
> > > if (PTR_ERR(ci->phy) == -ENODEV)
> > > ci->phy = NULL;
> > if (ci->phy)
> > ci->usb_phy = NULL;
> > if (ci->usb_phy)
> > ci->phy = NULL;
> >
> > How about above?
>
> When no PHY or USB PHY is found, -ENODEV is returned. Doing the above
> would always end up having ci->phy and ci->usb_phy being NULL.
When we try to get generic phy, if -ENODEV is returned, the ci->usb_phy
should not be NULL, otherwise, your the second condition will return
-EPROBE_DEFER, it means when the code goes here, there must be one PHY
is found.
>
> We could have:
>
> if (IS_ERR(ci->phy))
> ci->phy = NULL;
> else if (IS_ERR(ci->usb_phy))
> ci->usb_phy = NULL;
>
>
> Antoine
>
> --
> Antoine Ténart, Free Electrons
> Embedded Linux, Kernel and Android engineering
> http://free-electrons.com
--
Best Regards,
Peter Chen
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