linux-kernel - RE: [PATCH v4 4/9] usb: ehci-s5p: Change to use phy provided by the generic phy framework

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Date:	Fri, 06 Dec 2013 14:19:05 +0100
From:	Kamil Debski <k.debski@...sung.com>
To:	'Alan Stern' <stern@...land.harvard.edu>
Cc:	linux-kernel@...r.kernel.org, linux-samsung-soc@...r.kernel.org,
	linux-usb@...r.kernel.org, devicetree@...r.kernel.org,
	kyungmin.park@...sung.com, kishon@...com,
	Tomasz Figa <t.figa@...sung.com>,
	Sylwester Nawrocki <s.nawrocki@...sung.com>,
	Marek Szyprowski <m.szyprowski@...sung.com>,
	gautam.vivek@...sung.com, mat.krawczuk@...il.com,
	yulgon.kim@...sung.com, p.paneri@...sung.com,
	av.tikhomirov@...sung.com, jg1.han@...sung.com,
	galak@...eaurora.org, matt.porter@...aro.org
Subject: RE: [PATCH v4 4/9] usb: ehci-s5p: Change to use phy provided by the
 generic phy framework

Hi Alan,

Thank you for the review. Please find my replies inline.

> From: Alan Stern [mailto:stern@...land.harvard.edu]
> Sent: Thursday, December 05, 2013 7:53 PM
> 
> On Thu, 5 Dec 2013, Kamil Debski wrote:
> 
> > Change the phy provider used from the old usb phy specific to a new
> > one using the generic phy framework.
> >
> > Signed-off-by: Kamil Debski <k.debski@...sung.com>
> > Signed-off-by: Kyungmin Park <kyungmin.park@...sung.com>
> 
> > --- a/drivers/usb/host/ehci-exynos.c
> > +++ b/drivers/usb/host/ehci-exynos.c
> 
> > @@ -42,10 +42,10 @@
> >  static const char hcd_name[] = "ehci-exynos";  static struct
> > hc_driver __read_mostly exynos_ehci_hc_driver;
> >
> > +#define PHY_NUMBER 3
> >  struct exynos_ehci_hcd {
> >  	struct clk *clk;
> > -	struct usb_phy *phy;
> > -	struct usb_otg *otg;
> 
> Are you sure you want to remove that line?

Yes, I am. The new generic phy interface does not have the otg field in it.
 
> > +	struct phy *phy[PHY_NUMBER];
> >  };
> >
> >  #define to_exynos_ehci(hcd) (struct exynos_ehci_hcd
> > *)(hcd_to_ehci(hcd)->priv)
> 
> > @@ -102,13 +132,24 @@ static int exynos_ehci_probe(struct
> platform_device *pdev)
> >  					"samsung,exynos5440-ehci"))
> >  		goto skip_phy;
> >
> > -	phy = devm_usb_get_phy(&pdev->dev, USB_PHY_TYPE_USB2);
> > -	if (IS_ERR(phy)) {
> > -		usb_put_hcd(hcd);
> > -		dev_warn(&pdev->dev, "no platform data or transceiver
> defined\n");
> > -		return -EPROBE_DEFER;
> > -	} else {
> > -		exynos_ehci->phy = phy;
> > +	for_each_available_child_of_node(pdev->dev.of_node, child) {
> > +		err = of_property_read_u32(child, "reg", &phy_number);
> > +		if (err) {
> > +			dev_err(&pdev->dev, "Failed to parse device
tree\n");
> > +			return err;
> > +		}
> > +		if (phy_number >= PHY_NUMBER) {
> > +			dev_err(&pdev->dev, "Failed to parse device tree -
> number out of range\n");
> > +			return -EINVAL;
> 
> Do you need to call of_node_put(child) before each of these return
> statements?

You are right, thank you for spotting this.

> 
> > +		}
> > +		phy = devm_of_phy_get(&pdev->dev, child, 0);
> > +		of_node_put(child);
> > +		if (IS_ERR(phy)) {
> > +			dev_err(&pdev->dev, "Failed to get phy number %d",
> > +								phy_number);
> > +			return PTR_ERR(phy);
> > +		}
> > +		exynos_ehci->phy[phy_number] = phy;
> >  		exynos_ehci->otg = phy->otg;
> 
> Did you intend to remove this line?  Above, you removed the
> exynos_ehci->otg field.  I can't see how this patch would ever compile
> without an error.

Yes, I had this in a separate fix patch which I forgot to squash. Sorry for
this.

> >  	}
> >
> > @@ -149,11 +190,11 @@ skip_phy:
> >  		goto fail_io;
> >  	}
> >
> > -	if (exynos_ehci->otg)
> > -		exynos_ehci->otg->set_host(exynos_ehci->otg, &hcd->self);
> > -
> > -	if (exynos_ehci->phy)
> > -		usb_phy_init(exynos_ehci->phy);
> > +	err = exynos_phys_on(exynos_ehci->phy);
> > +	if (err) {
> > +		dev_err(&pdev->dev, "Failed to enabled phys\n");
> > +		goto fail_phys_on;
> 
> Why add a new statement label?  Just goto fail_io.

To me it seemed better to add a new label. I will drop it and use
goto fail_io, as you suggested.

> 
> > +	}
> >
> >  	ehci = hcd_to_ehci(hcd);
> >  	ehci->caps = hcd->regs;
> > @@ -172,8 +213,8 @@ skip_phy:
> >  	return 0;
> >
> >  fail_add_hcd:
> > -	if (exynos_ehci->phy)
> > -		usb_phy_shutdown(exynos_ehci->phy);
> > +	exynos_phys_off(exynos_ehci->phy);
> > +fail_phys_on:
> >  fail_io:
> >  	clk_disable_unprepare(exynos_ehci->clk);
> >  fail_clk:
> 
> Alan Stern

Best wishes,
-- 
Kamil Debski
Samsung R&D Institute Poland

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