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SubjectRe: [RESEND PATCH v2 7/7] usb: xhci: plat: add vbus regulator control
Dear Mark,

On Wed, 27 Apr 2016 10:57:39 +0100 Mark Brown wrote:

> On Wed, Apr 27, 2016 at 08:37:20AM +0300, Felipe Balbi wrote:
> > Jisheng Zhang <jszhang@marvell.com> writes:
>
> > > + vbus = devm_regulator_get(&pdev->dev, "vbus");
>
> > devm_regulator_get_optional() ??
>
> Does USB work without a VBUS? Unless the answer is yes then I'd expect
> this to be just a normal regulator_get().

Per spec no. But the vbus may be transparent to SW on some platforms, so I
think devm_regulator_get_optional() is better.

>
> >
> > > + if (PTR_ERR(vbus) == -ENODEV) {
> > > + vbus = NULL;
> > > + } else if (IS_ERR(vbus)) {
> > > + ret = PTR_ERR(vbus);
> > > + goto disable_clk;
> > > + } else if (vbus) {
> > > + ret = regulator_enable(vbus);
> > > + if (ret) {
> > > + dev_err(&pdev->dev,
> > > + "failed to enable usb vbus regulator: %d\n",
> > > + ret);
> > > + goto disable_clk;
> > > + }
> > > + }
>
> This is all completely broken unless the supply is optional.

The supply is optional.

Thanks for your review,
Jisheng

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