linux-kernel - Re: [RESEND PATCH v2 7/7] usb: xhci: plat: add vbus regulator control

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Message-ID: <20160427095738.GG3217@sirena.org.uk>
Date:	Wed, 27 Apr 2016 10:57:39 +0100
From:	Mark Brown <broonie@...nel.org>
To:	Felipe Balbi <felipe.balbi@...ux.intel.com>
Cc:	Jisheng Zhang <jszhang@...vell.com>, mathias.nyman@...ux.intel.com,
	gregkh@...uxfoundation.org, linux-usb@...r.kernel.org,
	linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	yendapally.reddy@...adcom.com
Subject: Re: [RESEND PATCH v2 7/7] usb: xhci: plat: add vbus regulator control

On Wed, Apr 27, 2016 at 08:37:20AM +0300, Felipe Balbi wrote:
> Jisheng Zhang <jszhang@...vell.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().

> 
> > +	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.

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