Hello,
On Mon, Oct 26, 2015 at 08:08:58PM -0600, Stephen Warren wrote:
> On 10/26/2015 03:28 AM, Alexander Aring wrote:
> > This patch changes devm_phy_get to devm_phy_optional_get. Which fixes the
> > error handling when trying to get the phy. Currently on all errors we
> > try to look for an old style USB PHY. With this patch we try to look for
> > an old USB PHY when devm_phy_get returns -ENOENT only. Other values like
> > -EPROBE_DEFER need to be returned from the probe function, because it
> > could be that a phy is specified but not probed before.
>
> > diff --git a/drivers/usb/dwc2/platform.c b/drivers/usb/dwc2/platform.c
>
> > @@ -222,12 +222,15 @@ static int dwc2_driver_probe(struct platform_device *dev)
> >
> > hsotg->dr_mode = of_usb_get_dr_mode(dev->dev.of_node);
> >
> > + phy = devm_phy_optional_get(&dev->dev, "usb2-phy");
> > + if (IS_ERR(phy))
> > + return PTR_ERR(phy);
>
> Here, phy is checked using IS_ERR(), ...
IS_ERR(phy) is true, if something went wrong getting a phy (probably
from dt).
> > /*
> > * Attempt to find a generic PHY, then look for an old style
> > * USB PHY
> > */
> > - phy = devm_phy_get(&dev->dev, "usb2-phy");
> > - if (IS_ERR(phy)) {
> > + if (!phy) {
>
> ... and here the same phy value is checked against NULL. Hopefully,
and phy is NULL if dt didn't specify a phy. That's the semantic of
devm_phy_optional_get (which is identically to what
devm_gpiod_get_optional) does.
> devm_phy_get() doesn't actually return either an ERR value or a NULL
> pointer as errors, but restricts itself to either an ERR value or
The relevant part is that for a function with "optinal" in it's name not
finding the respective resource isn't an error. So checking for NULL
isn't error handling but handling the 2nd valid case.
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | http://www.pengutronix.de/ |
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