Re: [PATCH 7/7] usb: host: ohci-exynos: Convert to devm_of_phy_optional_get()

[Rob Herring <robh@kernel.org>]

On Wed, Jan 18, 2023 at 12:28 PM Geert Uytterhoeven
<geert@linux-m68k.org> wrote:
>
> Hi Rob,
>
> On Wed, Jan 18, 2023 at 6:30 PM Rob Herring <robh@kernel.org> wrote:
> > On Wed, Jan 18, 2023 at 4:15 AM Geert Uytterhoeven
> > <geert+renesas@glider.be> wrote:
> > > Use the new devm_of_phy_optional_get() helper instead of open-coding the
> > > same operation.
> > >
> > > This lets us drop several checks for IS_ERR(), as phy_power_{on,off}()
> > > handle NULL parameters fine.
> > >
> > > Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
> > > ---
> > >  drivers/usb/host/ohci-exynos.c | 24 +++++++-----------------
> > >  1 file changed, 7 insertions(+), 17 deletions(-)
> > >
> > > diff --git a/drivers/usb/host/ohci-exynos.c b/drivers/usb/host/ohci-exynos.c
> > > index 8d7977fd5d3bd502..8dd9c3b2411c383f 100644
> > > --- a/drivers/usb/host/ohci-exynos.c
> > > +++ b/drivers/usb/host/ohci-exynos.c
> > > @@ -69,19 +69,12 @@ static int exynos_ohci_get_phy(struct device *dev,
> > >                         return -EINVAL;
> > >                 }
> > >
> > > -               phy = devm_of_phy_get(dev, child, NULL);
> > > +               phy = devm_of_phy_optional_get(dev, child, NULL);
> > >                 exynos_ohci->phy[phy_number] = phy;
> > >                 if (IS_ERR(phy)) {
> > > -                       ret = PTR_ERR(phy);
> > > -                       if (ret == -EPROBE_DEFER) {
> > > -                               of_node_put(child);
> > > -                               return ret;
> > > -                       } else if (ret != -ENOSYS && ret != -ENODEV) {
> > > -                               dev_err(dev,
> > > -                                       "Error retrieving usb2 phy: %d\n", ret);
> > > -                               of_node_put(child);
> > > -                               return ret;
> > > -                       }
> > > +                       of_node_put(child);
> > > +                       return dev_err_probe(dev, PTR_ERR(phy),
> > > +                                            "Error retrieving usb2 phy\n");
> >
> > Optional is really the only reason for the caller to decide whether to
> > print an error message or not. If we have both flavors of 'get', then
> > really the 'get' functions should print an error message.
>
> In case of a real error, both should print an error message, right?
>
> Anyway, I understand that's a three step operation:
>   1. Introduce and convert to the _optional variant,
>   2. Add error printing to callees.
>   3. Remove error printing from callers.

I think you only need 2 out of 3 steps depending on the situation. In
this case, you can add error printing in the _optional variant when
you introduce it and then convert callers to it.

Where we already have an optional variant, then you need steps 2 and 3.

Rob