netdev - Re: [PATCH 7/7] usb: host: ohci-exynos: Convert to devm_of_phy_optional

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Date:   Fri, 20 Jan 2023 08:56:29 +0100
From:   Geert Uytterhoeven <geert@...ux-m68k.org>
To:     Rob Herring <robh@...nel.org>, Vinod Koul <vkoul@...nel.org>
Cc:     Madalin Bucur <madalin.bucur@....com>,
        "David S . Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        Horatiu Vultur <horatiu.vultur@...rochip.com>,
        UNGLinuxDriver@...rochip.com,
        Thierry Reding <thierry.reding@...il.com>,
        Lorenzo Pieralisi <lpieralisi@...nel.org>,
        Krzysztof Wilczyński <kw@...ux.com>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Jonathan Hunter <jonathanh@...dia.com>,
        Kishon Vijay Abraham I <kishon@...nel.org>,
        Alan Stern <stern@...land.harvard.edu>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
        Alim Akhtar <alim.akhtar@...sung.com>,
        Siddharth Vadapalli <s-vadapalli@...com>,
        Russell King <linux@...linux.org.uk>, netdev@...r.kernel.org,
        linux-tegra@...r.kernel.org, linux-pci@...r.kernel.org,
        linux-phy@...ts.infradead.org, linux-usb@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-samsung-soc@...r.kernel.org
Subject: Re: [PATCH 7/7] usb: host: ohci-exynos: Convert to devm_of_phy_optional_get()

Hi Rob,

On Wed, Jan 18, 2023 at 8:49 PM Rob Herring <robh@...nel.org> wrote:
> On Wed, Jan 18, 2023 at 12:28 PM Geert Uytterhoeven
> <geert@...ux-m68k.org> wrote:
> > On Wed, Jan 18, 2023 at 6:30 PM Rob Herring <robh@...nel.org> wrote:
> > > On Wed, Jan 18, 2023 at 4:15 AM Geert Uytterhoeven
> > > <geert+renesas@...der.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@...der.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.

Right, so the error printing can be done now, while introducing
devm_of_phy_optional_get().

Vinod: Do you agree?
If yes, I can respin with that change.
If not, I'll have to respin anyway, as the bug in
am65_cpsw_init_serdes_phy() has been fixed in the meantime.

Thanks!

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds