linux-kernel - Re: [PATCH 10/14] phy: meson8b-usb2: simplify optional reset handling

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Date:   Wed, 15 Feb 2017 17:43:27 +0100
From:   Jerome Brunet <jbrunet@...libre.com>
To:     Martin Blumenstingl <martin.blumenstingl@...glemail.com>,
        Philipp Zabel <p.zabel@...gutronix.de>
Cc:     linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        Ramiro Oliveira <Ramiro.Oliveira@...opsys.com>,
        Kevin Hilman <khilman@...libre.com>,
        Carlo Caione <carlo@...one.org>,
        Kishon Vijay Abraham I <kishon@...com>
Subject: Re: [PATCH 10/14] phy: meson8b-usb2: simplify optional reset
 handling

On Wed, 2017-02-15 at 00:36 +0100, Martin Blumenstingl wrote:
> Hi Philipp,
> 
> sorry for the late reply.
> unfortunately my GXBB board (which is supported by the driver below)
> is dead.
> I CC'ed Jerome Brunet - maybe he can give it a go on one of his
> (GXBB) boards.
> 
> On Mon, Jan 30, 2017 at 12:41 PM, Philipp Zabel <p.zabel@...gutronix.
> de> wrote:
> > 
> > As of commit bb475230b8e5 ("reset: make optional functions really
> > optional"), the reset framework API calls use NULL pointers to
> > describe
> > optional, non-present reset controls.
> > 
> > This allows to return errors from
> > devm_reset_control_get_optional_shared
> > and to call reset_control_reset unconditionally.
> > 
> > Signed-off-by: Philipp Zabel <p.zabel@...gutronix.de>
> Acked-by: Martin Blumenstingl <martin.blumenstingl@...glemail.com>
> 
> (based on reading the code along with the highly appreciated changes
> from bb475230b8e5)
> 
> > 
> > Cc: Martin Blumenstingl <martin.blumenstingl@...glemail.com>
> > Cc: Kevin Hilman <khilman@...libre.com>
> > Cc: Carlo Caione <carlo@...one.org>
> > Cc: Kishon Vijay Abraham I <kishon@...com>
> > ---
> >  drivers/phy/phy-meson8b-usb2.c | 12 +++++-------
> >  1 file changed, 5 insertions(+), 7 deletions(-)
> > 
> > diff --git a/drivers/phy/phy-meson8b-usb2.c b/drivers/phy/phy-
> > meson8b-usb2.c
> > index 33c9f4ba157d1..87168f1fe3af6 100644
> > --- a/drivers/phy/phy-meson8b-usb2.c
> > +++ b/drivers/phy/phy-meson8b-usb2.c
> > @@ -141,12 +141,10 @@ static int phy_meson8b_usb2_power_on(struct
> > phy *phy)
> >         struct phy_meson8b_usb2_priv *priv = phy_get_drvdata(phy);
> >         int ret;
> > 
> > -       if (!IS_ERR_OR_NULL(priv->reset)) {
> > -               ret = reset_control_reset(priv->reset);
> > -               if (ret) {
> > -                       dev_err(&phy->dev, "Failed to trigger USB
> > reset\n");
> > -                       return ret;
> > -               }
> > +       ret = reset_control_reset(priv->reset);
> > +       if (ret) {
> > +               dev_err(&phy->dev, "Failed to trigger USB
> > reset\n");
> > +               return ret;
> >         }
> > 
> >         ret = clk_prepare_enable(priv->clk_usb_general);
> > @@ -241,7 +239,7 @@ static int phy_meson8b_usb2_probe(struct
> > platform_device *pdev)
> >                 return PTR_ERR(priv->clk_usb);
> > 
> >         priv->reset = devm_reset_control_get_optional_shared(&pdev-
> > >dev, NULL);
> > -       if (PTR_ERR(priv->reset) == -EPROBE_DEFER)
> > +       if (PTR_ERR(priv->reset))

This is wrong and will always exit on error. It should be "IS_ERR".
Clearly the bug was there before your patch, but since you are changing
the faulty line, would you mind using IS_ERR instead ?

With this changed:
Tested-by: Jerome Brunet <jbrunet@...libre.com>

> >                 return PTR_ERR(priv->reset);
> > 
> >         priv->dr_mode = of_usb_get_dr_mode_by_phy(pdev-
> > >dev.of_node, -1);
> > --
> > 2.11.0
> >