linux-kernel - Re: [PATCH v8 3/6] pwm: sun4i: Add an optional probe for bus clock

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Message-ID: <CAJiuCcfj7rngTgbZQDwjKoLgRGcqsYscBvrCP095zzyASKSqdQ@mail.gmail.com>
Date:   Thu, 21 Nov 2019 22:31:31 +0100
From:   Clément Péron <peron.clem@...il.com>
To:     Uwe Kleine-König 
        <u.kleine-koenig@...gutronix.de>
Cc:     Thierry Reding <thierry.reding@...il.com>,
        Maxime Ripard <mripard@...nel.org>,
        Chen-Yu Tsai <wens@...e.org>,
        Philipp Zabel <pza@...gutronix.de>, linux-pwm@...r.kernel.org,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        linux-sunxi <linux-sunxi@...glegroups.com>,
        Jernej Skrabec <jernej.skrabec@...l.net>
Subject: Re: [PATCH v8 3/6] pwm: sun4i: Add an optional probe for bus clock

Hi Uwe,

On Thu, 21 Nov 2019 at 22:06, Uwe Kleine-König
<u.kleine-koenig@...gutronix.de> wrote:
>
> On Thu, Nov 21, 2019 at 08:58:59PM +0100, Clément Péron wrote:
> > From: Jernej Skrabec <jernej.skrabec@...l.net>
> >
> > H6 PWM core needs bus clock to be enabled in order to work.
> >
> > Add an optional probe for it.
> >
> > Signed-off-by: Jernej Skrabec <jernej.skrabec@...l.net>
> > Signed-off-by: Clément Péron <peron.clem@...il.com>
> > ---
> >  drivers/pwm/pwm-sun4i.c | 23 +++++++++++++++++++++++
> >  1 file changed, 23 insertions(+)
> >
> > diff --git a/drivers/pwm/pwm-sun4i.c b/drivers/pwm/pwm-sun4i.c
> > index 369990ae7d09..66befd8d6f9c 100644
> > --- a/drivers/pwm/pwm-sun4i.c
> > +++ b/drivers/pwm/pwm-sun4i.c
> > @@ -78,6 +78,7 @@ struct sun4i_pwm_data {
> >
> >  struct sun4i_pwm_chip {
> >       struct pwm_chip chip;
> > +     struct clk *bus_clk;
> >       struct clk *clk;
> >       struct reset_control *rst;
> >       void __iomem *base;
> > @@ -391,6 +392,14 @@ static int sun4i_pwm_probe(struct platform_device *pdev)
> >               }
> >       }
> >
> > +     pwm->bus_clk = devm_clk_get_optional(&pdev->dev, "bus");
> > +     if (IS_ERR(pwm->bus_clk)) {
> > +             if (PTR_ERR(pwm->rst) != -EPROBE_DEFER)
> > +                     dev_err(&pdev->dev, "get bus clock failed %pe\n",
> > +                             pwm->bus_clk);
> > +             return PTR_ERR(pwm->bus_clk);
> > +     }
> > +
> >       pwm->rst = devm_reset_control_get_optional_shared(&pdev->dev, NULL);
> >       if (IS_ERR(pwm->rst)) {
> >               if (PTR_ERR(pwm->rst) != -EPROBE_DEFER)
> > @@ -407,6 +416,17 @@ static int sun4i_pwm_probe(struct platform_device *pdev)
> >               return ret;
> >       }
> >
> > +     /*
> > +      * We're keeping the bus clock on for the sake of simplicity.
> > +      * Actually it only needs to be on for hardware register accesses.
> > +      */
> > +     ret = clk_prepare_enable(pwm->bus_clk);
> > +     if (ret) {
> > +             dev_err(&pdev->dev, "Cannot prepare and enable bus_clk %d\n",
> > +                     ret);
>
> nitpick: other error messages in this driver start with a lower case
> letter.
>
> Until there is an equivalent for %pe that consumes an int, I suggest to
> use
>
>         dev_err(&pdev->dev, "Cannot prepare and enable bus_clk: %pe\n",
>                 ERR_PTR(ret));
>
> to benefit from a symbolic error name instead of an error constant.

Ok i will fix both

Thanks,
Clement

>
> Best regards
> Uwe
>
> --
> Pengutronix e.K.                           | Uwe Kleine-König            |
> Industrial Linux Solutions                 | https://www.pengutronix.de/ |