linux-kernel - Re: [PATCH v4] PM / devfreq: exynos: Use Use devm_clk_get

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Date: Fri, 10 May 2024 14:09:03 +0530
From: Anand Moon <linux.amoon@...il.com>
To: Christophe JAILLET <christophe.jaillet@...adoo.fr>
Cc: Chanwoo Choi <cw00.choi@...sung.com>, MyungJoo Ham <myungjoo.ham@...sung.com>, 
	Kyungmin Park <kyungmin.park@...sung.com>, Krzysztof Kozlowski <krzk@...nel.org>, 
	Alim Akhtar <alim.akhtar@...sung.com>, linux-pm@...r.kernel.org, 
	linux-samsung-soc@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4] PM / devfreq: exynos: Use Use devm_clk_get_enabled() helpers

Hi Christophe,

On Fri, 10 May 2024 at 01:35, Christophe JAILLET
<christophe.jaillet@...adoo.fr> wrote:
>
> Le 09/05/2024 à 08:47, Anand Moon a écrit :
> > The devm_clk_get_enabled() helpers:
> >      - call devm_clk_get()
> >      - call clk_prepare_enable() and register what is needed in order to
> >       call clk_disable_unprepare() when needed, as a managed resource.
> >
> > This simplifies the code and avoids the calls to clk_disable_unprepare().
> >
> > While at it, use dev_err_probe consistently, and use its return value
> > to return the error code.
> >
> > Signed-off-by: Anand Moon <linux.amoon@...il.com>
> > ---
> > V4 - wrap up the error messagee within 80 char
> > v3 - No change
> > v2 - No change
> > ---
> >   drivers/devfreq/exynos-bus.c | 22 +++++-----------------
> >   1 file changed, 5 insertions(+), 17 deletions(-)
> >
> > diff --git a/drivers/devfreq/exynos-bus.c b/drivers/devfreq/exynos-bus.c
> > index 00118580905a..7d06c476d8e9 100644
> > --- a/drivers/devfreq/exynos-bus.c
> > +++ b/drivers/devfreq/exynos-bus.c
> > @@ -160,7 +160,6 @@ static void exynos_bus_exit(struct device *dev)
> >       platform_device_unregister(bus->icc_pdev);
> >
> >       dev_pm_opp_of_remove_table(dev);
> > -     clk_disable_unprepare(bus->clk);
> >       dev_pm_opp_put_regulators(bus->opp_token);
> >   }
> >
> > @@ -171,7 +170,6 @@ static void exynos_bus_passive_exit(struct device *dev)
> >       platform_device_unregister(bus->icc_pdev);
> >
> >       dev_pm_opp_of_remove_table(dev);
> > -     clk_disable_unprepare(bus->clk);
> >   }
> >
> >   static int exynos_bus_parent_parse_of(struct device_node *np,
> > @@ -247,23 +245,16 @@ static int exynos_bus_parse_of(struct device_node *np,
> >       int ret;
> >
> >       /* Get the clock to provide each bus with source clock */
> > -     bus->clk = devm_clk_get(dev, "bus");
> > -     if (IS_ERR(bus->clk)) {
> > -             dev_err(dev, "failed to get bus clock\n");
> > -             return PTR_ERR(bus->clk);
> > -     }
> > -
> > -     ret = clk_prepare_enable(bus->clk);
> > -     if (ret < 0) {
> > -             dev_err(dev, "failed to get enable clock\n");
> > -             return ret;
> > -     }
> > +     bus->clk = devm_clk_get_enabled(dev, "bus");
> > +     if (IS_ERR(bus->clk))
> > +             return dev_err_probe(dev, PTR_ERR(bus->clk),
> > +                             "failed to get bus clock\n");
> >
> >       /* Get the freq and voltage from the OPP table to scale the bus freq */
> >       ret = dev_pm_opp_of_add_table(dev);
> >       if (ret < 0) {
> >               dev_err(dev, "failed to get OPP table\n");
> > -             goto err_clk;
> > +             return ret;
> >       }
> >
> >       rate = clk_get_rate(bus->clk);
> > @@ -281,8 +272,6 @@ static int exynos_bus_parse_of(struct device_node *np,
> >
> >   err_opp:
> >       dev_pm_opp_of_remove_table(dev);
> > -err_clk:
> > -     clk_disable_unprepare(bus->clk);
> >
> >       return ret;
> >   }
> > @@ -453,7 +442,6 @@ static int exynos_bus_probe(struct platform_device *pdev)
> >
> >   err:
> >       dev_pm_opp_of_remove_table(dev);
> > -     clk_disable_unprepare(bus->clk);
> >   err_reg:
> >       dev_pm_opp_put_regulators(bus->opp_token);
> >
>
> Hi,
>
> If the patch is correct, I think that clk in struct exynos_bus can be
> easily be removed as well.
>

Yes, you are correct, I will submit a patch following these changes.

> CJ

Thanks
-Anand