linux-kernel - Re: [PATCH v3 1/3] memory: tegra: Add devm_tegra_get_memory

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Date:   Wed, 30 Sep 2020 12:27:15 +0200
From:   Krzysztof Kozlowski <krzk@...nel.org>
To:     Nicolin Chen <nicoleotsuka@...il.com>
Cc:     thierry.reding@...il.com, joro@...tes.org, digetx@...il.com,
        vdumpa@...dia.com, jonathanh@...dia.com,
        linux-tegra@...r.kernel.org, iommu@...ts.linux-foundation.org,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v3 1/3] memory: tegra: Add
 devm_tegra_get_memory_controller()

On Wed, Sep 30, 2020 at 02:41:45AM -0700, Nicolin Chen wrote:
> On Wed, Sep 30, 2020 at 11:07:32AM +0200, Krzysztof Kozlowski wrote:
> > "On Wed, 30 Sep 2020 at 10:48, Nicolin Chen <nicoleotsuka@...il.com> wrote:
> > >
> > > From: Dmitry Osipenko <digetx@...il.com>
> > >
> > > Multiple Tegra drivers need to retrieve Memory Controller and hence there
> > > is quite some duplication of the retrieval code among the drivers. Let's
> > > add a new common helper for the retrieval of the MC.
> > >
> > > Signed-off-by: Dmitry Osipenko <digetx@...il.com>
> > > Signed-off-by: Nicolin Chen <nicoleotsuka@...il.com>
> > > ---
> > >
> > > Changelog
> > > v2->v3:
> > >  * Replaced with Dimtry's devm_tegra_get_memory_controller()
> > > v1->v2:
> > >  * N/A
> > >
> > >  drivers/memory/tegra/mc.c | 39 +++++++++++++++++++++++++++++++++++++++
> > >  include/soc/tegra/mc.h    | 17 +++++++++++++++++
> > >  2 files changed, 56 insertions(+)
> > >
> > > diff --git a/drivers/memory/tegra/mc.c b/drivers/memory/tegra/mc.c
> > > index ec8403557ed4..dd691dc3738e 100644
> > > --- a/drivers/memory/tegra/mc.c
> > > +++ b/drivers/memory/tegra/mc.c
> > > @@ -42,6 +42,45 @@ static const struct of_device_id tegra_mc_of_match[] = {
> > >  };
> > >  MODULE_DEVICE_TABLE(of, tegra_mc_of_match);
> > >
> > > +static void tegra_mc_devm_action_put_device(void *data)
> > 
> > devm_tegra_memory_controller_put()

My bad here, this is not a "put" helper so the previous name was
actually good. No need to change.

> > 
> > > +{
> > > +       struct tegra_mc *mc = data;
> > > +
> > > +       put_device(mc->dev);
> > > +}
> > > +
> > > +struct tegra_mc *devm_tegra_get_memory_controller(struct device *dev)
> > 
> > Usually 'get' is a suffix (e.g. clk, gpiod, iio, led), so:
> > devm_tegra_memory_controller_get()
> > 
> > > +{
> > > +       struct platform_device *pdev;
> > > +       struct device_node *np;
> > > +       struct tegra_mc *mc;
> > > +       int err;
> > > +
> > > +       np = of_find_matching_node_and_match(NULL, tegra_mc_of_match, NULL);
> > > +       if (!np)
> > > +               return ERR_PTR(-ENOENT);
> > > +
> > > +       pdev = of_find_device_by_node(np);
> > > +       of_node_put(np);
> > > +       if (!pdev)
> > > +               return ERR_PTR(-ENODEV);
> > > +
> > > +       mc = platform_get_drvdata(pdev);
> > > +       if (!mc) {
> > > +               put_device(mc->dev);
> > > +               return ERR_PTR(-EPROBE_DEFER);
> > > +       }
> > > +
> > > +       err = devm_add_action(dev, tegra_mc_devm_action_put_device, mc);

This can be simpler with devm_add_action_or_reset.

Best regards,
Krzysztof