linux-kernel - Re: [PATCH net-next v3 04/12] net: pcs: add Renesas MII converter driver

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Date:   Thu, 5 May 2022 15:00:28 +0200
From:   Geert Uytterhoeven <geert@...ux-m68k.org>
To:     Clément Léger <clement.leger@...tlin.com>
Cc:     Andrew Lunn <andrew@...n.ch>,
        Vivien Didelot <vivien.didelot@...il.com>,
        Florian Fainelli <f.fainelli@...il.com>,
        Vladimir Oltean <olteanv@...il.com>,
        "David S . Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        Magnus Damm <magnus.damm@...il.com>,
        Heiner Kallweit <hkallweit1@...il.com>,
        Russell King <linux@...linux.org.uk>,
        Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
        Herve Codina <herve.codina@...tlin.com>,
        Miquèl Raynal <miquel.raynal@...tlin.com>,
        Milan Stevanovic <milan.stevanovic@...com>,
        Jimmy Lalande <jimmy.lalande@...com>,
        Pascal Eberhard <pascal.eberhard@...com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@...r.kernel.org>,
        Linux-Renesas <linux-renesas-soc@...r.kernel.org>,
        netdev <netdev@...r.kernel.org>
Subject: Re: [PATCH net-next v3 04/12] net: pcs: add Renesas MII converter driver

Hi Clément,

On Thu, May 5, 2022 at 2:33 PM Clément Léger <clement.leger@...tlin.com> wrote:
> Le Thu, 5 May 2022 09:16:38 +0200,
> Geert Uytterhoeven <geert@...ux-m68k.org> a écrit :
> > On Wed, May 4, 2022 at 11:31 AM Clément Léger <clement.leger@...tlin.com> wrote:
> > > Add a PCS driver for the MII converter that is present on the Renesas
> > > RZ/N1 SoC. This MII converter is reponsible for converting MII to
> > > RMII/RGMII or act as a MII pass-trough. Exposing it as a PCS allows to
> > > reuse it in both the switch driver and the stmmac driver. Currently,
> > > this driver only allows the PCS to be used by the dual Cortex-A7
> > > subsystem since the register locking system is not used.
> > >
> > > Signed-off-by: Clément Léger <clement.leger@...tlin.com>
> >
> > Thanks for your patch!
> >
> > > --- /dev/null
> > > +++ b/drivers/net/pcs/pcs-rzn1-miic.c
> >
> > > +static int miic_probe(struct platform_device *pdev)
> > > +{
> > > +       struct device *dev = &pdev->dev;
> > > +       struct miic *miic;
> > > +       u32 mode_cfg;
> > > +       int ret;
> > > +
> > > +       ret = miic_parse_dt(dev, &mode_cfg);
> > > +       if (ret < 0)
> > > +               return -EINVAL;
> > > +
> > > +       miic = devm_kzalloc(dev, sizeof(*miic), GFP_KERNEL);
> > > +       if (!miic)
> > > +               return -ENOMEM;
> > > +
> > > +       spin_lock_init(&miic->lock);
> > > +       miic->dev = dev;
> > > +       miic->base = devm_platform_ioremap_resource(pdev, 0);
> > > +       if (!miic->base)
> > > +               return -EINVAL;
> > > +
> > > +       pm_runtime_enable(dev);
> > > +       ret = pm_runtime_resume_and_get(dev);
> > > +       if (ret < 0)
> >
> > Missing pm_runtime_disable(dev).
>
> Maybe using devm_pm_runtime_enable() would be sufficient and avoid such
> calls.

That's an option.
Note that that still won't allow you to get rid of the .remove() callback,
as you still have to call pm_runtime_put() manually.

> >
> > > +               return ret;
> > > +
> > > +       ret = miic_init_hw(miic, mode_cfg);
> > > +       if (ret)
> > > +               goto disable_runtime_pm;
> > > +
> > > +       /* miic_create() relies on that fact that data are attached to the
> > > +        * platform device to determine if the driver is ready so this needs to
> > > +        * be the last thing to be done after everything is initialized
> > > +        * properly.
> > > +        */
> > > +       platform_set_drvdata(pdev, miic);
> > > +
> > > +       return 0;
> > > +
> > > +disable_runtime_pm:
> > > +       pm_runtime_put(dev);
> >
> > Missing pm_runtime_disable(dev).
> >
> > > +
> > > +       return ret;
> > > +}
> > > +
> > > +static int miic_remove(struct platform_device *pdev)
> > > +{
> > > +       pm_runtime_put(&pdev->dev);
> >
> > Missing pm_runtime_disable(dev).

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