linux-kernel - Re: [PATCH v3 01/11] firmware: raspberrypi: Introduce devm_rpi_firmware

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Message-ID: <47eaba0bc71c6e23bff87b8a01cebf0c6d12efd0.camel@suse.de>
Date:   Thu, 05 Nov 2020 10:28:38 +0100
From:   Nicolas Saenz Julienne <nsaenzjulienne@...e.de>
To:     Bartosz Golaszewski <bgolaszewski@...libre.com>
Cc:     Uwe Kleine-König 
        <u.kleine-koenig@...gutronix.de>,
        LKML <linux-kernel@...r.kernel.org>,
        Florian Fainelli <f.fainelli@...il.com>,
        Ray Jui <rjui@...adcom.com>,
        Scott Branden <sbranden@...adcom.com>,
        bcm-kernel-feedback-list@...adcom.com, linux-pwm@...r.kernel.org,
        arm-soc <linux-arm-kernel@...ts.infradead.org>,
        linux-devicetree <devicetree@...r.kernel.org>, wahrenst@....net,
        Linux Input <linux-input@...r.kernel.org>,
        Dmitry Torokhov <dmitry.torokhov@...il.com>,
        Greg KH <gregkh@...uxfoundation.org>,
        devel@...verdev.osuosl.org, Philipp Zabel <p.zabel@...gutronix.de>,
        linux-gpio <linux-gpio@...r.kernel.org>,
        Linus Walleij <linus.walleij@...aro.org>,
        linux-clk <linux-clk@...r.kernel.org>,
        Stephen Boyd <sboyd@...nel.org>,
        linux-rpi-kernel@...ts.infradead.org,
        Andy Shevchenko <andy.shevchenko@...il.com>
Subject: Re: [PATCH v3 01/11] firmware: raspberrypi: Introduce
 devm_rpi_firmware_get()

Hi Bartosz, thanks for the review.

On Thu, 2020-11-05 at 10:13 +0100, Bartosz Golaszewski wrote:
> > +/**
> > + * devm_rpi_firmware_get - Get pointer to rpi_firmware structure.
> > + * @firmware_node:    Pointer to the firmware Device Tree node.
> > + *
> > + * Returns NULL is the firmware device is not ready.
> > + */
> > +struct rpi_firmware *devm_rpi_firmware_get(struct device *dev,
> > +                                          struct device_node *firmware_node)
> > +{
> > +       struct platform_device *pdev = of_find_device_by_node(firmware_node);
> > +       struct rpi_firmware *fw;
> > +
> > +       if (!pdev)
> > +               return NULL;
> > +
> > +       fw = platform_get_drvdata(pdev);
> > +       if (!fw)
> > +               return NULL;
> > +
> > +       if (!refcount_inc_not_zero(&fw->consumers))
> > +               return NULL;
> > +
> > +       if (devm_add_action_or_reset(dev, rpi_firmware_put, fw))
> > +               return NULL;
> > +
> > +       return fw;
> > +}
> > +EXPORT_SYMBOL_GPL(devm_rpi_firmware_get);
> 
> Usually I'd expect the devres variant to simply call
> rpi_firmware_get() and then schedule a release callback which would
> call whatever function is the release counterpart for it currently.
> Devres actions are for drivers which want to schedule some more
> unusual tasks at driver detach. Any reason for designing it this way?

Yes, see patch #8 where I get rid of rpi_firmware_get() altogether after
converting all users to devres. Since there is no use for the vanilla version
of the function anymore, I figured it'd be better to merge everything into
devm_rpi_firmware_get(). That said it's not something I have strong feelings
about.

Regards,
Nicolas


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