linux-kernel - Re: [PATCH v2 04/11] gpiolib: Clear the gpio_device's fwnode initialized flag before adding

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Date:   Fri, 27 Jan 2023 23:33:38 -0800
From:   Saravana Kannan <saravanak@...gle.com>
To:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Sudeep Holla <sudeep.holla@....com>,
        Cristian Marussi <cristian.marussi@....com>,
        Linus Walleij <linus.walleij@...aro.org>,
        Bartosz Golaszewski <brgl@...ev.pl>,
        Thomas Gleixner <tglx@...utronix.de>,
        Marc Zyngier <maz@...nel.org>, Shawn Guo <shawnguo@...nel.org>,
        Sascha Hauer <s.hauer@...gutronix.de>,
        Pengutronix Kernel Team <kernel@...gutronix.de>,
        Fabio Estevam <festevam@...il.com>,
        NXP Linux Team <linux-imx@....com>,
        Rob Herring <robh+dt@...nel.org>,
        Frank Rowand <frowand.list@...il.com>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        Magnus Damm <magnus.damm@...il.com>,
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        Daniel Scally <djrscally@...il.com>,
        Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
        Sakari Ailus <sakari.ailus@...ux.intel.com>,
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        Linux Kernel Functional Testing <lkft@...aro.org>,
        Naresh Kamboju <naresh.kamboju@...aro.org>,
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        Jean-Philippe Brucker <jpb@...nel.org>,
        kernel-team@...roid.com, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-gpio@...r.kernel.org,
        devicetree@...r.kernel.org, linux-renesas-soc@...r.kernel.org,
        linux-acpi@...r.kernel.org
Subject: Re: [PATCH v2 04/11] gpiolib: Clear the gpio_device's fwnode
 initialized flag before adding

On Fri, Jan 27, 2023 at 1:27 AM Andy Shevchenko
<andriy.shevchenko@...ux.intel.com> wrote:
>
> On Thu, Jan 26, 2023 at 04:11:31PM -0800, Saravana Kannan wrote:
> > Registering an irqdomain sets the flag for the fwnode. But having the
> > flag set when a device is added is interpreted by fw_devlink to mean the
> > device has already been initialized and will never probe. This prevents
> > fw_devlink from creating device links with the gpio_device as a
> > supplier. So, clear the flag before adding the device.
>
> ...
>
> > +     /*
> > +      * If fwnode doesn't belong to another device, it's safe to clear its
> > +      * initialized flag.
> > +      */
> > +     if (!gdev->dev.fwnode->dev)
> > +             fwnode_dev_initialized(gdev->dev.fwnode, false);
>
> Do not dereference fwnode in struct device. Use dev_fwnode() for that.
>
>         struct fwnode_handle *fwnode = dev_fwnode(&gdev->dev);
>
>         if (!fwnode->dev)
>                 fwnode_dev_initialized(fwnode, false);

Honestly, we should work towards NOT needing dev_fwnode(). The
function literally dereferences dev->fwnode or the one inside of_node.
So my dereference is fine. The whole "fwnode might not be set for
devices with of_node" is wrong and we should fix that instead of
writing wrappers to work around it.

Also, for now I'm going to leave this as if for the same reasons as I
mentioned in Patch 1.

>
> + Blank line.

Ack.


-Saravana

>
> >       ret = gcdev_register(gdev, gpio_devt);
> >       if (ret)
> >               return ret;
>
> --
> With Best Regards,
> Andy Shevchenko
>
>
> --
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