linux-kernel - Re: [PATCH 12/12] of/platform: make the OF code aware of early platform drivers

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Date:   Mon, 14 May 2018 23:32:02 +0200
From:   Geert Uytterhoeven <geert@...ux-m68k.org>
To:     Bartosz Golaszewski <brgl@...ev.pl>
Cc:     Sekhar Nori <nsekhar@...com>, Kevin Hilman <khilman@...nel.org>,
        David Lechner <david@...hnology.com>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>, Arnd Bergmann <arnd@...db.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Mark Rutland <mark.rutland@....com>,
        Yoshinori Sato <ysato@...rs.sourceforge.jp>,
        Rich Felker <dalias@...c.org>,
        Andy Shevchenko <andy.shevchenko@...il.com>,
        Marc Zyngier <marc.zyngier@....com>,
        "Rafael J . Wysocki" <rafael.j.wysocki@...el.com>,
        Peter Rosin <peda@...ntia.se>, Jiri Slaby <jslaby@...e.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        Magnus Damm <magnus.damm@...il.com>,
        Johan Hovold <johan@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Frank Rowand <frowand.list@...il.com>,
        Linux ARM <linux-arm-kernel@...ts.infradead.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@...r.kernel.org>,
        Linux-Arch <linux-arch@...r.kernel.org>,
        Bartosz Golaszewski <bgolaszewski@...libre.com>
Subject: Re: [PATCH 12/12] of/platform: make the OF code aware of early
 platform drivers

Hi Bartosz,

On Fri, May 11, 2018 at 6:20 PM, Bartosz Golaszewski <brgl@...ev.pl> wrote:
> From: Bartosz Golaszewski <bgolaszewski@...libre.com>
>
> Check the relevant flag in the device node and skip the allocation
> part for devices that were populated early.
>
> Signed-off-by: Bartosz Golaszewski <bgolaszewski@...libre.com>

Thanks for your patch!

> --- a/drivers/of/platform.c
> +++ b/drivers/of/platform.c

> @@ -196,9 +197,17 @@ static struct platform_device *of_platform_device_create_pdata(
>             of_node_test_and_set_flag(np, OF_POPULATED))
>                 return NULL;
>
> -       dev = of_device_alloc(np, bus_id, parent);
> -       if (!dev)
> -               goto err_clear_flag;
> +       if (of_node_check_flag(np, OF_POPULATED_EARLY)) {
> +               dev = of_early_to_platform_device(np);
> +               if (IS_ERR(dev))
> +                       goto err_clear_flag;
> +
> +               of_device_init(dev, np, bus_id, parent);
> +       } else {
> +               dev = of_device_alloc(np, bus_id, parent);
> +               if (!dev)
> +                       goto err_clear_flag;
> +       }

The above may become cleaner if:
  1. of_early_to_platform_device() would return NULL instead -ENOENT,
  2. of_device_alloc() would be split in alloc and init phases, too.

Then you can do:

        dev = of_node_check_flag(np, OF_POPULATED_EARLY)
                ? of_early_to_platform_device(np)
                 : __of_device_alloc(np, bus_id, parent);
        if (!dev)
                goto err_clear_flag;

        of_device_init(dev, np, bus_id, parent);

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