linux-kernel - Re: [PATCH v2 2/2] i2c: mark device nodes only in case of successful instantiation

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Date:   Mon, 17 Oct 2016 16:16:45 +0200
From:   Geert Uytterhoeven <geert@...ux-m68k.org>
To:     Ralf Ramsauer <ralf@...ses-pyramidenbau.de>
Cc:     Mark Brown <broonie@...nel.org>, Wolfram Sang <wsa@...-dreams.de>,
        Linux SPI <linux-spi@...r.kernel.org>,
        Linux I2C <linux-i2c@...r.kernel.org>,
        "linux-kernel @ vger . kernel . org" <linux-kernel@...r.kernel.org>,
        Pantelis Antoniou <pantelis.antoniou@...sulko.com>
Subject: Re: [PATCH v2 2/2] i2c: mark device nodes only in case of successful instantiation

On Mon, Oct 17, 2016 at 3:59 PM, Ralf Ramsauer
<ralf@...ses-pyramidenbau.de> wrote:
> Instantiated I2C device nodes are marked with OF_POPULATE. This was
> introduced in 4f001fd. On unloading, loaded device nodes will of course
> be unmarked. The problem are nodes that fail during initialisation: If a
> node fails, it won't be unloaded and hence not be unmarked.
>
> If a I2C driver module is unloaded and reloaded, it will skip nodes that
> failed before.
>
> Skip device nodes that are already populated and mark them only in case
> of success.
>
> Note that the same issue exists for SPI.
>
> Fixes: 4f001fd ("i2c: Mark instantiated device nodes with OF_POPULATE")
> Signed-off-by: Ralf Ramsauer <ralf@...ses-pyramidenbau.de>

Reviewed-by: Geert Uytterhoeven <geert+renesas@...der.be>

> --- a/drivers/i2c/i2c-core.c
> +++ b/drivers/i2c/i2c-core.c

> @@ -1695,7 +1696,14 @@ static void of_i2c_register_devices(struct i2c_adapter *adap)
>         for_each_available_child_of_node(bus, node) {
>                 if (of_node_test_and_set_flag(node, OF_POPULATED))
>                         continue;
> -               of_i2c_register_device(adap, node);
> +
> +               client = of_i2c_register_device(adap, node);
> +               if (IS_ERR(client)) {
> +                       dev_warn(&adap->dev,
> +                                "Failed to create I2C device for %s\n",
> +                                node->full_name);

I don't think there's a need to add this warning, as of_i2c_register_device()
already prints messages in all failure paths.

> +                       of_node_clear_flag(node, OF_POPULATED);
> +               }
>         }

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