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References: <20231128084236.157152-1-wenst@chromium.org> <20231128084236.157152-4-wenst@chromium.org>
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From:   Doug Anderson <dianders@chromium.org>
Date:   Fri, 1 Dec 2023 16:58:20 -0800
Message-ID: <CAD=FV=XV0+G=uFBE_n6WFGVW2szGcKToZgCNTdSrNf3LVk9MOQ@mail.gmail.com>
Subject: Re: [RFC PATCH v3 3/5] platform/chrome: Introduce device tree
 hardware prober
To:     Chen-Yu Tsai <wenst@chromium.org>
Cc:     Rob Herring <robh+dt@kernel.org>,
        Frank Rowand <frowand.list@gmail.com>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Conor Dooley <conor+dt@kernel.org>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@collabora.com>,
        Wolfram Sang <wsa@kernel.org>,
        Benson Leung <bleung@chromium.org>,
        Tzung-Bi Shih <tzungbi@kernel.org>,
        chrome-platform@lists.linux.dev, devicetree@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org,
        linux-mediatek@lists.infradead.org, linux-kernel@vger.kernel.org,
        Johan Hovold <johan@kernel.org>,
        Hsin-Yi Wang <hsinyi@chromium.org>,
        Dmitry Torokhov <dmitry.torokhov@gmail.com>,
        andriy.shevchenko@linux.intel.com, Jiri Kosina <jikos@kernel.org>,
        linus.walleij@linaro.org, broonie@kernel.org,
        gregkh@linuxfoundation.org, hdegoede@redhat.com,
        james.clark@arm.com, james@equiv.tech, keescook@chromium.org,
        rafael@kernel.org, tglx@linutronix.de,
        Jeff LaBundy <jeff@labundy.com>, linux-input@vger.kernel.org,
        linux-i2c@vger.kernel.org
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Hi,

On Tue, Nov 28, 2023 at 12:45=E2=80=AFAM Chen-Yu Tsai <wenst@chromium.org> =
wrote:
>
> @@ -61,6 +61,17 @@ config CHROMEOS_TBMC
>           To compile this driver as a module, choose M here: the
>           module will be called chromeos_tbmc.
>
> +config CHROMEOS_OF_HW_PROBER
> +       bool "ChromeOS Device Tree Hardware Prober"

Any reason that it can't be a module?


> +       depends on OF
> +       depends on I2C
> +       select OF_DYNAMIC
> +       default OF

You probably don't want "default OF". This means that everyone will
automatically get this new driver enabled which is unlikely to be
right.


> +static int chromeos_of_hw_prober_probe(struct platform_device *pdev)
> +{
> +       for (size_t i =3D 0; i < ARRAY_SIZE(hw_prober_platforms); i++)
> +               if (of_machine_is_compatible(hw_prober_platforms[i].compa=
tible)) {
> +                       int ret;
> +
> +                       ret =3D hw_prober_platforms[i].prober(&pdev->dev,
> +                                                           hw_prober_pla=
tforms[i].data);
> +                       if (ret)

Should it only check for -EPROBE_DEFER here? ...and then maybe warn
for other cases and go through the loop? If there's some error
enabling the touchscreen I'd still want the trackpad to probe...


> +                               return ret;
> +               }
> +
> +       return 0;

Random thought: once we get here, the driver is useless / just wasting
memory. Any way to have it freed? ;-)