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References: <20211018220504.8301-1-shreeya.patel@collabora.com>
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From:   Linus Walleij <linus.walleij@linaro.org>
Date:   Sun, 24 Oct 2021 23:49:44 +0200
Message-ID: <CACRpkdZCMH5OBwfiPwMT1CifDV28H4aTxy_N_4dHs0Qg0ENOAw@mail.gmail.com>
Subject: Re: [PATCH v2] gpio: Return EPROBE_DEFER if gc->to_irq is NULL
To:     Shreeya Patel <shreeya.patel@collabora.com>
Cc:     Bartosz Golaszewski <bgolaszewski@baylibre.com>,
        Wolfram Sang <wsa@kernel.org>, krisman@collabora.com,
        Sebastian Reichel <sebastian.reichel@collabora.com>,
        Collabora Kernel ML <kernel@collabora.com>,
        "open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        linux-i2c <linux-i2c@vger.kernel.org>
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On Tue, Oct 19, 2021 at 12:05 AM Shreeya Patel
<shreeya.patel@collabora.com> wrote:

> We are racing the registering of .to_irq when probing the
> i2c driver. This results in random failure of touchscreen
> devices.
>
> Following errors could be seen in dmesg logs when gc->to_irq is NULL
>
> [2.101857] i2c_hid i2c-FTS3528:00: HID over i2c has not been provided an Int IRQ
> [2.101953] i2c_hid: probe of i2c-FTS3528:00 failed with error -22
>
> To avoid this situation, defer probing until to_irq is registered.
>
> This issue has been reported many times in past and people have been
> using workarounds like changing the pinctrl_amd to built-in instead
> of loading it as a module or by adding a softdep for pinctrl_amd into
> the config file.
>
> References :-
> https://bugzilla.kernel.org/show_bug.cgi?id=209413
> https://github.com/Syniurge/i2c-amd-mp2/issues/3
>
> Signed-off-by: Shreeya Patel <shreeya.patel@collabora.com>
>
> ---
> Changes in v2
>   - Add a condition to check for irq chip to avoid bogus error.

This v2 looks acceptable to me.
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>

Yours,
Linus Walleij