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References: <20211119015804.3824027-1-xji@analogixsemi.com>
In-Reply-To: <20211119015804.3824027-1-xji@analogixsemi.com>
From:   Robert Foss <robert.foss@linaro.org>
Date:   Tue, 4 Jan 2022 14:37:02 +0100
Message-ID: <CAG3jFytg88mWgA24ce4CbPKDA7HDdXOjC=AVxYrhv1c0Z5GTPA@mail.gmail.com>
Subject: Re: [PATCH v2] drm/bridge: anx7625: Check GPIO description to avoid crash
To:     Xin Ji <xji@analogixsemi.com>
Cc:     narmstrong@baylibre.com, dan.carpenter@oracle.com,
        laurent.pinchart@ideasonboard.com, jonas@kwiboo.se,
        jernej.skrabec@gmail.com, airlied@linux.ie, daniel@ffwll.ch,
        sam@ravnborg.org, pihsun@chromium.org, tzungbi@google.com,
        maxime@cerno.tech, drinkcat@google.com, hsinyi@chromium.org,
        dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
        bliang@analogixsemi.com, qwen@analogixsemi.com
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

On Fri, 19 Nov 2021 at 02:58, Xin Ji <xji@analogixsemi.com> wrote:
>
> As GPIO probe function "devm_gpiod_get_optional()" may return error
> code, driver should identify GPIO desc as NULL to avoid crash.
>
> Acked-by: Tzung-Bi Shih <tzungbi@google.com>
> Signed-off-by: Xin Ji <xji@analogixsemi.com>
> ---
>  drivers/gpu/drm/bridge/analogix/anx7625.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
>
> diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.c b/drivers/gpu/drm/bridge/analogix/anx7625.c
> index 001fb39d9919..652ae814246d 100644
> --- a/drivers/gpu/drm/bridge/analogix/anx7625.c
> +++ b/drivers/gpu/drm/bridge/analogix/anx7625.c
> @@ -1098,9 +1098,18 @@ static void anx7625_init_gpio(struct anx7625_data *platform)
>         /* Gpio for chip power enable */
>         platform->pdata.gpio_p_on =
>                 devm_gpiod_get_optional(dev, "enable", GPIOD_OUT_LOW);
> +       if (IS_ERR_OR_NULL(platform->pdata.gpio_p_on)) {
> +               DRM_DEV_DEBUG_DRIVER(dev, "no enable gpio found\n");
> +               platform->pdata.gpio_p_on = NULL;
> +       }
> +
>         /* Gpio for chip reset */
>         platform->pdata.gpio_reset =
>                 devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
> +       if (IS_ERR_OR_NULL(platform->pdata.gpio_reset)) {
> +               DRM_DEV_DEBUG_DRIVER(dev, "no reset gpio found\n");
> +               platform->pdata.gpio_reset = NULL;
> +       }
>
>         if (platform->pdata.gpio_p_on && platform->pdata.gpio_reset) {
>                 platform->pdata.low_power_mode = 1;
> --
> 2.25.1
>

Reviewed-by: Robert Foss <robert.foss@linaro.org>